Reference-scaled Average Bioequivalence Research Articles

Pharmacokinetics and Bioequivalence of Two Powders of Azithromycin for Suspension: A Nonblinded, Single-Dose, Randomized, Three-Way Crossover Study in Fed and Fasting States Among Healthy Chinese Volunteers.

Azithromycin, a macrolide antibiotic, is commonly used to treat mild-to-moderate bacterial infections. This research aimed to evaluate the pharmacokinetics (PK) properties and bioequivalence (BE) of two azithromycin (EQ 100 mg base/packet) powders for suspension in Chinese healthy participants in fed and fasting conditions. A total of 90 Chinese healthy participants were enrolled in this nonblinded, single-dose, randomized, semireplicate, three-period, three-sequence, crossover study. Of them, 42 and 40 were categorized to the fed and fasting conditions, respectively. The washout period between doses was 21 days. Blood specimens were harvested prior to administering the drug and 194 h following administration. The plasma levels of azithromycin were analyzed using a validated liquid chromatography-tandem mass spectrometry (LC-MS/MS) approach. PK parameters were measured using noncompartmental analysis. This research compared BE between the reference and test products using the average bioequivalence (ABE) or reference-scaled average bioequivalence (RSABE) method, considering the within-subject variability (SWR) of the reference preparation. Adverse events (AEs) were monitored to examine safety and tolerability. The RSABE method (SWR ≥ 0.294) was used to determine the BE of maximal plasma concentration (Cmax) in both fed and fasting conditions. In the ABE approach, (SWR < 0.294) was adopted to assess the BE of the area under the plasma concentration-time curve from time zero to the last measurable time point (AUC0-t) and determine the area under the plasma concentration time curve from time zero to time infinity (AUC0-inf). In the fasting condition, the point estimate of the test/reference ratio for Cmax was 1.08, with a 95% upper confidence bound of - 0.05 < 0.00. The geometric mean ratio (GMRs) for AUC0-t and AUC0-inf was 115.21% [90% confidence interval (CI) 107.25-123.27%] and 113.07% (90% CI 105.14-121.61%), respectively. In the fed condition, the point estimate of the test/reference ratio for Cmax was 0.94, with a 95% upper confidence bound of - 0.10 < 0.00. The GMR for AUC0-t and AUC0-inf was 99.51% (90% CI of 91.03-108.78%) and 99.43% (90% CI 91.73-107.78%), respectively. These data all satisfied the BE criteria for drugs with high variability. All AEs were transient and mild, and no severe AEs were observed. Our study indicated that the test and reference products of azithromycin (EQ 100 mg base/packet) powder for suspension were bioequivalent and safe in healthy Chinese participants, irrespective of the feeding condition. CLINICAL TRIAL REGISTRATION (CHINADRUGTRIALS.ORG.CN): CTR20232646, registered on 25 August 2023.

Pharmacokinetics and Bioequivalence of Two Formulations of Azithromycin Tablets: A Randomized, Single-Dose, Three-Period, Crossover Study in Healthy Chinese Volunteers Under Fasting and Fed Conditions.

Azithromycin is the first azalide antibiotic that is related to the macrolide family of antibiotics. Bioequivalence studies in China are initiated by the National Medical Products Administration (NMPA), which supports a generic consistency evaluation program for ensuring that generic products manufactured in China meet the required standards and provide equivalent therapeutic effects to their reference products. This study aimed to assess the bioequivalence of two azithromycin tablets under both fasting and fed conditions in healthy Chinese volunteers. This was a single-center, open-label, single-dose, randomized, three-way crossover trial with two independent groups (fasting group and fed group). A total of 72 healthy Chinese subjects (36 subjects in the fasting state and 36 subjects in the fed state) were enrolled and randomized to treatment. Blood samples were collected from 0 to 120 h after a single oral dose of a 250-mg generic azithromycin tablet (test, T) or branded azithromycin tablet (reference, R). The plasma concentrations of azithromycin were determined by high-performance liquid chromatography-tandem mass spectrometry (HPLC‒MS/MS). A non-compartmental analysis method was used to estimate the pharmacokinetic parameters. Adverse events were documented. In a fasting state, the bioequivalence of maximum plasma concentration (Cmax) was evaluated using the reference-scaled average bioequivalence (RSABE) approach (within-subject standard deviation, SWR >0.294), and the bioequivalence of area under the concentration-time curve from time 0 to the time of the last measurable plasma concentration (AUC0-t) and area under the concentration-time curve from time 0 extrapolated to infinity (AUC0-∞) were evaluated by the average bioequivalence (ABE) method (SWR < 0.294). The geometric mean ratio (GMR) of T/R for Cmax was 106.49%, while the 95% upper confidence bound was < 0. The GMRs of AUC0-t and AUC0-∞ were 103.34% and 101.28%, and the 90% confidence intervals (CIs) of the test/reference were 95.90-111.35%/94.85-108.15%, respectively. In the fed state, the RSABE approach was applied to estimate the bioequivalence of Cmax (SWR >0.294), and the ABE approach was applied to estimate the bioequivalence of AUC0-t and AUC0-∞ (SWR < 0.294). The GMR for Cmax was 99.80%, while the 95% upper confidence bound value was < 0. The GMRs of AUC0-t and AUC0-∞ were 97.07% and 98.15%, and the 90% CIs of the T/R were 90.02-104.68% and 90.66-106.25%, respectively. All adverse events were mild and transient. The trial indicated that the test and the reference azithromycin tablets were bioequivalent and well tolerated in healthy Chinese volunteers under both fasting and fed conditions. Clinicaltrials, ChiCTR2300071630 (retrospectively registered in 19/05/2023).

