Pharmacokinetics of Generic Pediatric Dolutegravir Dispersible Tablet in Thai Young Children Living With HIV Weighing Below Twenty Kilograms.

INTRODUCTION: Dolutegravir (DTG) dispersible tablet (DTG-DT) is a pediatric-friendly formulation. We aimed to describe the pharmacokinetics and virologic responses of generic DTG-DT in children weighing <20 kg. METHODS: Children living with HIV-1 and <7 years of age weighing 6 to <20 kg were eligible. A generic 10-mg scored DTG-DT was administered to children using 3 weight bands (WB): WB1 (6 to <10 kg), WB2 (10 to <14 kg) and WB3 (14 to <20 kg), at doses of 20 mg (higher than World Health Organization recommendation of 15 mg), 20 mg and 25 mg, respectively. Steady-state intensive pharmacokinetics (PK) was performed in fasting condition with blood sampling at predose and 1, 2, 3, 4, 6 and 24 hours postdose. DTG PK parameters were estimated using a noncompartmental analysis, and DTG trough concentrations (C 24 ) and 24-hour area under the concentration-time curve were calculated. Comparisons were made with ODYSSEY and IMPAACT 2019. And 90% effective concentration of 0.32 mg/L was used as a reference individual DTG C 24 concentration. RESULTS: From August 2021 to March 2023, 29 Thai children with a median (interquartile range) age of 3.2 (1.5-4.8) years were enrolled; 8 in WB1, 9 in WB2 and 12 in WB3. All children were treatment experienced and 59% had HIV RNA <200 copies/mL. Overall geometric mean (coefficient of variation percentage) DTG C 24 was 1.0 (46%) mg/L [WB1, 0.9 (53%); WB2, 0.9 (27%); WB3, 1.2 (51%)]. Geometric mean (coefficient of variation percentage) 24-hour area under the concentration-time curve was 83.2 (24%) mg h/L [WB1, 84.3 (31%); WB2, 76.9 (16%); WB3, 87.6 (25%)]. At weeks 24 and 48, 90% and 92% of participants had plasma HIV RNA <200 copies/mL. CONCLUSIONS: Generic DTG-DT provided adequate drug exposure in children weighing 6 to <20 kg. The exploratory dose of DTG 20 mg for children weighing 6 to <10 kg showed similar PK parameters to World Health Organization doses in the other WB.

Pharmacokinetics and Safety of Estradiol Valerate Tablet and Its Generic: A Phase 1 Bioequivalence Study in Healthy Chinese Postmenopausal Female Subjects.

Purpose: Estradiol valerate (Progynova®) is used as hormone therapy to supplement estrogen deficiency. This study aimed to assess the bioequivalence of an estradiol valerate tablet and its generic form, under fasting and fed conditions. Methods: A randomized, open-label, single-dose, 2-period crossover study was conducted on healthy postmenopausal Chinese female volunteers under fasting and fed conditions. For each period, the subjects received either a 1 mg tablet of estradiol valerate or its generic. Blood samples were collected before dosing and up to 72 hours after administration. Plasma levels of total estrone, estradiol, and unconjugated estrone were quantified using a validated liquid chromatography-tandem mass spectrometry method. Results: A total of 54 volunteers were enrolled in this study. The primary pharmacokinetic parameters, including Cmax, AUC0-t, and AUC0-∞, were similar for the two drugs under both fasting and fed conditions, with 90% confidence intervals for the geometric mean ratios of these parameters, all meeting the bioequivalence criterion of 80-125%. A total of 48 adverse events (AEs) were reported in the fed study compared with 24 AEs in the fasting study. Conclusion: Estradiol valerate and its generic form were bioequivalent and well tolerated under both fasting and fed conditions.

Establishing Virtual Bioequivalence and Clinically Relevant Specifications for Omeprazole Enteric-Coated Capsules by Incorporating Dissolution Data in PBPK Modeling.

