Bioequivalence Study Research Articles

Bioequivalence of Elagolix/Estradiol/Norethindrone Acetate Fixed-Dose Combination Product: Phase 1 Results in Healthy Pre- and Postmenopausal Women.

Fixed-dose combination (FDC) therapies can enhance patient convenience and adherence to prescribed treatment regimens. Elagolix is a novel oral gonadotropin-releasing hormone receptor antagonist approved for management of moderate to severe pain associated with endometriosis and heavy menstrual bleeding associated with uterine fibroids. Hormonal add-back therapy can attenuate the reversible hypoestrogenic effects of elagolix. An FDC formulation containing elagolix/estradiol (E2)/norethindrone acetate (NETA) 300/1/0.5mg as the morning dose and an elagolix 300mg capsule as the evening dose, were evaluated in 2 bioequivalence studies including the effects of food. Study 1 in premenopausal women assessed the bioavailability of the elagolix 300-mg capsule relative to the commercially available elagolix 300-mg tablet. Study 2 in postmenopausal women, elagolix/E2/NETA (300mg/1mg/0.5mg) FDC capsule was assessed relative to the elagolix 300-mg tablet coadministered with E2/NETA 1-mg/0.5-mg tablet, the regimen that was studied in Phase 3 uterine fibroid studies. Under fasting conditions, the test elagolix 300-mg capsule was bioequivalent to the reference elagolix 300-mg tablet. Under fasting conditions, the elagolix/E2/NETA FDC capsule was bioequivalent to the coadministered elagolix 300-mg tablet and E2/NETA 1/0.5-mg tablet. Following administration of elagolix/E2/NETA FDC capsule after a high-fat breakfast, elagolix mean maximum concentration (Cmax) and area under the plasma concentration-time curve (AUC) were 38% and 28% lower, relative to fasting conditions. NETA mean Cmax was 51% lower and AUC from time 0 to infinity was 20% higher, while baseline-adjusted total estrone mean Cmax and AUC were 46% and 14% lower, respectively. No safety concerns were identified. These results enabled bridging the elagolix/E2/NETA FDC capsule.

Pharmacokinetics of Nitazoxanide Dry Suspensions After Single Oral Doses in Healthy Subjects: Food Effects Evaluation and Bioequivalence Study.

Nitazoxanide (NTZ) is an effective antiparasitic drug with potent antiviral and antimicrobial activity. This randomized, open-label, 2-sequence, 2-period crossover trial was designed to evaluate the bioequivalence (BE) of the NTZ dry suspension in healthy subjects and investigated the effect of food intake on the pharmacokinetic (PK) properties of tizoxanide (an active metabolite of NTZ, TIZ). Sixty healthy Chinese subjects were enrolled and received a single dose of 500mg/25mL of preparations on days 1 and 4 under overnight fasting or fed conditions, respectively. The plasma concentration of TIZ was determined using high-performance liquid chromatography/tandem mass spectrometry. PK parameters were calculated using WinNonlin 8.2 and BE was evaluated using SAS 9.4. The 90% confidence intervals for the geometric mean ratio (test/reference) of maximum concentration (Cmax), the area under the curve from time 0 to the time of the last quantifiable concentration (AUC0-t), and the area under the curve from time 0 to extrapolation to infinity (AUC0-∞) were all within the equivalent interval of 80%-125%, compliant with BE requirements. In comparison with fasting, on taking the reference and test preparations of the NTZ dry suspension after a meal, the AUC0-t increased by 48.9% and 47.3%, respectively, the AUC0-∞ increased by 48.4% and 48.3%, respectively, and the post-meal Tmax was prolonged by 1.8-2hours. Our results demonstrate that the test and reference preparations were bioequivalent. High-fat meals significantly improve the degree of drug absorption and delay the rate of drug absorption.

LC-MS/MS method for quick detection of vonoprazan fumarate in human plasma: Development, validation and its application to a bioequivalence study.

