Capecitabine bioequivalence in healthy volunteers.

Capecitabine is a prodrug and is selectively activated by tumor cells to its cytotoxic moiety, 5-fluorouracil, by thymidine phosphorylase, which is generally expressed at high levels in tumors. Clinical and pharmacokinetic studies of capecitabine have been performed in patients with cancer. This study aims to evaluate the bioequivalence of two capecitabine formulations (150-mg tablet) using healthy male subjects under nonfasting conditions. The study was conducted as an open, randomized, three-period, semi-replicated design with three sequences (RRT, RTR, TRR) with a 1-week washout interval. The subjects were selected for the study after having their health status previously assessed by a clinical evaluation and laboratory tests (biochemical and hematological parameters, and urinalysis). A single capecitabine tablet (150 mg) was given in each occasion. Plasma capecitabine concentrations were analyzed by liquid chromatography coupled with tandem mass spectrometry (HPLC/MS/MS) with positive ion electrospray ionization using multiple reactions monitoring (MRM). The geometric mean and 90% confidence intervals (CI) of capecitabine/Xeloda® (T/R) percent ratio were 104.34% (98.74 - 110.25%) for AUClast, 103.06% (97.48 - 108.96%) for AUCinf, and 104.07% (88.13 - 122.90%) for Cmax. Since the 90% CI for Cmax, AUClast, and AUCinf ratios were all inside the 80 - 125% interval proposed by the US Food and Drug Administration Agency, it was concluded that the capecitabine formulation elaborated by Eurofarma Laboratórios Ltda. is bioequivalent to Xeloda® formulation for both the rate and the extent of absorption. The drug was well tolerated by the subjects, indicating that it is safe to perform capecitabine bioequivalence studies in healthy male subjects.
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Bioequivalence assay between orally disintegrating and conventional tablet formulations in healthy volunteers.

The purpose of this study was to evaluate bioequivalence of two commercial 8 mg tablet formulations of ondansetrona available in the Brazilian market. In this study, a simple, rapid, sensitive and selective liquid chromatography-tandem mass spectrometry method is described for the determination of ondansetron in human plasma samples. The method was validated over a concentration range of 2.5-60 ng/ml and used in a bioequivalence trial between orally disintegrating and conventional tablet ondansetron formulations, to assess its usefulness in this kind of study. Vonau flash (Biolab Sanus Farmacêutica, Brazil, as test formulations) and Zofran (GlaxoSmithKline, Brazil, as reference formulation) were evaluated following a single 8 mg dose to 23 healthy volunteers of both genders. The dose was administered after an overnight fast according to a two-way crossover design. Bioequivalence between the products was determinated by calculating 90% confidence interval (90% CI) for the ratio of C(max), AUC(0-t) and AUC(0-infinity) values for the test and reference products, using logarithmically transformed data. The 90% confidence interval for the ratio of C(max) (87.5-103.8%), AUC(0-t) (89.3-107.2%) and AUC(0-infinity) (89.7-106.0%) values for the test and reference products is within the 80-125% interval, proposed by FDA, EMEA and ANVISA. It was concluded that two ondansetron formulations are bioequivalent in their rate and extent of absorption.

Comparison between 200 mg generic celecoxib hard capsules and Celebra®: bioequivalence study in healthy male and female subjects under fasting conditions after a single dose / Comparação entre celecoxibe genérico de 200 mg em cápsulas duras e Celebra®: estudo de bioequivalência em indivíduos saudáveis do sexo masculino e feminino, em jejum, após uma dose única

ABSTRACT BACKGROUND AND OBJECTIVES: The objective of this study was to assess the bioequivalence between two 200 mg celecoxib hard capsule formulations administered to healthy male and female participants under fasting conditions with the aim of providing an alternative pharmaceutical product to the reference drug, Celebra®. METHODS: A randomized, open label, single dose, 2x2 crossover trial was conducted with 60 adult healthy subjects under fasting conditions comparing single doses of two celecoxib hard capsules formulation. Pharmacokinetic parameters were calculated following the determination of drugs concentrations in human plasma using a validated liquid chromatography with a tandem mass spectrometer detector method (LC-MS/MS). RESULTS: Statistical analysis provided geometric mean of test/reference ratio, confidence intervals, intra-subject variation coefficient and power of the test to the pharmacokinetic parameters Cmax, AUC0-t, and AUC0-∞. Confidence intervals for the geometric mean (90% CI) of the test/reference drugs for celecoxib were 98.26 to 122.75% for Cmax, 100.27% to 110.78% for AUC0-t, and 96.87% to 110.29% for AUC0-∞. The power of the test found was 95.09% for Cmax, 100.00% for AUC0-t, and 99.99% for AUC0-∞. CONCLUSION: The formulations met the Brazilian standards for interchangeability, as the confidence intervals for Cmax and AUC0-t ratios are within the range of 80% to 125%, thus meeting the requirements of the legislation during market registration. The researched product was approved by the regulatory authorities and became a commercially competitive option to the reference product for the Brazilian population.