Currently, Biopharmaceutics Classification System (BCS) classes I and III are the only biological exemptions of immediate-release solid oral dosage forms eligible for regulatory approval. However, through virtual bioequivalence (VBE) studies, BCS class II drugs may qualify for biological exemptions if reliable and validated modeling is used. Here, we sought to establish physiologically based pharmacokinetic (PBPK) models, in vitro-in vivo relationship (IVIVR), and VBE models for enteric-coated omeprazole capsules, to establish a clinically-relevant dissolution specification (CRDS) for screening BE and non-BE batches, and to ultimately develop evaluation criteria for generic omeprazole enteric-coated capsules. To establish omeprazole's IVIVR based on the PBPK model, we explored its in vitro dissolution conditions and then combined in vitro dissolution profile studies with in vivo clinical trials. The predicted omeprazole pharmacokinetics (PK) profiles and parameters closely matched the observed PK data. Based on the VBE results, the bioequivalence study of omeprazole enteric-coated capsules required at least 48 healthy Chinese subjects. Based on the CRDS, the capsules' in vitro dissolution should not be < 28%-54%, < 52%, or < 80% after two, three, and six hours, respectively. Failure to meet these dissolution criteria may result in non-bioequivalence. Here, PBPK modeling and IVIVR methods were used to bridge the in vitro dissolution of the drug with in vivo PK to establish the BE safety space of omeprazole enteric-coated capsules. The strategy used in this study can be applied in BE studies of other BCS II generics to obtain biological exemptions and accelerate drug development.

Therapeutic-driven framework for bioequivalence assessment of complex topical generic drug products.

Despite the continuous research on understanding how topical drugs and the skin interact, the development of a topical generic product remains a challenge. Due to their local action effect rather than systemic, establishing suitable frameworks for documenting bioequivalence between reference and test formulations is anything but straightforward. In previous years, clinical endpoint trials were considered the gold standard method to demonstrate bioequivalence between topical products. Nevertheless, significant financial and time resources were required to be allocated owing to the inherent complexity of these studies. To address this problem, regulatory authorities have begun to accept alternative approaches that could lead to a biowaiver, avoiding the need for clinical endpoint trials. These alternatives encompass various in vitro and/or in vivo techniques that have been analysed and the benefits and drawbacks of each method have been considered. Furthermore, other factors like the integration of a quality by design framework to ensure a comprehensive understanding of the product and process quality attributes have also been taken into account. This review delves into international regulatory recommendations for semisolid topical products, with a focus on those established by the European Medicines Agency, as well as the Food and Drug Administration. Both approaches were carefully examined, discussing aspects such as acceptance criteria, sample size, and microstructure evaluation. Additionally, novel and innovative therapeutic-driven approaches based on in vitro disease models for the rapid and effective development of topical generic products are presented.

Pharmacokinetic Bioequivalence and Safety Assessment of Two Venlafaxine Hydrochloride Extended-Release Capsules in Healthy Chinese Subjects Under Fed Conditions: A Randomized, Open-Label, Single-Dose, Crossover Study.

BACKGROUND AND OBJECTIVE: Venlafaxine hydrochloride extended-release (ER) capsules are commonly used to treat depression and anxiety disorders. Evaluation of the bioequivalence of generic formulations with reference products is essential to ensure therapeutic equivalence. The objective of this study was to evaluate the bioequivalence, safety, and tolerability of Chinese-manufactured venlafaxine hydrochloride extended-release capsules compared with USA-manufactured EFFEXOR® XR in healthy Chinese volunteers under fed conditions. METHODS: A randomized, open-label, single-dose, crossover study was conducted. Subjects were randomly assigned to receive the test formulation (one 150-mg ER capsule manufactured in China) or the reference formulation (one 150-mg ER capsule manufactured in the USA). The bioequivalence of the two drugs was assessed using the area under the plasma concentration-time curve from time zero to the last sampling time (AUC0-t) and the maximum observed concentration (Cmax). RESULTS: A total of 28 subjects were enrolled and randomly assigned to receive a single dose of either the test or reference capsule. All the subjects completed the study and were included in the pharmacokinetic (PK) and safety analyses. The mean AUC0-t and Cmax of venlafaxine and its active metabolite O-desmethylvenlafaxine were comparable between the test and reference products with both parameters close to 100% and the corresponding 90% confidence intervals within the specified 80-125% bioequivalence boundary. Safety was also assessed between the two products and all adverse events (AEs) in this study were mild in severity. CONCLUSIONS: Both the test and reference venlafaxine hydrochloride ER capsules were bioequivalent and showed a similar safety and tolerability profile in the population studied. CLINICAL TRIALS REGISTRATION: This study was registered at the Drug Clinical Trial Registration and Information Publicity Platform ( http://www.chinadrugtrials.org.cn/index.html ) with registration number CTR20211243, date: June 1, 2021.