A liquid chromatography-tandem mass spectrometry method with vonoprazan fumarate-d4 as a stable isotope-labeled internal standard was developed and validated aiming at quantification of vonoprazan fumarate in human plasma for a bioequivalence study. Chromatographic separation was achieved by acetonitrile one-step protein precipitation using a gradient elution of 0.1% formic acid aqueous solution and acetonitrile with a run time of 3.65 min. Detection was carried out on a tandem mass spectrometer in multiple reaction monitoring mode via a positive electrospray ionization interface. The multiple reaction monitoring mode of precursor-product ion transitions for vonoprazan fumarate and vonoprazan fumarate-d4 were m/z 346.0 → 315.1 and 350.0 → 316.0, respectively. The linear range was 0.150-60.000 ng/ml. This method was fully validated with acceptable results in terms of selectivity, carryover, lower limit of quantification, calibration curve, accuracy, precision, dilution effect, matrix effect, stability, recovery and incurred sample reanalysis. A successful application of this method was realized in the bioequivalence study of vonoprazan fumarate tablet (20 mg) among healthy Chinese volunteers.

Dissolution profile evaluation of selected brands of amoxicillin-clavulanate potassium 625 mg tablets retailed in Hawassa town, Sidama Regional State, Ethiopia

Poor quality amoxicillin-clavulanate potassium tablets have been recently discovered in generic drugs related to Augmentin-like medicines containing amoxicillin and clavulanic acid, as well as its derivatives containing falsified active ingredients. One of the most important dosage form characteristics are a detailed active pharmaceutical ingredients dissolution release profile evaluation obtained through dissolution testing. The dissolution test is used in the development of both brand-name and generic drugs. Prior to beginning bioequivalence studies, it is critical to compare the dissolution profiles of various pharmaceutical products. As a result, dissolution is a critical quality control parameter for drugs because it has a direct impact on absorption of pharmaceutical products. Dissolution profile evaluation of seven brands of amoxicillin-clavulanate potassium tablets is retailed in Hawassa town, Sidama Regional State, Ethiopia. The seven brands of amoxicillin-clavulanate potassium tablets were collected from Hawassa town, Sidama Regional State, Ethiopia. The dissolution study was conducted as per USP40-NF35. Then, the dissolution profile test results were compared by one-way ANOVA Dunnett’s test, model independent, and model dependent method. All of the included brand tablets complied with a single-point dissolution study specification. All brand tablets had similar dissolution profiles (p > 0.05), difference factor (f1) < 15%, and dissolution efficiency (≤10%\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$(\\le 10\\varvec{\\%}$$\\end{document}). However, the f2 (similarity factor) value justifies that all brand tablets were not within USFDA specification (≥\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\ge$$\\end{document}50%). The evaluated brands followed the Korsemeyer-Peppas followed by the Weibull curve models. All brand tablets passed the single point USP dissolution specification and the USFDA therapeutic interchangeability guideline. The similarity factor (f2), on the other hand, confirmed that none of the tested brand tablets were interchangeable with the innovator product. Therefore, researchers, national medicine regulatory bodies, and the manufacturer should conduct a properly designed dissolution test as proof of an in vitro bioequivalence study supported by in vivo bioavailability data.

Introducing an Artificial Neural Network for Virtually Increasing the Sample Size of Bioequivalence Studies

Sample size is a key factor in bioequivalence and clinical trials. An appropriately large sample is necessary to gain valuable insights into a designated population. However, large sample sizes lead to increased human exposure, costs, and a longer time for completion. In a previous study, we introduced the idea of using variational autoencoders (VAEs), a type of artificial neural network, to synthetically create in clinical studies. In this work, we further elaborate on this idea and expand it in the field of bioequivalence (BE) studies. A computational methodology was developed, combining Monte Carlo simulations of 2 × 2 crossover BE trials with deep learning algorithms, specifically VAEs. Various scenarios, including variability levels, the actual sample size, the VAE-generated sample size, and the difference in performance between the two pharmaceutical products under comparison, were explored. All simulations showed that incorporating AI generative algorithms for creating virtual populations in BE trials has many advantages, as less actual human data can be used to achieve similar, and even better, results. Overall, this work shows how the application of generative AI algorithms, like VAEs, in clinical/bioequivalence studies can be a modern tool to significantly reduce human exposure, costs, and trial completion time.