Pharmacokinetic Comparison of a Fixed-Dose Combination of Candesartan Cilexetil/Amlodipine/Atorvastatin Versus Co-administration of Individual Formulations in Healthy Participants.

Fixed-dose combinations (FDCs) of angiotensinII receptor blockers, calcium channel blockers, and statins are conventional therapeutic interventions prescribed for cardiovascular diseases. This study aimed at drawing a comparison between the pharmacokinetics and safety of an FDC and the corresponding individual formulations in healthy subjects. A randomized, open-label, single-dose, three-sequence, three-period, partially repeated crossover study was conducted with a cohort of healthy volunteers. A 14-day washout period was maintained between each of the three periods. In this study, candesartan cilexetil, amlodipine, and atorvastatin was administered orally as FDCs of 16/10/40mg in study1 and 16/5/20mg in study2. The maximum plasma concentration (Cmax) and area under the plasma concentration-time curve from time zero to the time of the last quantifiable concentration (AUClast) of candesartan, amlodipine, and atorvastatin were estimated as the geometric mean ratios (GMRs) and 90% confidence intervals (CIs) of the FDC to individual formulations. If the within-subject coefficient of variation (CVwr) of Cmax was greater than 0.3, the bioequivalence (BE) range calculated using the reference-scaled average bioequivalence was used to assess whether the 90%CI was within the BE range. The GMRs (90%CIs) for the AUClast for candesartan and amlodipine were 0.9612 (0.9158-1.0089)/0.9965 (0.9550-1.0397) and 1.0033 (0.9800-1.0271)/1.0067 (0.9798-1.0344), and the GMRs (90%CIs) for Cmax were 0.9600 (0.8953-1.0294)/0.9851 (0.9368-1.0359) and 1.0198 (0.9950-1.0453)/1.0003 (0.9694-1.0321) in studies1 and 2, respectively. The extended BE ranges calculated from the CVwr of the Cmax of atorvastatin were 0.7814-1.2797 and 0.7415-1.3485, respectively. The GMRs (90%CIs) for the AUClast of atorvastatin were 1.0532 (1.0082-1.1003)/1.0252 (0.9841-1.0680), and the GMRs (90%CIs) for Cmax were 1.0630 (0.9418-1.1997)/0.9888 (0.8792-1.1120) in studies1 and 2, respectively. The Cmax and AUClast values of candesartan cilexetil/amlodipine/atorvastatin 16/10/40mg and 16/5/20mg, respectively, were within the BE ranges. There were no clinically significant differences in safety between the two formulations. ClinicalTrials.gov identifier, study1: NCT04478097; study2: NCT04627207.

A single-dose, randomized, open-label, four-period, crossover equivalence trial comparing the clinical similarity of the proposed biosimilar rupatadine fumarate to reference Wystamm® in healthy Chinese subjects.

