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附件1生物等效性研究的统计学指导原则一、概述生物等效性（Bioequivalence, BE）研究是比较受试制剂（T）与参比制剂（R）的吸收速度和吸收程度差异是否在可接受范围内的研究，可用于化学药物仿制药的上市申请，也可用于已上市药物的变更（如新增规格、新增剂型、新的给药途径）申请。
目前生物等效性研究通常推荐使用平均生物等效性（Average Bioequivalence, ABE）方法。
平均生物等效性方法只比较药代动力学参数的平均水平，未考虑个体内变异及个体与制剂的交互作用引起的变异。
在某些情况下，可能需要考虑其他分析方法。
例如气雾剂的体外BE研究可采用群体生物等效性（Population Bioequivalence，PBE）方法，以评价制剂间药代动力学参数的平均水平及个体内变异是否等效。
本指导原则旨在为以药代动力学参数为终点评价指标的生物等效性研究的研究设计、数据分析和结果报告提供技术指导，是对生物等效性研究数据资料进行统计分析的一般原则。
在开展生物等效性研究时，除参考本指导原则的内容外，尚应综合参考《以药动学参数为终点评价指标的化学药物仿制药人体生物等效性研究技术指导原则》和《药物临床试验的生物统计学指导原则》等相关指导原则。
二、研究设计（一）总体设计考虑生物等效性研究可采用交叉设计或者平行组设计。
—1 —1.交叉设计生物等效性研究一般建议采用交叉设计的方法。
交叉设计的优势包括：可以有效减少个体间变异给试验评价带来的偏倚；在样本量相等的情况下，使用交叉设计比平行组设计具有更高的检验效能。
两制剂、两周期、两序列交叉设计是一种常见的交叉设计，见表1。
表1 两制剂、两周期、两序列交叉设计周期序列1 21 T R2 R T如果需要准确估计某一制剂的个体内变异，可采用重复交叉设计。
重复交叉设计包括部分重复（如两制剂、三周期、三序列）或者完全重复（如两制剂、四周期、两序列），见表2和表3。
表2 两制剂、三周期、三序列重复交叉设计周期序列1 2 31 T R R2 R T R3 R R T—2 —表3 两制剂、四周期、两序列重复交叉设计周期序列1 2 3 41 T R T R2 R T R T2.平行组设计在某些特定情况下（例如半衰期较长的药物），也可以使用平行组设计。
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指导原则编号: Array 1234567生物等效性研究的统计学指导原则89101112(征求意见稿)13141516171819二〇一八年六月20212223242526目录2728一、概述 (3)29二、研究设计 (3)3031（一）总体设计考虑 (3)32（二）样本量 (5)33（三）受试者脱落 (6)34（四）残留效应 (6)三、数据处理和分析 (6)3536（一）数据集 (6)37（二）数据转换 (7)38（三）统计假设与推断 (7)39（四）数据分析 (8)40（五）离群数据处理 (8)41（六）其他问题 (9)四、结果报告 (9)4243（一）随机化 (9)44（二）统计学方法 (9)（三）统计分析结果 (10)45五、数据管理 (10)46六、术语表 (10)4748495051一、概述52生物等效性（Bioequivalence, BE）研究是比较受试制剂（T）与53参比制剂（R）的吸收速度和吸收程度差异是否在可接受范围内的研54究，可用于化学药物仿制药的上市申请，也可用于已上市药物的变更55（如新增规格、新增剂型、新的给药途径）申请。
56目前生物等效性研究通常推荐使用平均生物等效性（Average 57Bioequivalence, ABE）方法。
平均生物等效性方法只比较药代动力学58参数的平均水平，未考虑个体内变异及个体与制剂的交互作用引起的59变异。
在某些情况下，可能需要考虑其他分析方法。
例如气雾剂的体60外BE研究可采用群体生物等效性（Population Bioequivalence，PBE）61方法，以评价制剂间药代动力学参数的平均水平及个体内变异是否等62效。
63本指导原则旨在为以药代动力学参数为终点评价指标的生物等64效性研究的研究设计、数据分析和结果报告提供技术指导，是对生物65等效性研究数据资料进行统计分析的一般原则。
在开展生物等效性研66究时，除参考本指导原则的内容外，尚应综合参考《以药动学参数为67终点评价指标的化学药物仿制药人体生物等效性研究技术指导原则》68和《药物临床试验的生物统计学指导原则》等相关指导原则。
以药动学参数为终点评价指标的化学药物仿制药人体生物等效性研究技术指导原则目录一、概述 (1)二、基本要求 (2)（一）研究总体设计 (2)（二）受试者选择 (3)（三）参比制剂的选择 (3)（四）给药方法 (3)（五）餐后生物等效性研究 (4)（六）生物样品分析 (4)（七）用于评价生物等效性的药动学参数 (5)（八）生物等效性试验实施过程及数据统计分析的具体要求 (6)三、常见剂型的生物等效性研究 (6)（一）口服溶液 (6)（二）常释制剂：胶囊和片剂 (6)（三）混悬液 (7)（四）调释制剂 (7)（五）咀嚼片 (8)四、特殊问题考虑要点 (8)（一）检测物质 (8)（二）长半衰期药物 (9)（三）Cmax出现在首个样品的情况 (10)（四）含酒精饮料对调释制剂的影响 (10)（五）内源性化合物 (10)（六）口服给药发挥局部作用的药物 (11)以药动学参数为终点评价指标的化学药物仿制药人体生物等效性研究技术指导原则一、概述本指导原则主要阐述以药动学参数为终点评价指标的化学药物仿制药人体生物等效性试验的一般原则，适用于机体内药物浓度能够准确测定并可用于生物等效性评价的口服及部分非口服给药制剂（如透皮吸收制剂、部分直肠给药和鼻腔给药的制剂等）。
进行生物等效性试验时，除本指导原则外，尚应综合参考生物样品定量分析方法验证指导原则等相关指导原则开展试验。
生物等效性（bioequivalence，BE）定义如下：在相似的试验条件下单次或多次服用相同剂量的试验药物后，受试制剂中药物的吸收速度和吸收程度与参比制剂的差异在可接受范围内。
按照研究方法评价效力的优先顺序，BE研究方法包括药代动力学研究、药效动力学研究、临床研究和体外研究。
药代动力学（药动学）研究：对于大多数药物而言，BE研究着重考察药物自制剂释放进入机体循环的过程，通常将受试制剂在机体内的暴露情况与参比制剂进行比较。
在上述定义的基础上，以药代动力学参数为终点评价指标的生物等效性研究又可表述为：通过测定可获得的生物基质（如血液、血浆、血清）中的活性物质，取得药代动力学参数作为终点指标，藉此反映药物释放并被吸收进入循环系统的速度和程度。
Technique Guideline for Human Bioavailability and BioequivalenceStudies on Chemical Drug ProductsContents(Ⅰ) Establishment and Validation for Biological Sample Analysis Methods (2)1. Common Analysis Methods (2)2. Method Validation (2)2.1 Specificity (2)2.2 Calibration Curve and Quantitative Scale (3)2.3 Lower Limit of Quantitation (LLOQ) (3)2.4 Precision and Accuracy (4)2.5 Sample Stability (4)2.6 Percent recovery of Extraction (4)2.7 Method Validation with microbiology and immunology (4)3. Methodology Quality Control (5)(Ⅱ) Design and Conduct of Studies (5)1. Cross-over Design (5)2. Selection of Subjects (6)2.1 Inclusion Criteria of Subjects: (6)2.2 Cases of Subjects (7)2.3 Division into Groups of the Subjects (7)3. Test and Reference Product, T and R (8)4. Sampling (8)(Ⅲ) Result Evaluation (9)(Ⅳ) Submission of the Contents of Clinical Study Reports (9)Technique Guideline for Human Bioavailability and BioequivalenceStudies on Chemical Drug ProductsSpecific Requirements for BA and BE Studies(Ⅰ) Establishment and Validation for Biological Sample Analysis MethodsBiological samples generally come from the whole blood, serum, plasma, urine or other tissues. These samples have the characteristics such as little quantity for sampling, low drug concentration, much interference from endogenous substances, and great discrepancies between individuals. Therefore, according to the structure, biological medium and prospective concentration scale of the analytes, it is necessary to establish the proper quantitative assay methods for biological samples and to validate such methods.1. Common Analysis MethodsCommonly used analysis methods at present are as follows: (1) Chromatography: Gas Chromatography(GS), High Performance Liquid Chromatography (HPLC), Chromatography－mass Spectrometry (LC-MS, LC-MS-MS, GC-MS, GC-MS-MS), and so on. All the methods above can be used in detecting most of drugs; (2) Immunology methods: radiate immune analysis, enzyme immune analysis, fluorescent immune analysis and so on, all these can detect protein and polypeptide; (3) Microbiological methods: used in detecting antibiotic drug.Feasible and sensitive methods should be selected for biologic sample analysis as far as possible.2. Method ValidationEstablishment of reliable and reproducible quantitative assay methods is one of the keys to bioequivalence study. In order to ensure the method reliable, it is necessary to validate the method entirely and the following aspects should be generally inspected:2.1 SpecificityIt is the ability that the analysis method has to detect the analytes exactly and exclusively, when interference ingredient exists in the sample. Evidences should be provided that the analytes are the primary forms or specific active metabolites of the test drugs. Endogenous instances, the relevant metabolites and degradation products in biologic samples should not interfere with the detection of samples. If there are several analytes, each should be ensured not to be interfered, and the optimal detecting conditions of the analysis method should be maintained. As for chromatography, at least 6 samples from different subjects, which include chromatogram of blank biological samples, chromatogram of blank biologic samples added control substance (concentration labeled) and chromatogram of biologic samples after the administration should beexamined to reflect the specificity of the analytical procedure. As for mass spectra (LC-MS andLC-MS-MS) based on soft ionization, the medium effect such as ion suppression should be considered during analytic process.2.2 Calibration Curve and Quantitative ScaleCalibration curve reflects the relationship between the analyte concentration and the equipment response value and it is usually evaluated by the regression equation obtained from regression analysis (such as the weighted least squares method). The linear equation and correlation coefficient of the calibration curve should be provided to illustrate the degree of their linear correlation. The concentration scale of calibration curves is the quantitative scale. The examined results of concentration in the quantitative scale should reach the required precision and accuracy in the experiment.Dispensing calibration samples should use the same biological medium as that for analyte, and the respective calibration curve should