RESUMO JUSTIFICATIVA E OBJETIVOS: O objetivo deste estudo foi avaliar a bioequivalência entre duas formulações de cápsulas duras de celecoxibe de 200 mg administradas a participantes saudáveis do sexo masculino e feminino em condições de jejum com o objetivo de fornecer um produto farmacêutico alternativo ao fármaco de referência, Celebra®. MÉTODOS: Estudo randomizado, aberto, de dose única e cruzado 2x2. Foi conduzido com 60 indivíduos adultos saudáveis em condições de jejum, comparando doses únicas de duas formulações de cápsulas duras de celecoxibe. Os parâmetros farmacocinéticos foram calculados após a determinação das concentrações dos fármacos no plasma humano usando uma cromatografia líquida validada com um método detector de espectrômetro de massa em tandem (LC-MS/MS). RESULTADOS: A análise estatística forneceu a média geométrica da razão teste/referência, os intervalos de confiança, o coeficiente de variação intra-sujeito e o poder do teste para os parâmetros farmacocinéticos Cmáx, AUC0-t e AUC0-∞. Os intervalos de confiança para a média geométrica (IC 90%) dos fármacos teste/referência para o celecoxibe foram 98,26 a 122,75% para Cmáx, 100,27% a 110,78% para AUC0-t e 96,87% a 110,29% para AUC0-∞. O poder do teste encontrado foi de 95,09% para Cmáx, 100,00% para AUC0-t e 99,99% para AUC0-∞. CONCLUSÃO: As formulações atenderam aos padrões brasileiros de intercambialidade, pois os intervalos de confiança para as razões Cmáx e AUC0-t estão dentro da faixa de 80% a 125%, atendendo, assim, às exigências da legislação para o registro no mercado. O produto pesquisado foi aprovado pelas autoridades regulatórias e tornou-se uma opção comercialmente competitiva ao produto de referência para a população brasileira.

Bioequivalence and pharmacokinetics of two zidovudine formulations in healthy Brazilian volunteers: an open-label, randomized, single-dose, two-way crossover study.

BACKGROUND: Zidovudine is a thymidine nucleoside reverse transcriptase inhibitor with activity against HIV type 1. Some (approximately 8) generic formulations of zidovudine are available in Brazil; however, based on a literature search, information concerning their bioavailability and pharmacokinetic properties in the Brazilian population has not been reported. OBJECTIVE: The aim of this study was to compare the bioavailability and pharmacokinetic properties of 2 capsule formulations of zidovudine 100 mg in healthy Brazilian volunteers. METHODS: This open-label, randomized, 2-way crossover study utilized a 1-week washout period between doses. Blood samples were collected for 8 hours after a single dose of zidovudine 100-mg test (Zidovudina, Fundação para o Remédio Popular, São Paulo, Brazil) or reference formulation (Retrovir, GlaxoSmithKline, Philadelphia, Pennsylvania). Plasma zidovudine concentrations were determined using a validated high-performance liquid chromatography method with ultraviolet detection at 265 nm. C(max), T(max), AUC(0-t), AUC(0-infinity), t(1/2), and the elimination constant (k(e)) were determined using noncompartmental analysis. The formulations were considered bioequivalent if the 90% CIs for C(max), AUC(0-t), and AUC(0-infinity) fell within the interval of 80% to 125%,the regulatory definition set by the US Food and Drug Administration (FDA). RESULTS: Twenty-four healthy volunteers (12 males, 12 females; mean age, 27 years; weight, 60 kg; height, 167 cm) were enrolled and completed the study. The 90% CIs of the treatment ratios for the logarithmic transformed values of C(max), AUC(max)0-t, and AUC(0-infinity) were 80.0% to 113.6%, 93.9% to 109.7%, and 93.6% to 110.1%, respectively. The values for the test and reference formulations were within the FDA bioequivalence definition intervals of 80% to 125%. CONCLUSIONS: In this small study in healthy subjects, no statistically significant differences in C(max), AUC(0-t), and AUC(0-infinity) were found between the test and reference formulations of zidovudine 100-mg capsules. The 90% CIs for the mean ratio values for the test and reference formulations of AUC(0-t), AUC(0-infinity), and C(max) indicated that the reported data were entirely within the bioequivalence acceptance range proposed by the FDA of 80% to 125% (using log-transformed data).