Volunteers in bioequivalence clinical trials: premises for participation. Part 2

The article presents the results of interviews with volunteers in order to study their motivation to participate in clinical trials of the bioequivalence phase, their experience of such participation, as well as opinions regarding the organization of clinical trials in the Russian Federation. The results of the study demonstrate a high level of interest among volunteers to regularly participate in bioequivalence studies due to their relative safety for health, as well as financial interest and comfortable organization of the research process. The article describes the socio-demographic profile of a “bioequivalence phase volunteer.”

In Vivo Bioequivalence Study of Drug: An Analysis of Bidding in Vietnam Period 2018 - 2022

To promote the development of bioequivalent drugs, the Ministry of Health of Vietnam has classified a separate bidding group for bioequivalent drugs. According to the results of bidding for bioequivalent drugs in the period 2018 - 2022 has achieved very encouraging results, the ratio of domestic bioequivalent drugs compared to foreign bioequivalent drugs winning bids is from 2.13 to 3.63 times higher. Regarding active pharmaceutical ingredients of bioequivalent drugs, bioequivalent drugs with the highest total winning value (including all dosage forms, concentrations,...) focus mainly on antibiotics (cefuroxime, cefixime,…), anti-diabetic drugs (gliclazide, metformin,...), high blood pressure drugs (amlodipine), antipyretic and pain relievers (paracetamol). The winning drug dosage forms are still mainly conventional dosage forms (tablets, film-coated tablets, capsules) and their active ingredients are almost single. In particular, several multi-component bioequivalence drugs have a large total winning value but do not belong to the pharmaceutical group on the list of mandatory bioequivalence test reports when registering the drug, such as the combination of Gliclazide + Metformin; Glibenclamide + Metformin; Glimepiride + Metformin. The trend of selecting pharmaceutical substances/groups of pharmaceutical substances that manufacturers focus on researching/registering bioequivalent drugs in Vietnam is focused on drugs on the list of drugs covered by health insurance.&#x0D;  

The bioequivalence study design recommendations for immediate-release solid oral dosage forms in the international pharmaceutical regulators programme participating regulators and organisations: differences and commonalities.

Bioequivalence (BE) studies are considered the standard for demonstrating that the performance of a generic drug product in the human body is sufficiently similar to that of its comparator product. The objective of this article is to describe the recommendations from participating Bioequivalence Working Group for Generics (BEWGG) members of the International Pharmaceutical Regulators Programme (IPRP) regarding the conduct and acceptance criteria for BE studies of immediate release solid oral dosage forms. A survey was conducted among BEWGG members regarding their BE recommendations and requirements related to study subjects, study design, sample size, single or multiple dose administration, study conditions (fasting or fed), analyte to be measured, selection of product strength, drug content, handling of endogenous substances, BE acceptance criteria, and additional design aspects. All members prefer conducting single dose cross-over designed studies in healthy subjects with a minimum of 12 subjects and utilizing the parent drug data to assess BE. However, differences emerged among the members when the drug's pharmacokinetics and pharmacodynamics become more complex, such that the study design (e.g., fasting versus fed conditions) and BE acceptance criteria (e.g., highly variable drugs, narrow therapeutic index drugs) may be affected. The survey results and discussions were shared with the ICH M13 Expert Working Group (EWG) and played an important role in identifying and analyzing gaps during the harmonization process. The draft ICH M13A guideline developed by the M13 EWG was endorsed by ICH on 20 December 2022, under Step 2.