be prepared for different biological samples. The number of calibration concentration points for establishing calibration curve lies on the possible concentration scale of the analyte and on the properties of relationship of analyte/response value. At least 6 concentration points should be used to establish calibration curve, more concentration points are needed as for non-linear correlation. The quantitative scale should cover the whole concentration scale of biological samples and should not use extrapolation out of the quantitative scale to calculate concentrations of the analyte. Calibration curve establishment should be accompanied with blank biologic samples. But this point is only for evaluating interference and not used for calculating. When the warp* between the measured value and the labeled value of each concentration point on the calibration curve is within the acceptable scale, the curve is determined to be eligible. The acceptable scale is usually prescribed that the warp of minimum concentration point is within ±20% while others within ±15%. Only the eligible calibration curve can be carried out for the quantitative calculation of clinical samples. When linear scale is somewhat broad, the weighted method is recommended to calculate the calibration curve in order to obtain a more exact value for low concentration points. ( *: warp=[(measured value － labeled value)/labeled value]×100%)2.3 Lower Limit of Quantitation (LLOQ)Lower limit of quntitation is the lowest concentration point on the calibration curve, indicating the lowest drug concentration in the tested sample, which meets the requirements of accuracy and precision. LLOQ should be able to detect drug concentrations of samples in 3~5 eliminationhalf-life or detect the drug concentration which is 1/10~/20 of the C max. The accuracy of the detection should be within 80~120% of the real concentration and its RSD should be less than 20%. The conclusions should be validated by the results from at least 5 standard samples.2.4 Precision and AccuracyPrecision is, under the specific analysis conditions, the dispersive degree of a series of the detection data from the samples with the same concentration and in the same medium. Usually, the RSD from inter- or intra- batches of the quality control samples is applied to examine the precision of the method. Generally speaking, the RSD should be less than 15% and that around LLOQ should be less than 20%. Accuracy is the contiguous degree between the tested and the real concentrations of the biological samples (namely, the warp between the tested and the real concentrations of the quality-controlled samples). The accuracy can be obtained by repeatedly detecting the analysis samples of known concentration which should be within 85~115% and which around LLOQ should be within 80~120%.Generally, 3 quality-control samples with high, middle and low concentrations are selected for validating the precision and accuracy of the method. The low concentration is chosen within three times of LLOQ, the high one is close to the upper limit of the calibration curve, and the middle concentration is within the low and the high ones. When the precision of the intra-batches is detected, each concentration should be prepared and detected at least 5 samples. In order to obtain the precision of inter-batches, at least 3 qualified analytical batches, 45 samples should be consecutively prepared and detected in different days.2.5 Sample StabilityAccording to specific instances, as for biological samples containing drugs, their stabilities should be examined under different conditions such as the room temperature, freezing, thaw and at different preservation time, in order to ensure the suitable store conditions and preservation times. Another thing that should be paid attention to is that the stabilities of the stock solution and the analyte in the solution after being treated with, should also be examined to ensure the accuracy and reproducibility of the test results.2.6 Percent recovery of ExtractionThe recovery of extraction is the ratio between the responsive value of the analytes recovered from the biological samples and that of the standard, which has the same meaning as the ratio of the analytes extracted from the biologic samples to be analyzed. The recovery of extraction of the 3 concentrations at high, middle and low should be examined and their results should be precise and reproduceable.2.7 Method Validation with microbiology and immunologyThe analysis method validation above mainly aims at chromatography, with many parameters and principles also applicable for microbiological and immunological analysis. However, some special aspects should be considered in the method validation. The calibration curve of the microbiological and immunological analysis is non-linear essentially, so more concentration pointsshould be used to construct the calibration curve than the chemical analysis. The accuracy of the results is the key factor and if repetitive detection can improve the accuracy, the same procedures should be taken in the method validation and the unknown sample detection.3. Methodology Quality ControlThe unknown samples are detected only after the method validation for analysis of biological samples has been completed. The quality control should be carried out during the concentration detection of the biological samples in order to ensure the reliability of the method in the practical application. It is recommended to assess the method by preparing quality-control samples of different concentrations by isolated individuals.Each unknown sample is usually detected for only one time and redetected if necessary. In the bioequivalence experiments, biological samples from the same individual had better to be detected in the same batch. The new calibration curve should be established when detecting biological samples of each analysis batch and high, middle and low concentrations of the quality-control samples should be detected at the same time. Each concentration should at least have two samples and should be equally distributed in the detection sequence of the unknown samples. When there are a large number of unknown samples in one analysis batch, the number of the quality-control samples at different concentrations should be increased to make the quality-control samples exceed 5% of the unknown sample population. The warp of detection result from the quality-control samples should usually be less than 15%, while the warp of the low concentration point should be less than 20% and at most 1/3 results of the quality-control samples at different concentrations are allowed to exceed the limit. If the detection results of the quality-control samples do not accord with the above requirements, the detection results of the samples in this analysis batch should be blanked out.The samples with concentrations higher than the upper quantitation limit should be detected once more using corresponding diluted blank medium. As for those samples with concentrations lower than the lower quantitation limit, during pharmacokinetics analysis, those sampled before reaching C max should be calculated as zero while those after C max should be calculated as ND (Not detectable), so as to decrease the effect of the zero value on the AUG calculation.