HPLC-UV determination of metformin in human plasma for application in pharmacokinetics and bioequivalence studies.

In this study, a simple, rapid and sensitive HPLC method with UV detection is described for determination of metformin in plasma samples from bioequivalence assays. Sample preparation was accomplished through protein precipitation with acetonitrile and chromatographic separation was performed on a reversed-phase phenyl column at 40 degrees C. Mobile phase consisted of a mixture of phosphate buffer and acetonitrile at flow rate of 1.0 ml/min. Wavelength was set at 236 nm. The method was applied to a bioequivalence study of two drug products containing metformin, and allowed determination of metformin at low concentrations with a higher throughput than previously described methods.

Bioequivalence of 2 formulations of montelukast (5 mg chewable tablet) in the fasting state: an open-label randomized, single-dose, 2-period, crossover study / Estudo de bioequivalência entre duas formulações de comprimidos mastigáveis de Montelucaste de 5 mg em condições de jejum: um estudo randomizado, de dose única, aberto, dois períodos, cruzado

Introduction: Montelukast, a selective and active leukotriene receptor antagonist, is one of the most common agents in asthma treatment for both adults and children. Objective: To assess whether the pharmacokinetic profiles of two formulations of montelukast were similar after a single 5 mg dose (chewable tablets), administered orally under fasting conditions, sampling blood before and 36 hours after administration. Methods: This was a randomized, 2-sequence, 2-period, crossover study of 2 chewable tablet formulations of the drug: Singulair®, provided by Merck Sharp and Dohme Farmacêutica Ltda. (reference), and generic montelukast, manufactured by Eurofarma Laboratórios S.A. (test). Plasma samples obtained from 35 participants were analyzed for montelukast through high-performance liquid chromatography coupled to tandem mass spectrometry, with montelukast-d6 as the internal standard. Peak montelukast concentrations were 299.313 (SD, 11.039) ng/mL for the reference formulation and 279.803 (SD, 10.085) ng/mL for test formulation. Results: Statistical analysis showed no significant differences between AUC0-36h, AUC0-inf, or Cmax between formulations, with the following test/reference ratios: 102.458 for AUC0-36h, 102.522 for AUC0-inf, and 93.490 for Cmax. No serious adverse events were reported during the trial. Our results demonstrated the bioequivalence of Singulair® and Eurofarma's generic montelukast. Conclusions: Our results revealed that the new generic tablets are clinically safe and can be used interchangeably with the brand name product. Eurofarma's montelukast offers a safe, effective, and cheaper treatment option for people with asthma or allergic rhinitis.

Introdução: O montelucaste, um antagonista seletivo e ativo dos receptores de leucotrienos, é um dos agentes mais comumente usados na prática clínica no tratamento da asma, tanto em adultos quanto em crianças. Objetivo: Avaliar se os perfis farmacocinéticos de duas formulações de montelucaste eram semelhantes após uma dose única de comprimidos mastigáveis de 5 mg, administrados por via oral em jejum, coletando amostras de sangue desde antes da administração até 36 horas depois disso. Métodos: Estudo comparativo randomizado, 2 sequências e 2 períodos, cruzado, de dois medicamentos em comprimidos mastigáveis: Singulair®, fornecido pela Merck Sharp e Dohme Farmacêutica Ltda. (referência) e Montelucaste 5 mg, fabricado pela Eurofarma Laboratórios S.A. (teste). Amostras de plasma obtidas de 35 indivíduos elegíveis foram analisadas para montelucaste por cromatografia líquida de alta eficiência acoplada a espectrometria de massa em tandem, tendo Montelucaste-d6 como padrão interno. As concentrações máximas de montelucaste foram 299,313±11,039 ng/mL para referência e 279,803±10,085 ng/mL para formulação de teste. Resultados: A análise estatística não mostrou diferenças significativas para AUC0-36h, AUC0-inf e nem para Cmax entre as formulações, apresentando as razões Teste/Referência: 102,458 para AUC0-36h, 102,522 para AUC0-inf e 93,490 para Cmax. Nenhum evento adverso grave foi relatado durante o estudo. De acordo com a regulamentação brasileira, o atual estudo farmacocinético demonstrou bioequivalência entre os agentes individuais e forneceu evidências de bioequivalência entre Singulair® e Montelukast fabricado pela Eurofarma. Resultado: Os resultados mostraram que os novos comprimidos genéricos são clinicamente seguros e podem ser trocados pela marca original. O montelucaste da Eurofarma oferece uma opção de tratamento mais barata, segura e eficaz para indivíduos com asma ou rinite alérgica.