Lacosamide extended-release capsules are bioequivalent to lacosamide immediate-release tablets: Pharmacokinetic observations and simulations

ObjectivesAssess the bioequivalence of lacosamide extended-release (XR) capsules and immediate-release (IR) tablets and answer real-world clinical questions regarding the use of lacosamide XR. MethodsAn open-label, randomized, two-treatment, two-sequence, oral comparative bioavailability study was conducted to assess the bioequivalence of two lacosamide formulations. Participants were randomized 1:1 to receive lacosamide XR capsules (400 mg once-daily) or IR tablets (200 mg twice-daily) in 1 of 2 sequences over 7-day periods. Primary outcome was the area under the lacosamide concentration-time curve over 24 h at steady-state (AUC0-τ,ss). Secondary outcomes were maximum (Cmax,ss) and minimum concentrations at steady-state (Cmin,ss). Bioequivalence was established when 90% confidence intervals (CIs) for geometric least square means ratios (GLSMs) were between 80% and 125%. Adverse events (AEs) and other safety outcomes were also assessed. Pharmacokinetic simulations, including adherent and partially adherent dosing scenarios with XR and IR formulations, modeled the clinical use of lacosamide XR. ResultsThirty-five healthy adult males were enrolled in the bioequivalence study. After 7 days of study drug, mean AUC0-τ,ss, Cmax,ss, and Cmin,ss values were similar between XR and IR formulations; all 90% CIs for GLSMs were between 80% and 125%. AEs were mild and no serious AEs or other clinically significant safety findings were observed. Pharmacokinetic simulations suggested that partial adherence affected formulations similarly; and the best strategy for switching formulations was to take the morning lacosamide IR dose followed by the evening lacosamide XR dose, as this resulted in the most consistent lacosamide plasma concentrations. ConclusionsOnce-daily lacosamide XR capsules were bioequivalent to twice-daily lacosamide IR tablets. Pharmacokinetic simulations indicated lacosamide XR and IR formulations were similarly affected by partial adherence, though once-daily dosing with lacosamide XR may offer clinical advantages, and formulations can be easily switched. These results support the use of lacosamide XR capsules as a once-daily alternative to lacosamide IR tablets.

Pharmacokinetic and bioequivalence study of two capecitabine tablets in Chinese patients with solid tumor cancer.

Capecitabine (CAP) is one of the fluoropyrimidine deoxynucleoside carbamates, which can be converted to 5-fluorouracil (5-FU) by thymine deoxynucleoside phosphorylase (dThdPase) to exert antitumor effects. The purpose of this study is to compare the pharmacokinetics (PK), bioequivalence (BE), and safety of two CAP tablets in Chinese patients with solid tumor cancer. The results showed that the geometric mean ratios (GMRs) of Cmax, AUC0-t and AUC0-∞ of CAP T/R reagent were 90.26%, 95.27%, and 95.07, respectively. The values and 90% confidence intervals (CI) of AUC0-t, AUC0-∞, and Cmax all fall within the range of 80.00-125.00%. In addition, a total of 22 subjects in this study had 30 adverse events, with an incidence of 45.83%, and there were no serious adverse events and adverse events that led to withdrawal from the trial.

APPROACHES ON SURROGATE METHODS FOR IN VIVO BIOEQUIVALENCE STUDY OF FORMULATED BILAYER TABLETS OF DOMPERIDONE AND ITOPRIDE

Objective: This study aims to provide a more efficient pathway for generic drug approval while maintaining the same level of therapeutic equivalence and safety as the reference product. This was based on the equivalence of in vitro evidence other than through expensive in vivo equivalence testing. Methods: Biowaiver and IVIVC are surrogate methods for in vivo bioequivalence studies. The Biowaiver test was done according to WHO, TRS992, 2015 Annex 7, Appendix 1, the recommendation for conducting and assessing comparative dissolution. IVIVC was done by the level A Convolution method. Innovator product was used as Ganaton OD for Itopride and Motilium for Domperidone to perform the comparison testing. Results: The similarity factor (F2) between the test and innovator product of Domperidone at pH 1.2 HCl, Acetate Buffer pH 4.5, and water was 79.51, 68.00, and 58.97 and the dissimilarity factor (F1) was 7.24, 8.05 and 11.01 respectively. From the IVIVC study by level A convolution method of Cmax, AUC, Tmax of Ganaton OD and formulated Itopride were found to be 409.16ng/ml, 5652.28 ngh/ml and 4h and 252.16ng/ml, 4601.12 ngh/ml and 12 h respectively. Conclusion: The F2 limit is 50-100 and F1 is 15 mentioned as per guidelines followed for the biowaiver test, which means the formulated domperidone is deemed equivalent to (Motilium) innovator of domperidone. The predictive error on the AUC of Itopride formulated was found to be 18.59 % which was within the limit of±20 %, demonstrating the therapeutic range.