(Ⅱ) Design and Conduct of Studies1. Cross-over DesignCurrently, the crossover design is the most wildly applied method in the BE study. As for the drug absorption and clearance, there is a transparent variation among individuals. Therefore, the coefficient of variability among individuals is far greater than that of the individual himself. That is why the bioequivalence study is generally required to be designed on the principle of self crossover control. Subjects are randomly divided into several groups and treated in sequence, of whichsubjects in one group take the test products first and then the reference product, while subjects in the other take the reference products first and then the test products. A long enough interval is essential between the two sequences, which is called Wash-out period. In this way, every subject has been treated twice or more times sequentially, which is equal to self-control. Therefore, the influence of drug products on drug absorption can be discriminated from the others, and the effect of various test periods and individual difference on the results can be eliminated.Two-sequence crossover design, three-sequence crossover design are adopted respectively according to the amount of the test product. If two varieties of drug products are to be compared, the two-treatment, two-period or two-sequence crossover design will be a preferable choice. When three varieties of products (two test products and one reference product) are included, thethree-formulation, three-period and double 3×3 Latin square design will be the suitable choice. And a long enough wash-out period is required among respective periods.Wash-out period is set on purpose to eliminate the mutual disturbance of the two varieties of drug products and avoid the treatment in the prior period from affecting that of the next period. And the wash-out period is generally longer than or equal to 7 elimination half lives.While the half-lives of some drugs or their active metabolites are too long, it is not suitable to apply the crossover design. Under this circumstance, parallel design is adopted, but the sample size should be enlarged.However, as for some highly variable drugs, except for increase of the subjects, repetitive cross-over design can be applied, to test possibly existing difference in individual when receive the same preparation twice.2. Selection of Subjects2.1 Inclusion Criteria of Subjects:The difference among individuals of the subjects should be minimized so that the difference of the drug products can be detected. The inclusion criteria and exclusion criteria should be noted in the trial scheme.Male healthy subjects are recruited generally. And as to the drugs of special purpose, proper subjects are recruited according to specific conditions. If female healthy subjects are recruited, the possibility of gestation should be avoided. If the drugs to be tested have some known adverse effects, which may do harm to the subjects, patients can also be included as the subjects.Age: 18~ 40 years old generally. The difference in age of the subjects in one batch should not be more than 10 years.Body weight: not less than 50kg as to normal subjects. Body Mass Index (BMI), which is equal to body weight (kg)/ body height 2 (m2), is generally required to be in the range of standard body weight. For the subjects in one batch, the taken dosage is the same, the range of the bodyweight, therefore, should not have great disparity.The subjects should receive the overall physical examination and be proved healthy. There is not medical history of heart, kidney, digestive tract, nervous system, mental anomaly, metabolism dysfunction, and so on. The physical examination has revealed normal blood pressure, heart rate, electrocardiogram, and respiratory rate. Laboratory data have revealed normal hepatic function, renal function and blood function. Those examinations are essential to prevent the metabolism of drugs in vivo from being interfered by the diseases. According to the classification and safety of drugs, special items examinations are required before, during and after the test, such as the blood glucose examination, which is required in the drug trial of hypoglyceimic agents.In order to avoid the interference by other drugs, no administration of other drugs is allowed from two weeks before and till the end of the test. Moreover, the cigarette, wine,beverage with caffeine, or some fruit juice that may affect the metabolism of the drug, is forbidden during the trial period also. The subjects had better have no appetite of cigarette and wine. Possible effects of the cigarette-addicted history should not be neglected in the discussion of results.Due to the metabolism variance resulted by known genetic polymorphism of drugs, the safety factor which may be effected by the slow metabolism speed of drugs should be considered.2.2 Cases of SubjectsThe cases of the subjects should meet the statistic requirement. And according to the current statistical methods, 18~24 cases are enough for most drugs to meet the requirement of sample size. But as to some drugs of high variability, more cases may be required correspondingly.The cases of a clinic trial are determined by three fundamental factors: （1）Significance level: namely, the value of α, for which value 0.05 or 5% is often adopted;（2）Power of a test: namely, the value of 1-β. β is the index that represents the probability of the type error, which is also theⅡprobability of misjudging the actually efficacy drugs as inefficient drugs, and value not less than 80% is commonly stated; （3）Coefficient of variance（CV%）and Difference（θ）: In the equivalence test of two drugs, the greater CV% and θ of the test indexes are, the more cases are required. The CV% and θ are unknown before the trial and can only be estimated by the above parameters of the owned reference products or running the preliminary test. Moreover, when a BA test has been finished, the value of N can be calculated according to the parameters such as θ, CV% and 1-β and then compared with the cases adopted in the finished BA test to determine whether the cases are reasonable or not.2.3 Division into Groups of the SubjectsThe subjects should be randomly divided into different comparable groups. The cases of the two groups should guarantee the best comparability.3. Test and Reference Product, T and RThe quality of the reference products directly affect the results reliability of BE trial. Generally, the domestic innovator products of the same dosage form which has been approval to be on sale are commonly selected. If it failed in acquiring the innovator products, the key product on the market can also be chosen as the reference product and the related quality certifications (such as the test results of the assay and dissolution) and the reasons for option should be provided. When it comes to the drug study of specific purpose, other on-sale dosage forms which are of the same kind and similar with pharmaceutics properties are selected as the reference products and those reference products should be already on sale and qualified