The aim of this study was to evaluate the bioequivalence of two formulations of rupatadine (10-mg tablets) under fasting and fed conditions in healthy Chinese subjects. A total of 72 subjects were randomly assigned to the fasting cohort (n = 36) and fed cohort (n = 36). Each cohort includes four single-dose observation periods and 7-day washout intervals. Blood samples were collected at several timepoints for up to 72h post-dose. The plasma concentration of rupatadine and the major active metabolites (desloratadine and 3-hydroxydesloratadine) were analyzed by a validated HPLC-MS/MS method. The non-compartmental analysis method was employed to determine the pharmacokinetic parameters. Based on the within-subject standard deviation of the reference formulation, a reference-scaled average bioequivalence or average bioequivalence method was used to evaluate the bioequivalence of the two formulations. For the fasting status, the reference-scaled average bioequivalence method was used to evaluate the bioequivalence of the maximum observed rupatadine concentration (Cmax; subject standard deviation > 0.294), while the average bioequivalence method was used to evaluate the bioequivalence of the area under the rupatadine concentration-time curve from time 0 to the last detectable concentration (AUC0-t) and from time 0 to infinity (AUC0-∞). The geometric mean ratio (GMR) of the test/reference for Cmax was 95.91%, and the upper bound of the 95% confidence interval was 95.91%. For AUC0-t and AUC0-∞ comparisons, the GMR and 90% confidence interval (CI) were 98.76% (93.88%-103.90%) and 98.71% (93.93%-103.75%), respectively. For the fed status, the subject standard deviation values of Cmax, AUC0-t, and AUC0-∞ were all <0.294; therefore, the average bioequivalence method was used. The GMR and 90% CI for Cmax, AUC0-t, and AUC0-∞ were 101.19% (91.64%-111.74%), 98.80% (94.47%-103.33%), and 98.63% (94.42%-103.03%), respectively. The two-sided 90% CI of the GMR for primary pharmacokinetic endpoints of desloratadine and 3-hydroxydesloratadine was also within 80%-125% for each cohort. These results met the bioequivalence criteria for highly variable drugs. All adverse events (AEs) were mild and transient. The test drug rupatadine fumarate showed a similar safety profile to the reference drug Wystamm® (J. Uriach y Compañía, S.A., Spain), and its pharmacokinetic bioequivalence was confirmed in healthy Chinese subjects based on fasting and postprandial status. http://www.chinadrugtrials.org.cn/index.html, identifier CTR20213217.

Evaluation of Bioequivalence for Avapritinib Tablets in Chinese Participants Under Fasting Conditions Using a Reference-Scaled Average Bioequivalence Method.

This study aimed to assess the bioequivalence of 2 avapritinib tablets formulations. A randomized, open-label, single-center trial was conducted on fasting, healthy Chinese participants. The study utilized a partial replicated design with 3 sequences and 3 periods. Participants were assigned to 1 of 3 sequences, with each sequence receiving the reference formulation twice and the test formulation once. Plasma samples were collected and analyzed to determine pharmacokinetic parameters. The bioequivalence of the 2 avapritinib formulations was assessed using reference-scaled average bioequivalence for the maximum plasma concentration (Cmax) and the average bioequivalence analysis for the area under the concentration-time curve (AUC). Out of 39 participants, 38 completed the study. For Cmax, the 1-sided 95% upper confidence interval (CI) bound from the scaled approach was -0.035 (<0) and the point estimate value was 0.958, falling inside the acceptance range of 0.8-1.25. For both the AUC over all concentrations measured (AUC0-t) and the AUC from time 0 to infinity (AUC0-inf), the 90% CIs of geometric mean ratios (0.87-1.01) also met the bioequivalence criteria of 0.8-1.25. Consequently, the study demonstrated that the 2 avapritinib formulations were bioequivalent under fasting conditions.

Scaled average bioequivalence methods for highly variable drugs: Leveling-off soft limits and the EMA's 2010 guideline (some ways to improve its type I error control).

The regulatory EMA's reference scaled average bioequivalence (RSABE) approach for highly variable drugs suffers from some type I error control problems at the neighborhood of the 30% coefficient of variation (CV), where the bioequivalence (BE) limits change from constant to linearly scaled. This paper analyses BE inference methods based on the "Leveling-off" (LO) soft sigmoid expanding BE limits that were proposed as an appealing surrogate for the EMA's limits and compares both approaches, on the replicated and partially replicated crossover designs. The initially proposed version of the LO method also has type I error inflation problems, albeit attenuated. But given its more mathematically regular character, it is more suitable for analytical corrections. Here we introduce two improvements over LO, one based on the application of Howe's method and the other based on correcting the estimation error. They further reduce the type I error inflation, although it does not disappear completely. Finally, the effect of heteroscedasticity on the above results is studied. It leads to inflation or deflation of the type I error, depending on the design and the type of heteroscedasticity (variability of the test product greater than that of the reference product or the opposite). The replicated design is much more stable against these effects than the partially replicated design and maintains these improvements much better.