(031) Bioequivalence Studies of Sildenafil Citrate Orodispersible Film Administered With and Without Water versus Viagra Film-Coated Tablets in Healthy Adult Male Volunteers

Abstract Introduction Orodispersible film (ODF) formulation offers ease of use, convenience of administration, and other advantages, especially for patients who have difficulty in swallowing or are on liquid restriction compared with conventional oral formulations for the treatment of erectile dysfunction. Objective These studies compared the bioequivalence of 50 mg sildenafil citrate ODF formulation (test drug) with the marketed 50 mg sildenafil citrate film-coated tablet (FCT) (Viagra; Pfizer, New York, NY) (reference drug), with and without water in 2 randomized cross-over studies. Methods Two randomized cross-over studies were conducted. The first study explored the bioequivalence of test drug administered with and without water compared with the reference drug with water. The second study investigated the bioequivalence of test drug, without water, compared with the reference drug with water. 42 healthy adult male volunteers started the first study and only 40 completed. While 80 subjects who were enrolled completed the second study. All the 120 subjects from both the studies were included for pharmacokinetic and bioequivalence analysis. All volunteers fasted for 10 hours pre-dose. A 1-day washout period between doses was observed. Blood samples were collected at regular intervals both before (up to 120 minutes before dosing) and after dosing (at different intervals up to 14 hours) dosing stages. Statistical analyses on pharmacokinetic parameters were performed. Safety and tolerability for both the formulations were evaluated. Results In the first study, bioequivalence was demonstrated for sildenafil citrate ODF administered with water when compared with the Viagra FCT. The ratios of adjusted geometric means (90% confidence interval (CI)) were maximum plasma concentration: 1.02 (94.91–108.78) and area under the plasma concentration-time curve: 1.09 (104.49–113.21) for sildenafil citrate ODF administered with water vs Viagra FCT. These ratios were within the bioequivalence acceptance range of 80% to 125%, indicating that the bioequivalence criteria were met. The pharmacokinetic parameters for the second study also demonstrated bioequivalence for sildenafil citrate ODF when administered without water compared with Viagra FCT. The ratios of adjusted geometric means (90% CI) were maximum plasma concentration: 1.02 (95.47–109.36) and area under the plasma concentration-time curve: 1.06 (103.42–108.40) for sildenafil citrate ODF administered without water vs Viagra FCT. Adverse events in both the studies occurred at similar rates for the 2 formulations and were mild in intensity and were expected from the known safety profile. Conclusions Sildenafil citrate ODF administered with and without water met bioequivalence criteria compared with Viagra FCT administered with water under fasted conditions in healthy adult male volunteers. These results suggest that the new ODF formulation can be used interchangeably with the marketed FCT formulation. Therefore, the new ODF formulation can be used as a suitable alternative to the conventional oral solid dosage form for the treatment of ED. Disclosure Yes, this is sponsored by industry/sponsor: Viatris Inc. Clarification: Industry initiated, executed and funded study. Any of the authors act as a consultant, employee or shareholder of an industry for: Viatris Inc.

Development of a New Bioequivalent Omeprazole Product.