in quality. The difference in assay between the test product and reference product should not exceed 5%.The test product should be the scale-up product or manufacture scale product, which is consistent with the quality standards for clinical application. And the indexes such as the in vitro dissolution, stability, content or valence assay, consistency reports between batches should be provided to the test unit for reference. As for some drugs, the data of polymorphs and optical isomers should be offered additionally. The test and reference product should be noted with the advanced development unit, batch number, specification, storage conditions and expiry date.For future reference, the test and reference product should be kept long enough after the trialtill the product is approved to be on sale.4. SamplingThere is a significant sense in designing the sampling point to guarantee both the reliability of the trial results and the rationality of calculating the pharmacokinetics parameters. Commonly, there should be preliminary tests or the pharmacokinetics literatures at home and abroad served as the evidences of designing the reasonable sampling points. When the blood-drug concentration assay is performed, the absorption phase, balance phase and clearance phase should be considered overall. There must be enough sampling points in every phase of the C-T curve and around the T max. The concentration curve, therefore, can fully reflect the entire procedure of the drugs distribution in vivo. And the blank blood samples are taken before the administration. Then at least 2~3 points are sampled in the absorption phase, at least 3points are sampled near the C max and 3-5 points in the clearance phase. Try to avoid that the first point gets the C max, and running the preliminary test may avoid this. When the continuously-sampling results show that the drugs’ primary forms or the active metabolites are at the point of 3～5 half- lives or the blood drug concentration is 1/10～1/20 ofC max, the values of AUC0-t/AUC0-∞are generally bigger than 80% .For the terminal clearance item doesn’t affect the evaluation of the products’ absorption process much, as to the long half-life drugs, the sampling periods should be continued long enough, so that the whole absorption process can be compared and analyzed. In the multiple administration study, the BA of some drugs is known to beaffected by the circadian rhythm, samples of which should be taken 24 hours continuously if possible.When the BA of the test drugs can’t be determined by detecting the blood-drug concentration, if the primary forms and the active metabolites of the test drugs are mainly be excreted in urine (more than 70% of the dosage), the BA assay may be performed by detecting the urine drug concentration, which is the test of the accumulated excretion quantity of drugs in urine to reflect the intake of drugs. The test products and trial scheme should accord with the demands of BA assay. The urine samples should be collected at intervals, and the collection frequency and intervals of which should meet the demands of evaluating the excretion degree of the primary forms and the active metabolites of the test products in urine. However this method cannot reflect the absorption speed of the drugs and gets many error factors, it is not recommended generally.Some drugs metabolize so rapidly in vivo that it is impossible to detect the primary forms in biological samples. Under these circumstances, the method determining the concentration of corresponding active metabolites in biological samples is adopted to perform the BA and BE studies.(Ⅲ) Result EvaluationAt present, the weighting function of AUC on drug absorption degree is comparatively affirmed, while C max and T max sometimes are not sensitive and seemly enough for weighting the absorption speed due to their dependence on the arrangement of sampling time, and they are therefore not suitable for drug products with multi-peak phenomena and for experiments with large individual variation. During the evaluation, if there are some special instances of inequivalence, a specific analysis should be performed for specific problems.As for AUC，the 90% confidence interval is generally required within the scope of 80%~125%. As for the drugs with narrow treatment spectrum, the above scope should likely be appropriately reduced. While in a few instances, having been validated to be reasonable, the scope can also be increased. So does C max. And as for T max, statistical evaluation is required only when its release speed is closely correlated to clinical therapeutic effects and safety, the equivalence scope of which can be ascertained according to the clinical requirements.When bioavailability ratio of test products is higher than that of reference products, which is called suprabioavailability, the following two instances can be considered: 1). Whether the reference product itself is a product with low bioavailability, which results in the improvement of the test drug's bioavailability; 2). The quality of the reference product meets the requirement, and the test drug really has higher bioavailability.(Ⅳ) Submission of the Contents of Clinical Study ReportsIn order to satisfy the demand of evaluation, a clinical report of bioequivalence study shouldinclude the following contents: (1)Experiment subjective;(2) Establishment of analysis methods for bioavailability samples and data of inspection, as well as provision of the essential chromatograms;(3) Detailed experiment design and operation methods , including data of all the subjects，sample cases，reference products，given dosage，usage and arrangement of sampling time;(4) All data about original measurement of unknown sample concentrations，pharmacokinetics parameters and drug-time curve of each subjects;(5) Data handling procedure and statistical analysis methods as well as detailed procedure and results of statistics;(6) Observation results of clinical adverse reactions after taking medicine，midway exit and out of record of subjects and the reasons;(7) Result analysis and necessary discussion on bioavailability or bioequivalence; (8) References. A brief abstract is required before the main body; at the end of the main body, names of the experiment unit, chief persons of the study and experiment personnel should be signed to take the responsibility for the results of the study.。
人体生物等效性试验豁免指导原则集团文件版本号：（M928-T898-M248-WU2669-I2896-DQ586-M1988）附件人体生物等效性试验豁免指导原则本指导原则适用于仿制药质量和疗效一致性评价中口服固体常释制剂申请生物等效性（Bioequivalence）豁免。
该指导原则是基于国际公认的生物药剂学分类系统（Biopharmaceutics Classification System，以下简称BCS）起草。
一、药物BCS分类BCS系统是按照药物的水溶性和肠道渗透性对其进行分类的一个科学架构。
当涉及到口服固体常释制剂中活性药物成分（Active Pharmaceutical Ingredient，以下简称API）在体内吸收速度和程度时，BCS系统主要考虑以下三个关键因素，即：药物溶解性（Solubility）、肠道渗透性（Intestinal permeability）和制剂溶出度（Dissolution）。
（一）溶解性溶解性分类根据申请生物等效豁免制剂的最高剂量而界定。
当单次给药的最高剂量对应的API在体积为250ml（或更少）、pH值在1.0—6.8范围内的水溶性介质中完全溶解，则可认为该药物为高溶解性。
250ml的量来源于标准的生物等效性研究中受试者用于服药的一杯水的量。
（二）渗透性渗透性分类与API在人体内的吸收程度间接相关（指吸收剂量的分数，而不是全身的生物利用度），与API在人体肠道膜间质量转移速率直接相关，或者也可以考虑其他可以用来预测药物在体内吸收程度的非人体系统（如使用原位动物、体外上皮细胞培养等方法）对渗透性进行分类。
当一个口服药物采用质量平衡测定的结果或是相对于静脉注射的参照剂量，显示在体内的吸收程度≥85%以上（并且有证据证明药物在胃肠道稳定性良好），则可说明该药物具有高渗透性。