Pharmacokinetics and bioequivalence evaluation of cyclobenzaprine tablets.

The purpose of this study was to investigate cyclobenzaprine pharmacokinetics and to evaluate bioequivalence between two different tablet formulations containing the drug. An open, randomized, crossover, single-dose, two-period, and two-sequence design was employed. Tablets were administered to 23 healthy subjects after an overnight fasting and blood samples were collected up to 240 hours after drug administration. Plasma cyclobenzaprine was quantified by means of an LC-MS/MS method. Pharmacokinetic parameters related to absorption, distribution, and elimination were calculated. Cyclobenzaprine plasma profiles for the reference and test products were similar, as well as absorption pharmacokinetic parameters AUC (reference: 199.4 ng ∗ h/mL; test: 201.6 ng ∗ h/mL), Cmax (reference: 7.0 ng/mL; test: 7.2 ng/mL), and T(max) (reference: 4.5 h; test: 4.6 h). Bioequivalence was evaluated by means of 90% confidence intervals for the ratio of AUC (93%-111%) and C(max) (93%-112%) values for test and reference products, which were within the 80%-125% interval proposed by FDA. Cyclobenzaprine pharmacokinetics can be described by a multicompartment open model with an average rapid elimination half-life (t(1/2)ß) of 3.1 hours and an average terminal elimination half-life (t(1/2)γ) of 31.9 hours.

Bioequivalence evaluation of single doses of two tramadol formulations: a randomized, open-label, two-period crossover study in healthy Brazilian volunteers.

BACKGROUND: Tramadol is a well tolerated and effective analgesic used to treat moderate to severe pain. Several generic formulations of tramadol are available in Brazil; however, published information regarding their bioequivalence in the Brazilian population is not available. A study was designed for Brazilian regulatory authorities to allow marketing of a generic formulation. OBJECTIVE: The purpose of this study was to compare the bioequivalence of 2 commercial tablet preparations containing tramadol 100 mg marketed for use in Brazil. METHODS: A randomized, open-label, 2 x 2 crossover study was performed in healthy Brazilian volunteers under fasting conditions with a washout period of 12 days. Two tablet formulations of tramadol 100 mg (test and reference formulations) were administered as a single oral dose, and blood samples were collected over 24 hours. Tramadol plasma concentrations were quantified using a validated HPLC method. A plasma concentration-time profile was generated for each volunteer and then mean values were determined, from which C(max), T(max), AUC(0-infinity) k(e), and t(1/2) were calculated using a noncompartmental model. Bioequivalence between the products was determined by calculating 90% CIs for the ratios of C(max) AUC(0-t) and AUC(0-infinity), values for the test and reference products using log-transformed data. Tolerability was assessed by monitoring vital signs (temperature, blood pressure, heart rate), laboratory tests (hematology, blood biochemistry, hepatic function, urinalysis), and interviews with the volunteers before medication administration and every 2 hours during the study. RESULTS: Twenty-six healthy volunteers (13 men, 13 women) were enrolled in and completed the study. Mean (SD) age was 30 (6.8) years (range, 21-44 years), mean weight was 64 (8.3) kg (range, 53-79 kg), and mean height was 166 (6.4) cm (range, 155-178 cm). The 90% CIs for the ratios of Cmax (1.01-1.17), AUC(0-t) (1.00-1.13), and AUC(0-infinity). (1.00-1.14) values for the test and reference products fell within the interval of 0.80 to 1.25 proposed by most regulatory agencies, including the Brazilian regulatory body. No clinically important adverse effects were reported; only mild somnolence was reported by 4 volunteers and mild headaches by 5 volunteers, and there was no need to use medication to treat these symptoms. CONCLUSION: Pharmacokinetic analysis in these healthy Brazilian volunteers suggested that the test and reference formulations of tramadol 100-mg tablets met the regulatory requirements to assume bioequivalence based on the Brazilian regulatory definition.