Background and Objectives: The enteric form of omeprazole is one of the most commonly prescribed medications. Similarly to Europe, Kazakhstan relies on the localization of pharmaceutical drug production as one of its primary strategies to ensure that its population has access to affordable and good-quality medicines. This study comprehensively describes the technologically available development of bioequivalent delayed-release omeprazole. Materials and Methods: Various regimes and technological parameters were tested on laboratory- and production-scale equipment to establish a technical process where a functional and gastro-protective layer is essential. According to the ICH guidance on stability testing and Kazakhstan local rules, stability studies were conducted under conditions appropriate for climate zone II. The comparison of the rate and extent of absorption with subsequent assessment of the bioequivalence of the generic and reference drugs after a single dose of each drug at a dose of 40 mg was performed. Results: The quantitative and qualitative composition and technology of producing a new generic enteric form of omeprazole in capsules were developed and implemented at the manufacturing site of solid forms. Dissolution profiles in media with pH 1.2 and 6.8 were proven. During the accelerated six-month and long-term twelve-month studies, the developed formulation in both packaging materials at each control point passed the average weight and mass uniformity test, dissolution test, acid-resistance stage test, buffer stage test, impurity assay, and microbiological purity test and met all the specification criteria. A bioequivalence study in 24 healthy volunteers compared against the innovative drug showed the bioequivalency of the new generic system. The obtained values from the test and reference products were 1321 ± 249.0 ng/mL and 1274 ± 233 ng/mL for Cmax, 4521 ± 841 ng·h /mL and 4371 ± 695 ng·h /mL for AUC0-t, and 4636 ± 814 ng·h /mL and 4502 ± 640 ng·h /mL for AUC0-∞. Conclusions: Using affordable technologies, a bioequivalent generic delayed-release formulation of 20 and 40 mg omeprazole has been developed.

Pharmacokinetics and bioequivalence evaluation of two oral formulations of cotrimoxazole tablets in healthy Chinese volunteers under fasting conditions

This bioequivalence study was conducted to evaluate two oral formulations of cotrimoxazole tablets in healthy Chinese subjects. All 26 subjects recruited to this study were randomly and evenly classified into two groups and received a single dose (sulfamethoxazole: 400 mg and trimethoprim: 80 mg) of test cotrimoxazole tablets (generic drug) or reference cotrimoxazole tablets (branded drug). After a 7-day washout period, these subjects received one dose of reference drug or test drug. Blood samples were collected from participants before and up to 48 h after dosing to assess the concentration of sulfamethoxazole (SMX) and trimethoprim (TMP) in plasma and a plasma concentration-time curve was drawn. Then, the pharmacokinetics parameters were calculated accordingly. Our data revealed that there were no significant differences observed in the maximum plasma concentration (Cmax), area under the curve from time 0 to the last measurable concentration (AUC0-t), and area under the curve from time 0 to infinity (AUC0-∞) between the two formulations. For SMX, the 90% confidence intervals (CI) of the geometric mean ratio for Cmax, AUC0-t, and AUC0-∞ were 104.03-113.92%, 100.46-103.70%, and 100.41-103.81%, respectively. Similarly, for Trimethoprim (TMP), the 90% CI ranged from 98.54 to 106.95% for Cmax, from 99.31 to 107.68% for AUC0-t, and from 99.49 to 107.55% for AUC0-∞. Importantly, all these 90% CI values fell within the range of 80.00–125.00%, indicating that the test drug is bioequivalent to the reference drug. Furthermore, throughout the entire trial, no suspected serious adverse events were reported, indicating the safety profile of the newly developed generic cotrimoxazole. In summary, our study demonstrates that the newly developed generic formulation of cotrimoxazole is bioequivalent to the branded formulation under fasting conditions.