Pharmacokinetics and safety of highly variable valsartan in single-pill combination with amlodipine versus its generic formulation: a randomized, three-cycle, three-sequence, partially replicated crossover phase I bioequivalence clinical trial.

Valsartan/amlodipine (I) is a single-pill combination (SPC) of an angiotensin II receptor blocker (ARB) and a calcium channel blocker (CCB) for treating hypertension. A clinical trial was performed to demonstrate that the test and reference valsartan/amlodipine formulations were bioequivalent under fasting and postprandial conditions. Participants were randomly divided into three sequences at a ratio of 1:1:1 for three-cycle, reference formulation replicated, crossover administration. The average bioequivalence (ABE) and reference-scaled average bioequivalence (RSABE) methods were used to evaluate BE using the main pharmacokinetic (PK) parameters. Overall, 45 eligible participants were enrolled in the postprandial trial, which was consistent with the fasting trial. For valsartan, the RSABE method was used to evaluate the BE of Cmax, while the ABE method was applied to evaluate the BE of AUC0-t and AUC0-∞. Both point estimates and 95% upper confidence bound met the BE criteria. For amlodipine, the ABE method was performed, and the 90% confidence intervals of the geometric mean ratios (GMR) for Cmax and AUC0-72h were all within 80%-125%, with the BE criteria being met. Therefore, the two formulations are bioequivalent and have similar safety profiles in healthy Chinese subjects. Clinical trial registration: [http://www.chinadrugtrials.org.cn/index.html], identifier [CTR20210214].

A Fully Replicate, Cross-over, Bioequivalence Study to Compare Two Prolonged Release, Multi-matrix Tablet Formulations of Budesonide in Healthy Indian Adults

Introduction: Budesonide is a synthetic, non halogenated corticosteroid, structurally related to 16α-hydroxyprednisolone, which is approved as first-line therapy for various gastrointestinal disorders. Budesonide prolonged-release tablets incorporating multi-matrix technology {Cortiment® 9 mg: Reference product (R)} were approved in India for induction of remission in adult patients with mild-to-moderate active ulcerative colitis. Aim: To assess the bioavailability, safety and tolerability of a single dose of generic budesonide prolonged-release tablets 9 mg {CortirowaTM OD; Test product (T)} and demonstrate their bioequivalence to Reference product (R) in healthy Indian adults under fasting conditions. Materials and Methods: In this randomised, open-label, single-dose, balanced, 2-treatment, 2-sequence, 4-period, fully replicate, cross-over bioequivalence study conducted from 12 July 2021 to 08 August 2021 at Ecron Acunova Limited, Manipal, India, 56 participants were randomly allocated (1:1) to treatment sequences Test-Reference-Test-Reference (TRTR) or Reference-Test-Reference-Test (RTRT). After a 10-hour overnight fast, participants were administered a single oral dose of T or R along with 240 mL of water. After each dose, a total of 26 venous blood samples (each 4 mL) were collected from each participant, at hourly intervals until 20 hours, and at 24, 30, 36, 48, and 72 hours. Plasma budesonide concentrations were analysed using a validated Liquid ChromatographyTandem-Mass Spectrometry (LC-MS/MS) method. Based on the randomisation sequences, the treatment periods were defined as test product treatment Period-1 (T1), test product treatment Period-2 (T2), reference product treatment Period-1 (R1), and reference product treatment Period-2 (R2). The primary pharmacokinetic parameters were peak plasma concentration (Cmax) and area under the concentration-time curve from time zero to the last sample with quantifiable concentration (AUC0-t). Results: Test and reference products were comparable in terms of mean (standard deviation) Cmax {pg/mL: T1=2163.0 (1423.9) and T2=2456.25 (1346.035) vs R1=2301.59 (1582.995) and R2=2437.62 (1437.665)} and AUC0-t {hr.pg/mL: T1=27938.0 (16431.23) and T2=33629.58 (18407.253) vs R1=25882.41 (17250.267) and R2=33146.25 (19350.222)}. As the within-subject Standard Deviation (SD) of R (SWR) for Cmax and AUC0-t was ≥0.294, the reference-Scaled Average Bioequivalence (SABE) approach was used. The bioequivalence criteria prespecified using the Scaled Average Bioequivalence (SABE) approach were met as the 95% upper confidence bound for (μT-μR)2 - θs2 WR of Cmax (-0.255371831) and AUC0-t (-0.445865013) were both ≤0, and the point estimate (T/R) geometric mean ratio of Cmax (0.97) and AUC0-t (1.06) were both within 0.80 and 1.25. While 10 Adverse Events (AEs) were reported in the study, all were of mild intensity. Conclusion: CortirowaTM OD was bioequivalent to Cortiment® 9 mg in healthy Indian adults under fasting conditions. Both the products were found to be well tolerated.