Average bioequivalence of single 500 mg doses of two oral formulations of levofloxacin: a randomized, open-label, two-period crossover study in healthy adult Brazilian volunteers

Average bioequivalence of two 500 mg levofloxacin formulations available in Brazil, Tavanic(c) (Sanofi-Aventis Farmacêutica Ltda, Brazil, reference product) and Levaquin(c) (Janssen-Cilag Farmacêutica Ltda, Brazil, test product) was evaluated by means of a randomized, open-label, 2-way crossover study performed in 26 healthy Brazilian volunteers under fasting conditions. A single dose of 500 mg levofloxacin tablets was orally administered, and blood samples were collected over a period of 48 hours. Levofloxacin plasmatic concentrations were determined using a validated HPLC method. Pharmacokinetic parameters Cmax, Tmax, Kel, T1/2el, AUC0-t and AUC0-inf were calculated using noncompartmental analysis. Bioequivalence was determined by calculating 90% confidence intervals (90% CI) for the ratio of Cmax, AUC0-t and AUC0-inf values for test and reference products, using logarithmic transformed data. Tolerability was assessed by monitoring vital signs and laboratory analysis results, by subject interviews and by spontaneous report of adverse events. 90% CIs for Cmax, AUC0-t and AUC0-inf were 92.1% - 108.2%, 90.7% - 98.0%, and 94.8% - 100.0%, respectively. Observed adverse events were nausea and headache. It was concluded that Tavanic(c) and Levaquin(c) are bioequivalent, since 90% CIs are within the 80% - 125% interval proposed by regulatory agencies.

A bioequivalência média de duas formulações de levofloxacino disponíveis no Brasil, Tavanic(c) (Sanofi-Aventis Farmacêutica Ltda, Brasil, produto referência) e Levaquin(c) (Janssen-Cilag Farmacêutica Ltda, Brasil, produto teste) foi determinada por meio da realização de ensaio aleatório, aberto, cruzado, com dois períodos e duas sequências, em 26 voluntários sadios em condições de jejum. Amostras de sangue dos voluntários foram obtidas ao longo de um período de 48 horas após administração de dose única de 500 mg de levofloxacino. As concentrações plasmáticas do fármaco foram determinadas por método cromatográfico validado. Os parâmetros farmacocinéticos Cmax, Tmax, Kel, T1/2el, AUC0-t e AUC0-inf foram calculados por análise não compartimental. A bioequivalência foi determinada pelo cálculo de intervalos de confiança 90% (IC 90%) para as razões entre os valores de Cmax, AUC0-t e AUC0-inf obtidos para os produtos teste e referência, usando dados transformados logaritmicamente. A tolerabilidade foi avaliada pelo acompanhamento dos sinais vitais e resultados de exames laboratoriais, por consultas e por relato espontâneo dos voluntários. ICs 90% para Cmax, AUC0-t e AUC0-inf foram 92.1% - 108.2%, 90.7% - 98.0%, e 94.8% - 100.0%, respectivamente. Os eventos adversos observados foram náusea e cefaleia. Concluiu-se que os produtos Tavanic(c) e Levaquin(c) são bioequivalentes, uma vez que os ICs 90% estão dentro da faixa de 80%-125% proposta pelas agências reguladoras.

Development and validation of a HPLC-MS-MS method for quantification of metronidazole in human plasma.

The objective of this study was to describe an analytical validation of a simple, rapid, sensitive, and selective liquid chromatography (LC)-tandem mass spectrometry (MS-MS) method for quantification of metronidazole in human plasma samples from bioavailability studies. The plasma samples were pre-treated by liquid-liquid extraction (LLE) with ethyl acetate. Metronidazole and the internal standard (IS) zidovudine were analyzed by combined reversed-phase LC-MS-MS with positive ion electrospray ionization. Multiple reactions monitoring (MRM) of the transitions were used as follows: m/z 171.97 > 127.97 for metronidazole and m/z 268.08 > 126.96 for IS. The main chromatography conditions used were a Varian C(18) Microssorb model (150 mm x 4.6 mm i.d., 5 microm particle size) column, and the mobile phase was composed of acetonitrile and 10 mM ammonium acetate (80:20, v/v) and 0.1% formic acid. Flow rate used was 1.0 mL/min with splitter. The method was linear over a concentration range of 0.05-8.00 microg/mL. Acceptable precision and accuracy were obtained for concentrations over the standard curve range. The developed method was validated and successfully applied to a pilot bioequivalence study of metronidazole in healthy volunteers.