（三）溶出度口服固体常释制剂具有快速溶出的定义是：采用中国药典2015版附录通则（0931）方法1 （篮法），转速为每分钟100转,或是方法2（桨法），转速为每分钟50或75转，溶出介质体积为500ml（或更少），在溶出介质：（1）0.1mol/L HCl或是不含酶的模拟胃液；（2）pH4.5缓冲介质；（3）pH6.8缓冲介质或是不含酶的模拟肠液中，30分钟内API的溶出均能达到标示量的85%以上。
附件2高变异药物生物等效性研究技术指导原则一、概述化学药物制剂生物等效性评价，通常采用平均生物等效性（Average bioequivalence, ABE）方法，等效标准为受试制剂与参比制剂的主要药动学参数（AUC和C max）几何均值比的90%置信区间落在80.00%~125.00%范围内。
某些药物由于生物利用度过低、酸不稳定、吸收前的广泛代谢等原因，导致一个或多个药动学参数的个体内变异系数（Within-subject coefficient of variation, CV W%）大于或等于30%，称为高变异药物（Highly variable drug, HVD）。
在其他因素不变的情况下，随着个体内变异增加，生物等效性研究所需受试者数量也会相应增加。
对于高变异药物，采用常规样本量和等效性判定标准，有时即使参比制剂与自身相比较，也可能出现不能证明其生物等效的情况。
对于安全性较好、治疗窗较宽的高变异药物，在充分科学论证的基础上和保证公众用药安全、有效的前提下，通过部分重复或完全重复交叉设计，根据参比制剂的个体内变异，采用参比制剂标度的平均生物等效性（Reference-scaled average bioequivalence, RSABE）方法，将等效性判定标准在80.00%~125.00%的基础上适当放宽，可减少不必要的人群暴露，达到科学评价不同制剂是否生物等效的目的。
当采用RSABE方法进行生物等效性评价时，应首先根据药—1 —物体内过程特点等因素，分析造成药物制剂高变异特征的可能原因，结合预试验或文献报道结果，充分论证和评估采用该方法进行生物等效性评价的适用性。
采用部分重复或完全重复交叉设计，在符合《药物临床试验质量管理规范》（GCP）相关要求的条件下，正式试验获得的参比制剂药动学参数个体内变异系数大于或等于30%时，方可适用RSABE方法进行生物等效性评价。
本指导原则旨在为开展以药动学参数为主要终点指标的高变异化学药物生物等效性研究时，如何进行研究设计、样本量估算、统计分析、结果报告等方面提供技术指导。
窄治疗指数药物生物等效性研究技术指导原则（征求意见稿）2020年7月目录一、概述 (3)二、研究总体设计 (4)三、统计分析方法 (2)四、结果报告 (7)五、其他考虑 (7)六、参考文献 (5)窄治疗指数药物生物等效性研究技术指导原则12一、概述3窄治疗指数（Narrow therapeutic index，NTI）药物或窄4治疗窗药物一般是指剂量或血药浓度的微小变化即可能导5致治疗失败和/或严重不良反应，进而危及生命，或者导致永6久或严重的残疾或功能丧失的药物。
窄治疗指数药物通常具7有以下特点：血药浓度低于有效浓度可能导致治疗失败；有8效剂量与中毒剂量（或有效浓度与中毒浓度）接近；需要基9于药动学或药效学指标进行治疗药物监测；具有较低或中等10程度的个体内变异；临床应用中，剂量调整幅度通常很小等。
11与一般化学药物相比，窄治疗指数药物进行生物等效性12评价时，应采用更严格的等效性判定标准，以控制有效性和13安全性方面的风险。
14本指导原则作为《以药动学参数为终点评价指标的化学15药物仿制药人体生物等效性研究技术指导原则》及《生物等16效性研究的统计学指导原则》等的补充，旨在为窄治疗指数17药物开展以药动学参数为主要终点指标的生物等效性研究18时，如何进行研究设计、统计分析、结果报告等提供技术指19导。
20本指导原则仅代表药品监管部门当前的观点和认识。
随21着科学研究的进展，本指导原则中的相关内容将不断完善与22更新。
应用本指导原则时，请同时参考药物临床试验质量管23理规范（GCP）、国际人用药品注册技术协调会（ICH）和其24他国内外已发布的相关指导原则。
25二、研究总体设计26窄治疗指数药物的生物等效性研究，建议采用完全重复27（两制剂、四周期、两序列）交叉设计，以获得参比制剂和28受试制剂的个体内变异。
常采用的完全重复交叉设计见表1。
29表1 两制剂、四周期、两序列重复交叉设计30序列周期12341T R T R2R T R T试验前需充分估计所需的样本量，以保证足够的检验效31能。
日本《仿制药生物等效性试验指导原则2024版》日本仿制药生物等效性试验指导原则（Guideline for Bioequivalence Studies of Generic Products in Japan 2024）是日本药物和医疗器械局（PMDA）于2024年发布的文件，用于指导仿制药生物等效性试验的设计和进行。
本文将对该指导原则进行详细介绍。
该指导原则的目的是为了确保仿制药的质量、安全性和疗效与原始药物相似。
通过进行生物等效性试验，可以评估仿制药与原始药物在体内的药物浓度之间的相似程度，以确定两者的等效性。
这样一来，患者在使用仿制药时就能够获得相同的疗效，并且不会出现因药物替代而引发的风险。
根据指导原则，生物等效性试验可以采用交叉设计或平行设计。
在交叉设计中，受试者在不同时段内分别接受原始药物和仿制药的治疗，以便比较两者的药物浓度曲线。
而在平行设计中，受试者被分为两组，一组接受原始药物治疗，另一组接受仿制药治疗，然后比较两组之间的药物浓度。
值得注意的是，这一指导原则要求生物等效性试验的设计需要满足一定的统计学要求。
试验需要进行样本量计算，以确保可以获得具有统计学意义的结果。
此外，试验还应能够检测到与药物浓度相关的不良事件和药物相互作用。
此外，指导原则还对生物等效性试验的实施提出了一些具体要求。
例如，试验中应选择适当的受试者人群，他们应具备与使用仿制药和原始药物的真实患者相似的特征。
试验期间需要监测受试者的生理参数、药物浓度以及可能的不良事件，以确保试验的安全性和可靠性。
最后，指导原则还针对生物等效性试验结果的数据分析和报告提出了一些要求。
试验人员需要对试验所得数据进行适当的统计分析，以确定两种药物是否具有生物等效性。
同时，指导原则还要求试验结果的报告应包括试验设计、方法、数据和结论等方面的详细信息。
总之，日本《仿制药生物等效性试验指导原则2024版》为仿制药生物等效性试验的设计和实施提供了明确的指导。
附件1生物等效性研究的统计学指导原则一、概述生物等效性（Bioequivalence, BE）研究是比较受试制剂（T）与参比制剂（R）的吸收速度和吸收程度差异是否在可接受范围内的研究，可用于化学药物仿制药的上市申请，也可用于已上市药物的变更（如新增规格、新增剂型、新的给药途径）申请。
目前生物等效性研究通常推荐使用平均生物等效性（Average Bioequivalence, ABE）方法。
平均生物等效性方法只比较药代动力学参数的平均水平，未考虑个体内变异及个体与制剂的交互作用引起的变异。
在某些情况下，可能需要考虑其他分析方法。
例如气雾剂的体外BE研究可采用群体生物等效性（Population Bioequivalence，PBE）方法，以评价制剂间药代动力学参数的平均水平及个体内变异是否等效。
本指导原则旨在为以药代动力学参数为终点评价指标的生物等效性研究的研究设计、数据分析和结果报告提供技术指导，是对生物等效性研究数据资料进行统计分析的一般原则。
在开展生物等效性研究时，除参考本指导原则的内容外，尚应综合参考《以药动学参数为终点评价指标的化学药物仿制药人体生物等效性研究技术指导原则》和《药物临床试验的生物统计学指导原则》等相关指导原则。
二、研究设计（一）总体设计考虑生物等效性研究可采用交叉设计或者平行组设计。
1.交叉设计生物等效性研究一般建议采用交叉设计的方法。
交叉设计的优势包括：可以有效减少个体间变异给试验评价带来的偏倚；在样本量相等的情况下，使用交叉设计比平行组设计具有更高的检验效能。
两制剂、两周期、两序列交叉设计是一种常见的交叉设计，见表1。
表1 两制剂、两周期、两序列交叉设计—1 —周期序列1 21 T R2 R T如果需要准确估计某一制剂的个体内变异，可采用重复交叉设计。
重复交叉设计包括部分重复（如两制剂、三周期、三序列）或者完全重复（如两制剂、四周期、两序列），见表2和表3。
表2 两制剂、三周期、三序列重复交叉设计周期序列1 2 31 T R R2 R T R3 R R T表3 两制剂、四周期、两序列重复交叉设计周期序列1 2 3 41 T R T R2 R T R T2.平行组设计在某些特定情况下（例如半衰期较长的药物），也可以使用平行组设计。
Technique Guideline for Human Bioavailability and BioequivalenceStudies on Chemical Drug ProductsContents(Ⅰ) Establishment and Validation for Biological Sample Analysis Methods (2)1. Common Analysis Methods (2)2. Method Validation (2)2.1 Specificity (2)2.2 Calibration Curve and Quantitative Scale (3)2.3 Lower Limit of Quantitation (LLOQ) (3)2.4 Precision and Accuracy (4)2.5 Sample Stability (4)2.6 Percent recovery of Extraction (4)2.7 Method Validation with microbiology and immunology (4)3. Methodology Quality Control (5)(Ⅱ) Design and Conduct of Studies (5)1. Cross-over Design (5)2. Selection of Subjects (6)2.1 Inclusion Criteria of Subjects: (6)2.2 Cases of Subjects (7)2.3 Division into Groups of the Subjects (7)3. Test and Reference Product, T and R (8)4. Sampling (8)(Ⅲ) Result Evaluation (9)(Ⅳ) Submission of the Contents of Clinical Study Reports (9)Technique Guideline for Human Bioavailability and BioequivalenceStudies on Chemical Drug ProductsSpecific Requirements for BA and BE Studies(Ⅰ) Establishment and Validation for Biological Sample Analysis MethodsBiological samples generally come from the whole blood, serum, plasma, urine or other tissues. These samples have the characteristics such as little quantity for sampling, low drug concentration, much interference from endogenous substances, and great discrepancies between individuals. Therefore, according to the structure, biological medium and prospective concentration scale of the analytes, it is necessary to establish the proper quantitative assay methods for biological samples and to validate such methods.1. Common Analysis MethodsCommonly used analysis methods at present are as follows: (1) Chromatography: Gas Chromatography(GS), High Performance Liquid Chromatography (HPLC), Chromatography－mass Spectrometry (LC-MS, LC-MS-MS, GC-MS, GC-MS-MS), and so on. All the methods above can be used in detecting most of drugs; (2) Immunology methods: radiate immune analysis, enzyme immune analysis, fluorescent immune analysis and so on, all these can detect protein and polypeptide; (3) Microbiological methods: used in detecting antibiotic drug.Feasible and sensitive methods should be selected for biologic sample analysis as far as possible.2. Method ValidationEstablishment of reliable and reproducible quantitative assay methods is one of the keys to bioequivalence study. In order to ensure the method reliable, it is necessary to validate the method entirely and the following aspects should be generally inspected:2.1 SpecificityIt is the ability that the analysis method has to detect the analytes exactly and exclusively, when interference ingredient exists in the sample. Evidences should be provided that the analytes are the primary forms or specific active metabolites of the test drugs. Endogenous instances, the relevant metabolites and degradation products in biologic samples should not interfere with the detection of samples. If there are several analytes, each should be ensured not to be interfered, and the optimal detecting conditions of the analysis method should be maintained. As for chromatography, at least 6 samples from different subjects, which include chromatogram of blank biological samples, chromatogram of blank biologic samples added control substance (concentration labeled) and chromatogram of biologic samples after the administration should beexamined to reflect the specificity of the analytical procedure. As for mass spectra (LC-MS andLC-MS-MS) based on soft ionization, the medium effect such as ion suppression