Bioequivalence of two tablet formulations of cefpodoxime proxetil in beagle dogs.

The pharmacokinetic profiles and bioequivalence of two cefpodoxime proxetil tablets were investigated in Beagle dogs. A single-dose, four-way complete replication and crossover design was used in the present study. A total of 28 healthy Beagle dogs (half male and female) with an average body weight of 11.1 kg were randomly allocated to this study. A whole reference or test tablet containing the equivalent of 100 mg of cefpodoxime was administered orally to each dog. Serial plasma samples were collected, and cefpodoxime concentrations were determined by ultra-performance liquid chromatography-mass spectrometry (UPLC-MS/MS). Then a non-compartmental method was used to calculate the pharmacokinetic parameters of both tablet formulations. The average bioequivalence (ABE) or reference-scaled average bioequivalence (RSABE) methods were used to determine the 90% confidence interval (CI) of AUCINF_obs and Cmax. No significant differences were observed for both parameters between both tablets. The test formulation was bioequivalent to the reference one because the 90% CI ranges of Cmax and AUCINF_obs were all between 80 and 125%.

Critical Remarks on Reference-Scaled Average Bioequivalence

More than a decade ago the option to assess highly variable drugs / drug products by reference-scaled average bioequivalence was introduced in regulatory practice. Recommended approaches differ between jurisdictions and may lead to different conclusions even for the same data set. According to our knowledge, implemented methods have not been directly compared for their operating characteristics (Type I Error and power). We performed Monte Carlo simulations to assess the consumer risk and the clinically relevant difference for the recommended regulatory settings. In all methods for reference-scaled average bioequivalence the Type I Error can be inflated with a consequently compromised consumer risk. Furthermore, the clinically relevant difference could vary between studies performed with the same reference product. Only average bioequivalence with fixed - widened - limits would both maintain the consumer risk and offer an unambiguously defined clinically not relevant difference. As long as such an approach is not implemented in regulatory practice, we recommend adjusting the level of the test a.

Pharmacokinetic and Safety Comparison of Two Capecitabine Tablets in Patients with Colorectal or Breast Cancer Under Fed Conditions: A Multicenter, Randomized, Open-Label, Three-Period, and Reference-Replicated Crossover Study.

In this study, we assessed the pharmacokinetics (PK), bioequivalence, and safety of 150mg capecitabine compared to the branded reference formulation in colorectal or breast cancer patients receiving a high-fat diet. This was a multicenter, open, random, balanced, three-period, three-sequence and semi-repetitive cross study with 48 subjects. In each study period, the eligible subject received the test or reference formulation, followed by a 1-day washout period. Serial blood samples for pharmacokinetic assessment were collected at predose up to 8h postdose. The plasma concentrations of capecitabine were analyzed by LC/MS-MS. Pharmacokinetic parameters (non-compartmental model) were assessed with WinNonlin software. The pharmacokinetic parameters assessed were the area under the plasma concentration-time curve from time 0 to the time of last measurable concentration (AUC0-t), the AUC from time zero to infinity (AUC0-∞), the peak plasma concentration of the drug (Cmax), the time needed to reach maximum concentration (Tmax), the elimination half-life (t1/2), and the terminal elimination rate (λz). All were analyzed using an analysis of variance (ANOVA) model after logarithmic transformation of the data. To establish the bioequivalence (BE) for capecitabine, reference-scaled average bioequivalence (RSABE) acceptance criteria and average bioequivalence (ABE) acceptance criteria were used. Safety and tolerability were assessed during the entire study period. Reference scaled maximum plasma concentration (Cmax) was higher than 0.294, permitting use of RSABE. The within-subject SDs of the reference intervention (SWR) for AUC0-t and AUC0-∞ were < 0.294, meeting ABE criteria. The point estimate for the geometric least squares mean (GLSM) ratio for the point estimate of Cmax was 0.962, within the range of 0.80-1.25. The 90% upper confidence boundary for the test/reference of GLSM ratios was 97.84-105.40% for AUC0-t and 97.33-103.51% for AUC0-∞, all of which were within the prespecified limits. The 90% confidence intervals for AUC0-t and AUC0-∞ and 95% upper confidence limit for Cmax indicated bioequivalence. No serious adverse events were found among the subjects. According to the criteria for bioequivalence, the test formulation was bioequivalent to the reference formulation in terms of the rate and extent of absorption under fed conditions by measurement of total capecitabine and was safe and well tolerated. NCT04420871.