Tramadol/Diclofenac Fixed-Dose Combination for Acute Pain Management: Bioavailability Assessment of a Generic Product.

The multimodal analgesia strategy for acute pain involves using 2 or more analgesic medications with distinct mechanisms of action. This study assessed the bioavailability and tolerability of 2 tramadol hydrochloride (50 mg)/diclofenac sodium (50 mg) fixed-dose combination formulations under fed conditions to attend the Brazilian regulatory requirements for generic product registration. An open-label, randomized, single-dose, 2-period, 2-way crossover trial was conducted, including healthy subjects of both sexes. Subjects received a single dose of either the test or reference formulation of tramadol/diclofenac fixed-dose combination tablets with a 7-day washout period. Blood samples were collected up to 36 hours after dosing for tramadol and 12 hours for diclofenac and quantified using a validated liquid chromatography-tandem mass spectrometry method. Of 56 subjects enrolled, 53 completed the study. The 90% confidence intervals for maximum plasma concentration and area under the concentration-time curve from time 0 to the last quantifiable concentration were within acceptable bioequivalence limits of 80%-125%. Considering the results presented in this study, the test formulation is bioequivalent to the reference formulation and could be interchangeable in medical practice.

Pharmacokinetics and Bioequivalence of Fixed-Dose Combination of Simvastatin and Ezetimibe Tablets: A Randomized, Crossover, Open-Label Study in Healthy Volunteers.

The current study aimed to evaluate the bioequivalence of a new generic combination of simvastatin and ezetimibe with the reference formulation. An open-label, randomized, 3-period, 3-sequence, crossover study, including 60 healthy volunteers, was implemented. Participants received the test and reference formulation, each containing 20 mg of simvastatin and 10 mg of ezetimibe as a single-dose tablet, separated by a minimum of 2-week washout periods. Blood samples were collected for 20 time points from predose to 72 hours after the dose. The total ezetimibe assay was carried out using a validated liquid chromatography-tandem mass spectrometry, while unconjugated ezetimibe, simvastatin, and simvastatin ß-hydroxy acid determination was done via a validated ultra-performance liquid chromatography-tandem mass spectrometry. Each assay was preceded by a liquid-liquid extraction step. The pharmacokinetic parameters were derived using noncompartmental analysis and then compared between the reference and test formulations via a multivariate analysis of variance. No statistical difference was found in under the concentration-time curve from time 0 to the last quantifiable concentration and maximum concentration of unconjugated ezetimibe, total ezetimibe, and simvastatin between the reference and test formulations. The 90% confidence intervals of unconjugated ezetimibe, total ezetimibe, and simvastatin natural log-transformed under the concentration-time curve from time 0 to the last quantifiable concentration, and maximum concentration were in the range of 80%-125% as per the bioequivalence acceptance criteria. Therefore, the test formulation was bioequivalent to the reference formulation.

Evaluating gender effect in the generic bioequivalence studies by physiologically based pharmacokinetic modeling - A case study of dextromethorphan modified release tablets.

The United States Food and Drug Administration guidelines for the bioequivalence (BE) testing of the generic drug products suggests that there should be an equal proportion of male and female population in the BE study. Despite this requirement, many generic drug companies do not maintain the suggested proportion of female population in their studies. Several socio-economic and cultural factors lead to lower participation of the females in the BE studies. More recently, the regulatory agencies across the globe are requesting the generic drug companies to demonstrate the performance of their drug products in the under-represented sex via additional studies. In this work, we describe the case of Dextromethorphan modified release tablets where the gender effect on the product performance was evaluated by physiologically based pharmacokinetic (PBPK) modeling approach. We have compared the drug product's performance by population simulations considering four different scenarios. The data from all-male population (from in house Pharmacokinetic [PK] BE studies) was considered as a reference and other scenarios were compared against the all-male population data. In the first scenario, we made a comparison between all-male (100% male) vs all-female (100% female) population. Second scenario was as per agency's requirements-equal proportion of male and female in the BE study. As an extreme scenario, 100% male vs 30:70 male:female was considered (higher females than males in the BE studies). Finally, as a more realistic scenario, 100% male versus 70:30 male:female was considered (lower females than males in the BE studies). Population PK followed by virtual BE was employed to demonstrate the similarity/differences in the drug product performance between the sexes. This approach can be potentially utilized to seek BE study waivers thus saving cost and accelerating the entry of the generic products to the market.