should be considered during analytic process.2.2 Calibration Curve and Quantitative ScaleCalibration curve reflects the relationship between the analyte concentration and the equipment response value and it is usually evaluated by the regression equation obtained from regression analysis (such as the weighted least squares method). The linear equation and correlation coefficient of the calibration curve should be provided to illustrate the degree of their linear correlation. The concentration scale of calibration curves is the quantitative scale. The examined results of concentration in the quantitative scale should reach the required precision and accuracy in the experiment.Dispensing calibration samples should use the same biological medium as that for analyte, and the respective calibration curve should be prepared for different biological samples. The number of calibration concentration points for establishing calibration curve lies on the possible concentration scale of the analyte and on the properties of relationship of analyte/response value. At least 6 concentration points should be used to establish calibration curve, more concentration points are needed as for non-linear correlation. The quantitative scale should cover the whole concentration scale of biological samples and should not use extrapolation out of the quantitative scale to calculate concentrations of the analyte. Calibration curve establishment should be accompanied with blank biologic samples. But this point is only for evaluating interference and not used for calculating. When the warp* between the measured value and the labeled value of each concentration point on the calibration curve is within the acceptable scale, the curve is determined to be eligible. The acceptable scale is usually prescribed that the warp of minimum concentration point is within ±20% while others within ±15%. Only the eligible calibration curve can be carried out for the quantitative calculation of clinical samples. When linear scale is somewhat broad, the weighted method is recommended to calculate the calibration curve in order to obtain a more exact value for low concentration points. ( *: warp=[(measured value － labeled value)/labeled value]×100%)2.3 Lower Limit of Quantitation (LLOQ)Lower limit of quntitation is the lowest concentration point on the calibration curve, indicating the lowest drug concentration in the tested sample, which meets the requirements of accuracy and precision. LLOQ should be able to detect drug concentrations of samples in 3~5 eliminationhalf-life or detect the drug concentration which is 1/10~/20 of the C max. The accuracy of the detection should be within 80~120% of the real concentration and its RSD should be less than 20%. The conclusions should be validated by the results from at least 5 standard samples.2.4 Precision and AccuracyPrecision is, under the specific analysis conditions, the dispersive degree of a series of the detection data from the samples with the same concentration and in the same medium. Usually, the RSD from inter- or intra- batches of the quality control samples is applied to examine the precision of the method. Generally speaking, the RSD should be less than 15% and that around LLOQ should be less than 20%. Accuracy is the contiguous degree between the tested and the real concentrations of the biological samples (namely, the warp between the tested and the real concentrations of the quality-controlled samples). The accuracy can be obtained by repeatedly detecting the analysis samples of known concentration which should be within 85~115% and which around LLOQ should be within 80~120%.Generally, 3 quality-control samples with high, middle and low concentrations are selected for validating the precision and accuracy of the method. The low concentration is chosen within three times of LLOQ, the high one is close to the upper limit of the calibration curve, and the middle concentration is within the low and the high ones. When the precision of the intra-batches is detected, each concentration should be prepared and detected at least 5 samples. In order to obtain the precision of inter-batches, at least 3 qualified analytical batches, 45 samples should be consecutively prepared and detected in different days.2.5 Sample StabilityAccording to specific instances, as for biological samples containing drugs, their stabilities should be examined under different conditions such as the room temperature, freezing, thaw and at different preservation time, in order to ensure the suitable store conditions and preservation times. Another thing that should be paid attention to is that the stabilities of the stock solution and the analyte in the solution after being treated with, should also be examined to ensure the accuracy and reproducibility of the test results.2.6 Percent recovery of ExtractionThe recovery of extraction is the ratio between the responsive value of the analytes recovered from the biological samples and that of the standard, which has the same meaning as the ratio of the analytes extracted from the biologic samples to be analyzed. The recovery of extraction of the 3 concentrations at high, middle and low should be examined and their results should be precise and reproduceable.2.7 Method Validation with microbiology and immunologyThe analysis method validation above mainly aims at chromatography, with many parameters and principles also applicable for microbiological and immunological analysis. However, some special aspects should be considered in the method validation. The calibration curve of the microbiological and immunological analysis is non-linear essentially, so more concentration pointsshould be used to construct the calibration curve than the chemical analysis. The accuracy of the results is the key factor and if repetitive detection can improve the accuracy, the same procedures should be taken in the method validation and the unknown sample detection.3. Methodology Quality ControlThe unknown samples are detected only after the method validation for analysis of biological samples has been completed. The quality control should be carried out during the concentration detection of the biological samples in order to ensure the reliability of the method in the practical application. It is recommended to assess the method by preparing quality-control samples of different concentrations by isolated individuals.Each unknown sample is usually detected for only one time and redetected if necessary. In the bioequivalence experiments, biological samples from the same individual had better to be detected in the same batch. The new calibration curve should be established when detecting biological samples of each analysis batch and high, middle and low concentrations of the quality-control samples should be detected at the same time. Each concentration should at least have two samples and should be equally distributed in the detection sequence of the unknown samples. When there are a large number of unknown samples in one analysis batch, the number of the quality-control samples at different concentrations should be increased to make the quality-control samples exceed 5% of the unknown sample population. The warp of detection result from the quality-control samples should usually be less than 15%, while the warp of the low concentration point should be less than 20% and at most 1/3 results of the quality-control samples at different concentrations are allowed to exceed the limit. If the detection results of the quality-control samples do not accord with the above requirements, the detection results of the samples in this analysis batch should be blanked out.The samples with concentrations higher than the upper quantitation limit should be detected once more using corresponding diluted blank medium. As for those samples with concentrations lower than the lower quantitation limit, during pharmacokinetics analysis, those sampled before reaching C max should be calculated as zero while those after C max should be calculated as ND (Not detectable), so as to decrease the effect of the zero value on the AUG calculation.