Bioequivalence and Pharmacokinetic Profiles of Generic and Branded Obeticholic Acid in Healthy Chinese Subjects Under Fasting and Fed Conditions.

ObjectivesThis study was conducted to evaluate the bioequivalence (BE) of a generic form of obeticholic acid (OCA) and OcalivaTM under fasting and fed conditions and to determine the effects of food on the pharmacokinetic (PK) profiles of OCA in healthy Chinese subjects.MethodsA randomized, single-dose, three-sequence, three-period, partial replicated crossover study was conducted with a 21-day washout interval between periods under fasting (n=48) and fed (n=48) conditions. Blood samples for OCA and its metabolites Glyco-OCA and Tauro-OCA were collected up to 168 hours after administration in each period. PK parameters were calculated using the non-compartmental method. Geometric mean ratios for PK parameters of the test to reference drug under fasting and fed conditions and their 90% confidence intervals were estimated. Safety evaluations were carried out all through the study.ResultsA total of 91 subjects completed the study with 45 in a fasted state and 46 receiving a high-fat diet. There were no serious or unexpected drug-related adverse events occurring during the study. There was no significant difference in the main PK parameters of the two preparations, irrespective of the fasting or fed conditions. Under fasting and fed conditions, the SWR of lnCmax, lnAUC0-t and lnAUC0-∞ were 0.445, 0.370, 0.448, 0.340, 0.168, and 0.180, respectively. Thus, the average BE or the reference-scaled average BE was used to verify that the two preparations were bioequivalent under fasting and fed conditions. Compared with the fasting state, the AUC0-t of the test drug, the AUC0-t, and AUC0-∞ of the reference drug were higher in the fed state.ConclusionThe test drug and the reference drug were BE and well tolerated in Chinese healthy subjects under both fasting and fed conditions. Food-intake may cause a significant difference in the main PK parameters of the two preparations.

Pharmacokinetics and Bioequivalence of Two Formulations of Valsartan 80 mg Capsules: A Randomized, Single Dose, 4-Period Crossover Study in Healthy Chinese Volunteers Under Fasting and Fed Conditions.

PurposeTo compare the bioequivalence of two formulations of valsartan (80 mg capsules) under fasting and fed conditions in healthy Chinese volunteers using a full-replicate study design.MethodsA total of 78 Subjects were randomly assigned to fasting cohort (n = 48) or fed cohort (n = 30). Each cohort includes 4 single-dose observation periods and 3-day washout periods. Blood samples were collected at designed time point. Plasma concentration of valsartan was analyzed by a validated LC-MS/MS method. Noncompartmental analysis method was employed to determine the pharmacokinetic parameters. Based on the within-subject standard deviation (SWR) of the reference formulation, either reference-scaled average bioequivalence (RSABE) or average bioequivalence (ABE) method was used to evaluate the bioequivalence of the two formulations.ResultsUnder fasting conditions, the RSABE method was used to evaluate the bioequivalence of Cmax (SWR>0.294), while ABE method was used to evaluate the bioequivalence of AUC0-t and AUC0-∞. The geometric mean ratio (GMR) of the test/reference for Cmax was 99.52%, and the 95% upper confidence bound was <0. For AUC0-t and AUC0-∞ comparisons, GMRs were 102.07% and 101.92%, and the 90% CIs of the test/reference were 96.28%–108.21%, 96.28%–107.88%, respectively. Under fed conditions, the SWR value of Cmax, AUC0-t and AUC0-∞ all exceeded the cutoff value of 0.294 and therefore, the RSABE method was used. The GMRs for Cmax, AUC0-t and AUC0-∞ were 98.78%, 103.33% and 103.08%, respectively, while the 95% upper confidence bound values were all <0. These results all met the bioequivalence criteria for highly variable drugs. All adverse events were mild and transient.ConclusionIn this study, the generic formulation of valsartan 80 mg capsule was considered to be bioequivalent to the reference product under both fasting and fed conditions, and satisfied the requirements for marketing in China.NMPA Registration NoCTR20181422.