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.

BACKGROUND AND OBJECTIVE: 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. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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. TRIAL REGISTRATION: Clinicaltrials, ChiCTR2300071630 (retrospectively registered in 19/05/2023).

Comparative Bleeding Risk of Brand Vs Generic Rivaroxaban in Elderly Inpatients with Atrial Fibrillation.

Objective: Atrial fibrillation (AF) is the most common abnormal heart rhythm in elderly patients. Rivaroxaban has been widely used for stroke prevention. The anticoagulant response to rivaroxaban increases with age, which may make elderly patients susceptible to adverse outcomes resulting from small differences in bioavailability between generic and brand products. Methods: We designed a cohort study of ≥65-year-old inpatients with AF. Sociodemographic and laboratory measures of qualified patients who received brand or generic rivaroxaban for at least 72 hours at the study hospital from January 2021 to June 2023 were collected retrospectively. The primary outcome was the incidence of bleeding. Results: A total of 1008 qualifying patients were included for analysis, with 626 (62.1%) receiving brand rivaroxaban and 382 (37.9%) receiving generic rivaroxaban. After propensity score matching and weighting to account for confounders, the odds ratios comparing brand vs generic rivaroxaban (95% confidence intervals) for the bleeding was 1.15 (0.72-1.82). Results from subgroup analyses of patients with age ≥85, HAS-BLED score ≥ 3, containment of antiplatelet drugs, and female patients were consistent with the primary analysis. Conclusion: It provides evidence regarding the clinical safety outcome of generic rivaroxaban in the elderly AF population that may be particularly susceptible to adverse outcomes resulting from small allowable differences in pharmacokinetics.

In Vitro In Vivo Extrapolation and Bioequivalence Prediction for Immediate-Release Capsules of Cefadroxil Based on a Physiologically-Based Pharmacokinetic ACAT Model.

Physiologically based pharmacokinetic (PBPK) modeling is a mechanistic concept, which helps to judge the effects of biopharmceutical properties of drug product such as in vitro dissolution on its pharmacokinetic and in vivo performance. With the application of virtual bioequivalence (VBE) study, the drug product development using model-based approach can help in evaluating the possibility of extending BCS-based biowaiver. Therefore, the current study was intended to develop PBPK model as well as in vitro in vivo extrapolation (IVIVE) for BCS class III drug i.e. cefadroxil. A PBPK model was created in GastroPlus™ 9.8.3 utilizing clinical data of immediate-release cefadroxil formulations. By the examination of simulated and observed plasma drug concentration profiles, the predictability of the proposed model was assessed for the prediction errors. Furthermore, mechanistic deconvolution was used to create IVIVE, and the plasma drug concentration profiles and pharmacokinetic parameters were predicted for different virtual formulations with variable cefadroxil in vitro release. Virtual bioequivalence study was also executed to assess the bioequivalence of the generic verses the reference drug product (Duricef®). The developed PBPK model satisfactorily predicted Cmax and AUC0-t after cefadroxil single and multiple oral dose administrations, with all individual prediction errors within the limits except in a few cases. Second order polynomial correlation function obtained accurately predict in vivo drug release and plasma concentration profile of cefadroxil test and reference (Duricef®) formulation. The VBE study also proved test formulation bioequivalent to reference formulation and the statistical analysis on pharmacokinetic parameters reported 90% confidence interval for Cmax and AUC0-t in the FDA acceptable limits. The analysis found that a validated and verified PBPK model with a mechanistic background is as a suitable approach to accelerate generic drug development.

Physiologically based absorption modeling to predict the bioequivalence of two apixaban formulations.