Biowaiver as a Bioequivalence Study Option

SCIENTIFIC RELEVANCE. Biowaiver is a procedure for establishing the bioequivalence of generic and reference products without in vivo studies. Regulatory requirements for this procedure, as described in a variety of documents, differ in certain features and aspects. These differences need to be analysed.AIM. The aim was to compare international and Russian regulatory approaches to the Biopharmaceutics Classification System-based biowaivers, provide recommendations on comparative dissolution testing, and outline opportunities for streamlining the regulatory framework of the Eurasian Economic Union (EAEU).DISCUSSION. In this article, the authors analyse biowaiver requirements and describe procedures for assessing the permeability and pH-dependent solubility of medicines, comparing dissolution profiles in various media that simulate the gastrointestinal environment, and interpreting test results. This paper shows the role of excipients in the solubility and permeability of an active substance.CONCLUSIONS. The authors recommend a methodological approach to the biowaiver procedure for replacing in vivo bioequivalence studies with in vitro tests under the current EAEU regulatory framework and list the characteristics of medicines that limit the applicability of the procedure. In conclusion, this article provides a rationale for harmonising the existing guidelines and requirements.

Development and Validation of Bioanalytical Method for Estimation of Rivaroxaban using RP-HPLC with Liquid liquid extraction in Human Blood Plasma and its application in Bioequivalence Study

Rivaroxaban is andirect acting oralanticoagulant and factor Xa inhibitor. A simple, selective, precise and rapid RP-HPLC method for estimation of Rivaroxaban (RIVA) in human blood plasma was developed and validated. The sample spike in plasma was extracted using liquid liquid extraction were extracted with the organic solvent ethyl acetate as organic solvent. Apixaban as an internal standard. The compounds were analysed by Agilent HPLC was used with control panel software using UV detector on a Inertsil ODS (250mm x 4.6mm ID;5μ) column with an Flow rate of 1.2mL/min, an isocratic mobile phase consisting of 0.02M Ammonium acetate buffer: Acetonitrile (70:30%v/v). Different sample pre-treatment techniques were evaluated, but Liquid Liquid extraction was found to be satisfactory, with good recovery values of 93.70% for RIVA. The developed method is validated by ICHM10 and USFDA guidelines over the concentration range of 5.00 to 200.00 ng/ml in human blood plasma with R² =0.9993. Within-day precisions and accuracy for RIVA were found in 0.36% to 4.73% and 92.58% to101.82% respectively. The validated RP-HPLC method has been used successfully for both preliminary pharmacokinetic studies and therapeutic drug monitoring

Study of bioequivalence of veterinary drugs “Pinpramil” and “Milbemax” in dogs

The article presents the results of studying the bioequivalence of the reproduced drug “Pinpramil” in comparison with the reference drug “Milbemax”. The experiments were conducted on 12 dogs, which were divided into two equal groups of 6 animals each. Dogs of one of the groups were given a reproduced drug, and animals of the other group were given a reference drug. The studied drugs were injected into the body of dogs once, individually, orally at a dose of the active substance, which corresponded to 0.5 mg of milbemycin oxime and 5 mg of praziquantel per 1 kg of body weight. After administration of the drugs, blood samples were taken from animals 14 times within 96 hours for subsequent production of serum, in which the content of praziquantel (including its active metabolite, trans-4-hydroxypraziquantel) and milbemycin oxime were determined by high-performance liquid chromatography. The obtained concentrations of these substances served as the basis for calculating their pharmacokinetic parameters in the body of dogs. The statistical analysis showed that the two-way confidence intervals for the Cmax, AUC0-t, AUC0-∞ ratios were in the range of 80–125%, and the Cmax/AUC0-t ratios were 75–133%. Thus, the research results have demonstrated that the drugs “Pinpramil” and “Milbemax” are bioequivalent.

Bioequivalence Study and Bioanalytical Method Development of Remogliflozin etabonate tablets in wistar rat plasma using RP-HPLC Method