(Ⅱ) Design and Conduct of Studies1. Cross-over DesignCurrently, the crossover design is the most wildly applied method in the BE study. As for the drug absorption and clearance, there is a transparent variation among individuals. Therefore, the coefficient of variability among individuals is far greater than that of the individual himself. That is why the bioequivalence study is generally required to be designed on the principle of self crossover control. Subjects are randomly divided into several groups and treated in sequence, of whichsubjects in one group take the test products first and then the reference product, while subjects in the other take the reference products first and then the test products. A long enough interval is essential between the two sequences, which is called Wash-out period. In this way, every subject has been treated twice or more times sequentially, which is equal to self-control. Therefore, the influence of drug products on drug absorption can be discriminated from the others, and the effect of various test periods and individual difference on the results can be eliminated.Two-sequence crossover design, three-sequence crossover design are adopted respectively according to the amount of the test product. If two varieties of drug products are to be compared, the two-treatment, two-period or two-sequence crossover design will be a preferable choice. When three varieties of products (two test products and one reference product) are included, thethree-formulation, three-period and double 3×3 Latin square design will be the suitable choice. And a long enough wash-out period is required among respective periods.Wash-out period is set on purpose to eliminate the mutual disturbance of the two varieties of drug products and avoid the treatment in the prior period from affecting that of the next period. And the wash-out period is generally longer than or equal to 7 elimination half lives.While the half-lives of some drugs or their active metabolites are too long, it is not suitable to apply the crossover design. Under this circumstance, parallel design is adopted, but the sample size should be enlarged.However, as for some highly variable drugs, except for increase of the subjects, repetitive cross-over design can be applied, to test possibly existing difference in individual when receive the same preparation twice.2. Selection of Subjects2.1 Inclusion Criteria of Subjects:The difference among individuals of the subjects should be minimized so that the difference of the drug products can be detected. The inclusion criteria and exclusion criteria should be noted in the trial scheme.Male healthy subjects are recruited generally. And as to the drugs of special purpose, proper subjects are recruited according to specific conditions. If female healthy subjects are recruited, the possibility of gestation should be avoided. If the drugs to be tested have some known adverse effects, which may do harm to the subjects, patients can also be included as the subjects.Age: 18~ 40 years old generally. The difference in age of the subjects in one batch should not be more than 10 years.Body weight: not less than 50kg as to normal subjects. Body Mass Index (BMI), which is equal to body weight (kg)/ body height 2 (m2), is generally required to be in the range of standard body weight. For the subjects in one batch, the taken dosage is the same, the range of the bodyweight, therefore, should not have great disparity.The subjects should receive the overall physical examination and be proved healthy. There is not medical history of heart, kidney, digestive tract, nervous system, mental anomaly, metabolism dysfunction, and so on. The physical examination has revealed normal blood pressure, heart rate, electrocardiogram, and respiratory rate. Laboratory data have revealed normal hepatic function, renal function and blood function. Those examinations are essential to prevent the metabolism of drugs in vivo from being interfered by the diseases. According to the classification and safety of drugs, special items examinations are required before, during and after the test, such as the blood glucose examination, which is required in the drug trial of hypoglyceimic agents.In order to avoid the interference by other drugs, no administration of other drugs is allowed from two weeks before and till the end of the test. Moreover, the cigarette, wine,beverage with caffeine, or some fruit juice that may affect the metabolism of the drug, is forbidden during the trial period also. The subjects had better have no appetite of cigarette and wine. Possible effects of the cigarette-addicted history should not be neglected in the discussion of results.Due to the metabolism variance resulted by known genetic polymorphism of drugs, the safety factor which may be effected by the slow metabolism speed of drugs should be considered.2.2 Cases of SubjectsThe cases of the subjects should meet the statistic requirement. And according to the current statistical methods, 18~24 cases are enough for most drugs to meet the requirement of sample size. But as to some drugs of high variability, more cases may be required correspondingly.The cases of a clinic trial are determined by three fundamental factors: （1）Significance level: namely, the value of α, for which value 0.05 or 5% is often adopted;（2）Power of a test: namely, the value of 1-β. β is the index that represents the probability of the type error, which is also theⅡprobability of misjudging the actually efficacy drugs as inefficient drugs, and value not less than 80% is commonly stated; （3）Coefficient of variance（CV%）and Difference（θ）: In the equivalence test of two drugs, the greater CV% and θ of the test indexes are, the more cases are required. The CV% and θ are unknown before the trial and can only be estimated by the above parameters of the owned reference products or running the preliminary test. Moreover, when a BA test has been finished, the value of N can be calculated according to the parameters such as θ, CV% and 1-β and then compared with the cases adopted in the finished BA test to determine whether the cases are reasonable or not.2.3 Division into Groups of the SubjectsThe subjects should be randomly divided into different comparable groups. The cases of the two