The equivalence of absorption rates and extents between generic drugs and their reference formulations is crucial for ensuring therapeutic comparability. Bioequivalence (BE) studies are widely utilized and play a pivotal role in substantiating the approval and promotional efforts for generic drugs. Virtual BE simulation is a valuable tool for mitigating risks and guiding clinical BE studies, thereby minimizing redundant in vivo BE assessments. Herein, we successfully developed a physiologically based absorption model for virtual BE simulations, which precisely predicts the BE of the apixaban test and reference formulations. The modeling results confirm that the test and reference formulations were bioequivalent under both fasted and fed conditions, consistent with clinical studies. This highlights the efficacy of physiologically based absorption modeling as a powerful tool for formulation screening and can be adopted as a methodological and risk assessment strategy to detect potential clinical BE risks.

Apixaban Pharmacokinetics and Bioequivalence of Two Tablet Formulations: A Randomized, Open-Label, Crossover Study, Fasting Condition in Healthy Indonesian Volunteers.

The present study aimed to assess the bioequivalence of a new apixaban generic with reference formulation. Twenty-six healthy volunteers were recruited for an open-label, balanced, randomized, 2-treatment, 2-sequence, 2-period, single oral dose study. Following overnight fasting, each volunteer received 5 mg of apixaban test and reference formulations as single doses, separated by a 1-week washout period. Twenty blood samples were collected at predose and multiple time points between 0.5 and 72 hours after dosing. A validated ultra-performance liquid chromatography-tandem mass spectrometry detection method following a protein precipitation step was implemented to determine apixaban concentrations. Noncompartmental analysis was used to derive the pharmacokinetic parameters, which were then compared between the test and reference products using a multivariate analysis of variance. The pharmacokinetic parameters of the test product were not statistically different from the reference product, and the 90% confidence intervals of apixaban natural log-transformed area under the concentration-time curve from time 0 to infinity, area under the concentration-time curve from time 0 to the last measurable concentration, and maximum concentration were within 80%-125% based on the bioequivalence acceptance range criteria. The test and reference formulations of apixaban are bioequivalent in healthy subjects under fasting conditions.

A crossover study to evaluate the pharmacokinetics and bioequivalence of hydroxychloroquine tablets in healthy Chinese subjects.

AIMS: Hydroxychloroquine (HCQ) has a high variability and a long half-life in the human body. The purpose of this study was to evaluate the bioequivalence of a generic HCQ tablet (test preparation) versus a brand HCQ tablet (reference preparation) under fasting and fed conditions in a crossover design. MATERIALS AND METHODS: This was an open-label, two-period randomized, single-dose, crossover study in 47 healthy Chinese subjects who were sequentially and randomly allocated either to the fed group (high-fat meal; n = 23) or the fasting group (n = 24). Participants in each group were randomized to the two arms to receive either a single 200-mg dose of the test preparation or a 200-mg dose of the reference preparation. The application of the two preparations in each patient was separated by a 28-day washout period, regarded as sufficiently long to avoid significant interference from residual drug in the body. Whole blood samples were collected over 72 hours after drug administration. RESULTS: A total of 23 subjects completed both the fed and the fasting parts of the trial. There were no significant differences in Cmax, AUC0-72h, and T1/2 between the test and reference preparation (p < 0.05). Food had no significant effect on Cmax and T1/2 (p < 0.05), but AUC0-72h values were significantly reduced under fed condition compared to fasting condition (p < 0.05). The 90% confidence intervals (CIs) for the geometric mean ratios (GMRs) of Cmax and AUC0-72h were 0.84 - 1.05 and 0.89 - 0.98 in the fed study, and 0.97 - 1.07 and 0.97 - 1.05 in the fasting study, respectively. The carryover effect due to non-zero blood concentrations resulted in higher AUC0-72h values in the second period for both test and reference formulations and had no effect on the statistical results. No serious adverse events were reported. CONCLUSION: The investigation demonstrated that the test and reference preparations are bioequivalent and well tolerated under both fasting and fed conditions in healthy Chinese subjects.

Comparison of solubility profiles for pioneer and generic monensin premixes in biorelevant simulated intestinal fluid based on shake flask extractions.