Bioavailability and swallowability of an age-appropriate, delayed-release mesalamine formulation in healthy volunteers.

Objective: Delayed-release mesalamine 400 mg capsules containing four 100 mg tablets have been developed for children with ulcerative colitis who have difficulty swallowing. Bioavailability of the mesalamine capsules was compared with existing mesalamine tablets in healthy adults, and the effect of food on bioavailability from mesalamine capsules was determined. Tablet swallowability in healthy children was evaluated.Methods: In the open-label, replicate-treatment, single-dose, crossover, comparative bioavailability study, healthy adult volunteers were randomized to one of four treatment sequences to receive mesalamine 400 mg tablets (fasted) twice, mesalamine 400 mg capsules (fasted) twice, and a mesalamine 400 mg capsule (with food) once, with ≥7 days between treatments. Pharmacokinetic (PK) parameters were calculated and analyzed using the reference-scaled average bioequivalence procedure. In the open-label, single-dose swallowability study, healthy children aged 5–11 years were asked to swallow eight placebo tablets identical to those contained in two mesalamine capsules.Results: In the bioavailability study (n=160), mesalamine capsules and tablets in fasted volunteers exhibited similarly delayed absorption and were shown to be bioequivalent; statistical parameters calculated from PK values met the criteria for bioequivalence. A slight increase in mesalamine bioavailability was observed with food administration, but the delayed-release performance of the capsules was not affected. Overall safety profiles between capsules and tablets were similar. In the swallowability study (n=60), the majority of children swallowed eight placebo tablets, with slight variability between age groups.Conclusion: Evaluation of PK parameters confirmed mesalamine capsules are bioequivalent to mesalamine tablets. Mesalamine capsules were well tolerated, can be administered with or without food, and are an age-appropriate product for children.

Controlling type I error in the reference-scaled bioequivalence evaluation of highly variable drugs.

Reference-scaled average bioequivalence (RSABE) approaches for highly variable drugs are based on linearly scaling the bioequivalence limits according to the reference formulation within-subject variability. RSABE methods have type I error control problems around the value where the limits change from constant to scaled. In all these methods, the probability of type I error has only one absolute maximum at this switching variability value. This allows adjusting the significance level to obtain statistically correct procedures (that is, those in which the probability of type I error remains below the nominal significance level), at the expense of some potential power loss. In this paper, we explore adjustments to the EMA and FDA regulatory RSABE approaches, and to a possible improvement of the original EMA method, designated as HoweEMA. The resulting adjusted methods are completely correct with respect to type I error probability. The power loss is generally small and tends to become irrelevant for moderately large (affordable in real studies) sample sizes.

Pharmacokinetics and bioequivalence of low-dose clopidogrel in healthy Chinese volunteers under fasted and fed conditions

Clopidogrel is an antiplatelet drug whose performance at a low dose (25 mg) have not been evaluated in Chinese patients, who may be subject to different effects from Caucasians. We carried out this evaluation and compared a generic (Taijia) and a reference drug (Plavix®). We evaluated Taijia and Plavix® in 128 subjects, with 64 in a fasted state and 64 receiving a high-fat diet, and computed Cmax, AUC0-∞, and AUC0-t. Reference-scaled average bioequivalence (RSABE) methods and average bioequivalence (ABE) methods were used, and adverse events were assessed. Average maximum plasma concentrations (Cmax) of clopidogrel were significantly greater after 25 mg dose under fed conditions compared to fasted. Reference-scaled Cmax, AUC0-t, and AUC0-∞ were higher than the 0.294 cutoff during fasted, meeting RSABE criteria. Under fed conditions, SWR for AUC0-t and AUC0-∞ were lower than 0.294, permitting use of ABE. The 90% confidence intervals for AUC0-t and AUC0-∞ indicated bioequivalence. Pharmacokinetic parameters differed between fasted and fed states. The generic product was bioequivalent to the reference drug, and was safe and well tolerated. This suggests that they can be used interchangeably in a clinical setting.

Evaluation of reference-scaled average bioequivalence of two oral formulations ofabiraterone acetate in healthy Chinesesubjects .