groups should guarantee the best comparability.3. Test and Reference Product, T and RThe quality of the reference products directly affect the results reliability of BE trial. Generally, the domestic innovator products of the same dosage form which has been approval to be on sale are commonly selected. If it failed in acquiring the innovator products, the key product on the market can also be chosen as the reference product and the related quality certifications (such as the test results of the assay and dissolution) and the reasons for option should be provided. When it comes to the drug study of specific purpose, other on-sale dosage forms which are of the same kind and similar with pharmaceutics properties are selected as the reference products and those reference products should be already on sale and qualified in quality. The difference in assay between the test product and reference product should not exceed 5%.The test product should be the scale-up product or manufacture scale product, which is consistent with the quality standards for clinical application. And the indexes such as the in vitro dissolution, stability, content or valence assay, consistency reports between batches should be provided to the test unit for reference. As for some drugs, the data of polymorphs and optical isomers should be offered additionally. The test and reference product should be noted with the advanced development unit, batch number, specification, storage conditions and expiry date.For future reference, the test and reference product should be kept long enough after the trialtill the product is approved to be on sale.4. SamplingThere is a significant sense in designing the sampling point to guarantee both the reliability of the trial results and the rationality of calculating the pharmacokinetics parameters. Commonly, there should be preliminary tests or the pharmacokinetics literatures at home and abroad served as the evidences of designing the reasonable sampling points. When the blood-drug concentration assay is performed, the absorption phase, balance phase and clearance phase should be considered overall. There must be enough sampling points in every phase of the C-T curve and around the T max. The concentration curve, therefore, can fully reflect the entire procedure of the drugs distribution in vivo. And the blank blood samples are taken before the administration. Then at least 2~3 points are sampled in the absorption phase, at least 3points are sampled near the C max and 3-5 points in the clearance phase. Try to avoid that the first point gets the C max, and running the preliminary test may avoid this. When the continuously-sampling results show that the drugs’ primary forms or the active metabolites are at the point of 3～5 half- lives or the blood drug concentration is 1/10～1/20 ofC max, the values of AUC0-t/AUC0-∞are generally bigger than 80% .For the terminal clearance item doesn’t affect the evaluation of the products’ absorption process much, as to the long half-life drugs, the sampling periods should be continued long enough, so that the whole absorption process can be compared and analyzed. In the multiple administration study, the BA of some drugs is known to beaffected by the circadian rhythm, samples of which should be taken 24 hours continuously if possible.When the BA of the test drugs can’t be determined by detecting the blood-drug concentration, if the primary forms and the active metabolites of the test drugs are mainly be excreted in urine (more than 70% of the dosage), the BA assay may be performed by detecting the urine drug concentration, which is the test of the accumulated excretion quantity of drugs in urine to reflect the intake of drugs. The test products and trial scheme should accord with the demands of BA assay. The urine samples should be collected at intervals, and the collection frequency and intervals of which should meet the demands of evaluating the excretion degree of the primary forms and the active metabolites of the test products in urine. However this method cannot reflect the absorption speed of the drugs and gets many error factors, it is not recommended generally.Some drugs metabolize so rapidly in vivo that it is impossible to detect the primary forms in biological samples. Under these circumstances, the method determining the concentration of corresponding active metabolites in biological samples is adopted to perform the BA and BE studies.(Ⅲ) Result EvaluationAt present, the weighting function of AUC on drug absorption degree is comparatively affirmed, while C max and T max sometimes are not sensitive and seemly enough for weighting the absorption speed due to their dependence on the arrangement of sampling time, and they are therefore not suitable for drug products with multi-peak phenomena and for experiments with large individual variation. During the evaluation, if there are some special instances of inequivalence, a specific analysis should be performed for specific problems.As for AUC，the 90% confidence interval is generally required within the scope of 80%~125%. As for the drugs with narrow treatment spectrum, the above scope should likely be appropriately reduced. While in a few instances, having been validated to be reasonable, the scope can also be increased. So does C max. And as for T max, statistical evaluation is required only when its release speed is closely correlated to clinical therapeutic effects and safety, the equivalence scope of which can be ascertained according to the clinical requirements.When bioavailability ratio of test products is higher than that of reference products, which is called suprabioavailability, the following two instances can be considered: 1). Whether the reference product itself is a product with low bioavailability, which results in the improvement of the test drug's bioavailability; 2). The quality of the reference product meets the requirement, and the test drug really has higher bioavailability.(Ⅳ) Submission of the Contents of Clinical Study ReportsIn order to satisfy the demand of evaluation, a clinical report of bioequivalence study shouldinclude the following contents: (1)Experiment subjective;(2) Establishment of analysis methods for bioavailability samples and data of inspection, as well as provision of the essential chromatograms;(3) Detailed experiment design and operation methods , including data of all the subjects，sample cases，reference products，given dosage，usage and arrangement of sampling time;(4) All data about original measurement of unknown sample concentrations，pharmacokinetics parameters and drug-time curve of each subjects;(5) Data handling procedure and statistical analysis methods as well as detailed procedure and results of statistics;(6) Observation results of clinical adverse reactions after taking medicine，midway exit and out of record of subjects and the reasons;(7) Result analysis and necessary discussion on bioavailability or bioequivalence; (8) References. A brief abstract is required before the main body; at the end of the main body, names of the experiment unit, chief persons of the study and experiment personnel should be signed to take the responsibility for the results of the study.。