In the United States, a generic Type A medicated article product can gain the FDA approval by demonstrating bioequivalence (BE) to the pioneer product by successfully conducting a blood level, pharmacodynamic, or clinical BE study. A biowaiver can be granted based on several criteria, assuming the dissolution of the test and reference products represents the only factor influencing the relative bioavailability of both products. Monensin is practically insoluble in H2O per the USP definition. Previously published data from a comparison study of monensin dissolution profiles from the pioneer product and four generic products using biorelevant media showed that generic monensin products demonstrated different dissolution profiles to the pioneer product in these USP biorelevant rumen media. This follow-up study compared the solubility profiles in simulated intestinal fluid (cFaSSIF, pH 7.5) for the pioneer product and four generic products. The generic monensin products demonstrated different in vitro dissolution profiles to the pioneer product in biorelevant media. The differences demonstrated in solubility and dissolution profiles are of concern regarding the potential efficacy of generic monensin in cattle. There are also additional concerns for the potential development of Eimeria resistance in cattle receiving a sub-therapeutic dose of monensin from a less soluble generic product.

Evaluation of Biological Equivalence for Generic Tulathromycin Injections in Cattle.

The recent expiration of patents for the antibiotic tulathromycin has led to a significant increase in the number of generic tulathromycin products (GTPs) available. This study aims to evaluate the bioequivalence of four GTPs, which experienced a rapid increase in market share. The bioequivalence was evaluated by performing pharmacokinetic assessments. The four selected GTPs (Tulaject, Tulagen, Toulashot, and T-raxxin) were compared with the reference product, Draxxin. A dose of 2.5 mg/kg.bw/day was administered via subcutaneous injection, and blood samples were collected 460 times from 20 Holstein cattle. Plasma concentrations of tulathromycin were measured over time using LC-MS/MS analysis. Bioequivalence was evaluated using a statistical program for pharmacokinetic parameters, including the area under the concentration time curve (AUC) and the maximum plasma concentration (Cmax). The bioequivalence was considered proven if the difference between the test and reference products was within 20% for both AUC and Cmax. The results showed that the confidence interval (CI, 90%) for both AUC and Cmax values was within the 80~120% range, demonstrating the bioequivalence of the four GTPs compared to Draxxin. This study provides evidence for the bioequivalence of the selected GTPs, contributing to their validation for use as effective antibiotics.

Bioequivalence Evaluation of Topical Metronidazole Products Using Dermal Microdialysis in New Zealand Rabbits.

Comparative assessment of cutaneous pharmacokinetics (cPK) by dermal microdialysis (dMD) appears to be suitable to evaluate the bioequivalence (BE) of topical dermatological drug products applied to the skin (TDDPs). Although dMD studies in the literature have reported inconclusive BE assessments, we have addressed several methodological deficiencies to improve dMD's capability to assess BE between reference (R) and approved generic (referred to as test (T)) gel and cream products of metronidazole (MTZ). The 90% confidence interval (CI) of the geometric mean ratios for the Ln(AUC0-24) and Ln(Cmax) endpoints was centered within the BE limits of 80-125%. The CIs extended outside this range as the proof-of-principle study was not statistically powered to demonstrate BE (N = 7 rabbits). A power analysis suggests that, with the variability observed in this study, 21 rabbits for the cream and 11 rabbits for the gel would be sufficient to support an evaluation of BE with the 2 probe replicates we used, and only 10 and 5 rabbits would be sufficient to power the study for the cream and gel, respectively, if 4 probe replicates are used for each treatment per rabbit. These results indicate that dMD when properly controlling variables can be used to support BE assessments for TDDPs.

Biopharmaceutics Risk Assessment-Connecting Critical Bioavailability Attributes with In Vitro, In Vivo Properties and Physiologically Based Biopharmaceutics Modeling to Enable Generic Regulatory Submissions.