This study was designed to evaluate the pharmacokinetic (PK) properties and bioequivalence (BE) of two 250-mg tablet formulations of abiraterone acetate: a newly developed generic formulation (test) and a branded formulation (reference) in healthy adult Chinese subjects under fasted (n = 40) and fed (n = 40) conditions. The comparison was performed using a single-dose, open, randomized, and four-way replicate study. The concentration of abiraterone in blood samples taken over 48 hours was determined by liquid chromatography tandem mass spectrometry (LC-MS/MS). To assess the BE of the test and reference formulations, confidence intervals (CI, 90%) for the peak plasma concentration (Cmax) and area under the concentration-time curves (AUC0-t and AUC0-∞) were calculated using the reference-scaled average bioequivalence (RSABE) method. The results showed that the 90% CIs for the ratios of Cmax, AUC0-t, and AUC0-∞ in the fasted study were 90.14-114.11, 93.96-115.07, and 93.72-113.331, respectively. For the fed study, the 90% CIs were 81.83-102.51, 91.51-104.89, and 91.46-104.58, respectively. In conclusion, the tested 250-mg abiraterone tablets were bioequivalent to 250-mg Zytiga tablets (reference) under both fasted and fed conditions. In addition, food intake increased the systemic exposure and Cmax of abiraterone by 3-fold and 7-fold, respectively. .

PRINCIPLES OF STATISTICAL EVALUATION OF BIOEQUIVALENCE STUDIES IN THE CONTEXT OF CURRENT REGULATORY REQUIREMENTS AND LEGAL ACTS

The article analyses regulatory documents and requirements for statistical principles of planning and evaluation of results of bioequivalence studies. It describes current statistical approaches to bioequivalence evaluation and relevant recommendations for the planning of studies of conventional medicinal products, medicinal products with a narrow therapeutic range, and analogues of endogenous compounds. The article analyses such statistical approaches as average Bioequivalence (ABE), Average Bioequivalence with Expanding Limits (ABEL), Reference-Scaled Average Bioequivalence (RSABE). It describes specific aspects of statistical analysis of insufficiently studied medicinal products. The article also describes acceptable algorithms of planning and performing two-stage bioequivalence study designs, since such studies call for multiple testing of the bioequivalence hypothesis which leads to an increased probability of type i error (consumer risk). The article offers recommendations for the choice of statistical approaches and describes some aspects of statistical analysis methods depending on the design of the study and the type of generic medicines.

Drug Interchangeability of Generic and Brand Products of Fixed Dose Combination Tablets of Sofosbuvir and Ledipasvir (400/90mg): Employment of Reference Scaled Average Bioequivalence Study on Healthy Egyptian Volunteers.

The purpose of this study was to apply the reference-scaled average bioequivalence (RSABE) approach to evaluate the bioequivalence and to investigate the pharmacokinetic properties of two formulations of fixed dose combination (FDC) tablet of sofosbuvir (SOF) and ledipasvir (LED) (400/90mg) in 36 healthy Egyptian volunteers. The study was performed in single-dose, randomized-sequence, open-label, reference-replicated, 3-period crossover design (RTR, TRR, RRT), with a washout period of 2weeks. A rapid and simple LC-MS/MS method was developed and validated for the simultaneous estimation of SOF and LED using eplerenone as an internal standard (IS). The results showed that the 90% confidence intervals (CIs) for natural log-transformed ratios of Cmax, AUClast and AUC∞ of SOF (89.95-115.31, 98.77-109.75 and 98.79-109.75) were within the RSABE acceptance limits. The 90% CIs for natural log-transformed ratios of Cmax and AUClast of LED (87.33-115.15 and 83.82-112.26) were within the FDA bioequivalence limits (80.00-125.00). In addition, the in vitro dissolution study was done and both formulations released>85% of drug within 15min in the proposed dissolution medium. In conclusion, bioequivalence between the two fixed-dose combination products was demonstrated for both active ingredients.

Risk-Based Bioequivalence Recommendations for Antiepileptic Drugs.

This review summarizes the current FDA practice in developing risk- and evidence-based product-specific bioequivalence guidances for antiepileptic drugs (AEDs). FDA's product-specific guidance (PSG) for AEDs takes into account the therapeutic index of each AED product. Several PSGs for AEDs recommend fully replicated studies and a reference-scaled average bioequivalence (RS-ABE) approach that permit the simultaneous equivalence comparison of the mean and within-subject variability of the test and reference products. The PSGs for AEDs published by FDA reflect the agency's current thinking on the bioequivalence studies and approval standards for generics of AEDs. Bioequivalence between brand and generic AED products demonstrated in controlled studies with epilepsy patients provides strong scientific support for the soundness of FDA bioequivalence standards.