A new RP-HPLC method for the bioequivalence study of two RGE (Remogliflozin etabonate) formulations in wistar rat plasma has been developed using Rosuvastatin as internal standard and validated as per ICH guidelines. The plasma samples were extracted with methanol and chromatographic separation was achieved on phenomenex C18 (250 x 4.6mm, 5μ) analytical column with a mobile phase of methanol: 0.2% TEA (pH adjusted to 3 with orthophosphoric acid) in the ratio of 78:22% v/v and detection at 227nm. Calibration curve was linear in the range of 100-600ng/ml and the r2 value was found to be 0.9906. The extraction efficiency of RGE from rat plasma at the concentration of 50, 100 and 150% was found to be 99.6%, 99.9% and 98.05%. The Intra-day precision and interday precision was found to be 0.14 - 0.777% and 0.0070% - 0.0572% respectively. The maximum concentration (Cmax) obtained for two brands ( selected brand 1 &amp; 2) formulation are 57.04 and 51.99 ng/ml respectively. The half life (t1/2) of two brands are calculated as 1 h. Area under the curve AUC 0- t of brand 1 and brand 2 is calculated as 343.235 and 310.1775ng h/ml and AUC 0-∞ is calculated to be 465.3665 and 501.4235ng h/ml respectively. The present study shows no significant difference in pharmacokinetic parameters between two products so the two formulations are considered to be bioequivalent.

Development and Validation of an HPLC-MS/MS Method for Quantification of Apixaban in Human Plasma

Introduction. Apixaban is an anticoagulant used in a number of thromboembolic diseases with an improved benefit-to-risk ratio, according to multiple clinical studies. Due to the prescription of apixaban as antithrombotic therapy in patients with COVID-19, an increase in its use has been observed. Thus, due to the widespread use of apixaban and the need to conduct pharmacokinetic and bioequivalence studies of the drug, it is important to develop and validate a simple and sensitive method for the quantitative determination of apixaban in human blood plasma.Aim. The aim of the study is to develop and validate a method for the determination of apixaban in human blood plasma using high-performance liquid chromatography with tandem mass selective detection (HPLC-MS/MS) for the subsequent bioanalytical study.Materials and methods. The determination of apixaban in human plasma was carried out by HPLC-MS/MS with rivaroxaban as an internal standard. The method of protein precipitation with acetonitrile was used as sample preparation. Mobile phase: 0.1 % solution of formic acid in water (eluent A); 0.1 % solution of formic acid in acetonitrile (eluent B). The total run time was 3.00 min. Column: Shim-pack Velox Biphenyl; 2.7 µm; 50 × 2.1 mm. Ionization source: electrospray with positive ionization mode. MRM transitions: 460.15 → 443.10 m/z (apixaban); 436.05 → 144.95 m/z (rivaroxaban).Results and discussion. The developed method was validated in accordance with the EAEU requirements for the following parameters: selectivity, calibration curve, accuracy and precision, lower limit of quantitation, suitability of standard samples, matrix effect, recovery, stability, carry-over, dilution effects. The parameters met the acceptance criteria.Conclusion. The confirmed analytical range of the developed and validated method was 1.00–300.00 ng/mL in blood plasma. The method for determining apixaban in blood plasma is simple and sensitive. This method was tested during the analytical part of the bioanalytical study and can be used to conduct other pharmacokinetic studies of apixaban drugs.

Volunteers in bioequivalence clinical trials: premises for participation. Part 1

Clinical trials, as an integral stage of the creation of any drug, require volunteers who are ready to go through the testing stage. Clearly, participation in a trial of any drug carries certain health risks, which makes it difficult to recruit volunteers. Development companies use various methods to stimulate potential participants, including regular monitoring of health status, creation of comfortable living conditions, free treatment, financial compensation for risks, etc. Particularly relevant for manufacturing companies is the recruitment of volunteers in case of conducting a bioequivalence phase study, when an already known drug, planned for release under a different brand (name), is being tested. The article presents the results of interviews with volunteers in order to study their motivation to participate in clinical trials of the bioequivalence phase, their experience of such participation, as well as opinions regarding the organization of clinical trials in the Russian Federation. The results of the study demonstrate a high level of interest among the volunteers to regularly participate in bioequivalence studies due to their relative safety for health, as well as financial interest and comfortable organization of the trial process. The socio-demographic profile of the “bioequivalence phase volunteer” is described, and the tendency towards the formation of a community of volunteers with experience of repeated participation in clinical trials for financial reward is identified.