Quality risk assessment following ICH Q9 principles is an important activity to ensure optimal clinical efficacy and safety of a drug product. Typically, risk assessment is focused on product performance wherein critical material attributes, formulation variables, and process parameters are evaluated from a manufacturing perspective. Extending ICH Q9 principles to biopharmaceutics risk assessment to identify factors that can impact in vivo performance is an upcoming area. This is evident by recent regulatory trends wherein a new term critical bioavailability attributes (CBA) has been coined to identify such factors. Although significant work has been performed for biopharmaceutics risk assessment for new molecules, there is a need for harmonized biopharmaceutics risk assessment workflow for generic submissions. In this manuscript, we attempted to provide a framework for performing biopharmaceutics risk assessment for generic regulatory submissions. A detailed workflow for performing biopharmaceutics risk assessment includes identification of initial CBA (iCBA), their confirmatory evaluation followed by definition of the control strategy. Tools for biopharmaceutics risk assessment, i.e., bio-discriminatory dissolution method and physiologically based biopharmaceutics modeling (PBBM) were discussed from a practical perspective. Furthermore, a case study for CBA evaluation using PBBM modeling for an extended-release product for regulatory submission has been described using the proposed workflow. Finally, future directions of integrating CBA evaluation, biopharmaceutics risk assessment to the FDA Knowledge Aided Structured Assessment (KASA) initiative, the necessity of risk assessment templates, and knowledge sharing between industry and academia are discussed. Overall, the work described in this manuscript can facilitate and provide guidance for biopharmaceutics risk assessment for generic submissions.

A single-dose, randomized crossover study in healthy Chinese subjects to evaluate pharmacokinetics and bioequivalence of two capsules of calcium dobesilate 0.5 g under fasting and fed conditions.

OBJECTIVES: To compare the rate and extent of absorption of a launched generic calcium dobesilate capsule versus the branded reference formulation under fasting and fed conditions in healthy Chinese subjects, and to assess their bioequivalence and tolerability. METHODS: This single-dose, open-label, randomized-sequence, 2-period crossover bioequivalence study was conducted on healthy Chinese volunteers aged 18 to 45 years. Subjects received a single 0.5 g dose of calcium dobesilate capsule under fasting or fed conditions, with a 3-day washout period between doses of the test (T) and reference (R) formulations. Blood samples were collected before and up to 24 hours after administration. The plasma concentration of calcium dobesilate was determined by a validated Liquid chromatography-tandem mass spectrometry method. Non-compartmental analysis was applied to identify the pharmacokinetic (PK) properties. The primary PK parameters including the maximal plasma concentration (Cmax), the area under the plasma concentration-time curve (AUC0-t), and the AUC extrapolated to infinity (AUC0-inf) were used for bioequivalence evaluation. RESULTS: The mean of PK parameters for T and R capsules under fasting (fed) condition were: Cmax, 13.57 (6.71) and 12.59 (7.25) µg/mL; AUC0-t, 97.32 (79.74) and 96.97 (80.71) h*µg/mL; AUC0-inf, 101.68 (88.01) and 101.64 (87.81) h*µg/mL. The 90% confidence intervals (CIs) of GMRs under fasting (fed) condition were: Cmax, 97.91%-116.62% (88.63%-96.53%); AUC0-t, 97.15%-104.00% (96.58%-101.39%); and AUC0-inf, 97.19%-102.89% (98.67%-103.99%). These 90% CIs were all within the bioequivalence range of 80%-125%. All adverse events were mild. CONCLUSION: In this study, the T calcium dobesilate 0.5 g capsule was bioequivalent to the reference product under both fasting and fed conditions. Taking food would slow down its rate and reduce its amount of absorption. Both formulations were generally well tolerated.

Bioequivalence Study of Ezetimibe Tablets After a Single Oral Dose of 10 mg in Healthy Japanese Subjects Under Fasting Conditions.

This study compared the pharmacokinetic and safety profiles between a new generic and a branded reference product of 10-mg ezetimibe (EZE) tablets in 24 healthy Japanese male volunteers under fasting conditions, obtaining sufficient evidence for the marketing approval of the new generic product. The bioequivalence study was conducted with an open-label, 2 × 2, single-dose, crossover design in which the test and reference products were administered to volunteers after fasting for ≥10 hours. Blood samples were collected 24 times before to 72 hours after the administration of the investigational drug. We evaluated the peak drug concentration and the area under the plasma concentration-time curve up to the last measured concentration of EZE, EZEG, and total EZE (EZE + ezetimibe glucuronide [EZEG]). The 90% confidence intervals of the geometric mean ratios for peak drug concentration and area under the plasma concentration-time curve up to the last measured concentration of the test and reference products fell within the bioequivalence limits of 0.80 to 1.25 for EZE, EZEG, and total EZE. The test and reference products were well tolerated, and no adverse events occurred during the study. The test product was bioequivalent to the reference product.