Bioequivalence study of two oral formulations of cefadroxil in healthy volunteers.

Two different cefadroxil (CAS 50370-12-2) formulations were evaluated for their relative bioavailability in 24 healthy volunteers who received a single 500 mg oral dose of each preparation. An open, randomized clinical trial designed as a two-period crossover study with a 7-day washout period between doses was employed. Plasma samples for assessments of their cefadroxil concentration by HPLC-UV were obtained over 8 h after administration. Values of 48.94 +/- 10.18 pg x h/ml for test, and 48.51 +/- 9.02 microg x h/ml for the reference preparation AUC(0-t) demonstrate a nearly identical extend of drug absorption. Maximum plasma concentration Cmax of 16.04 +/- 4.94 microg/ml and 16.01 + 4.02 microg/ml achieved for the test and reference preparations did not differ significantly. The parametric 90% confidence intervals (CI) of the mean of the difference (test-reference) between log-transformed values of the two formulations were 96.80% to 104.51% and 92.01% to 107.00% for AUC(0-t) and Cmax, respectively. Since for both AUC(0-t) or Cmax the 90% CI values are within the interval proposed by the Food and Drug Administration, the test product is bioequivalent to the reference product for both the rate and extent of absorption after single dose administration.

Bioequivalence evaluation of two different tablet formulations of tinidazole in healthy volunteers.

The bioequivalence of two different tablet formulations of tinidazole (CAS 19387-91-8) was determined in healthy volunteers after a single dose in a randomized crossover study, with a 1-week washout period between the doses. Reference and test products were administered to 24 volunteers with 240 mL water after overnight fasting. Plasma concentrations of tinidazole were monitored by a high-performance liquid chromatographic method (HPLC) over a period of 72 h after the administration. The pharmacokinetic parameters AUC(o-t), AUCo-infinity, C(max), T(max), T((1/2)el) and beta were determined from plasma concentration time profile of both formulations and found to be in good agreement with previously reported values. The calculated pharmacokinetic parameters were compared statistically to evaluate bioequivalence between the two brands. The analysis of variance (ANOVA) did not show any significant difference between the two formulations and 90% confidence intervals for the ratio of C(max) (93.9 -102.6%), AUC(o-t) (94.9-101.1%) and AUC(o-infinity) (94.6-100.8%) values for the test and reference products were within the 80-125% interval, satisfying the bioequivalence criteria of the European Committee for Proprietary Medicinal Products and the US Food and Drug Administration Guidelines. These results Indicate that the test and the reference products of tinidazole are bioequivalent and, thus, may be prescribed interchangeably.

Emprego de meta-análise para avaliação da intercambialidade entre medicamentos / Use of meta-analysis in order to evaluate the interchangeable of medicines

No Brasil, os medicamentos genéricos e similares devem ser submetidos a ensaios de biodisponibilidade relativa/ bioequivalência para comprovação de sua intercambiabilidade com o medicamento referência. Nestes ensaios, o medicamento genérico, ou similar, é comparado com o medicamento referência em um estudo cruzado, mas não é comparado com outros genéricos ou similares do mercado. Desta forma, podemos afirmar que todo medicamento genérico ou similar é intercambiável com o medicamento de referência, mas não temos informações sobre a intercambiabilidade de um genérico com outro genérico ou com um similar. Entretanto, é comum que os pacientes substituam não apenas medicamento de referência pelo genérico ou similar correspondente, mas também um genérico por outro genérico, ou um genérico por um similar. Assim sendo, a questão que se coloca é se essas substituições entre genéricos e entre genérico e similar, podem gerar problemas de eficácia e/ou segurança para os pacientes. Para tentar responder essa questão foi proposta uma análise estatística, a meta-análise, onde seria possível avaliar a biodisponibilidade relativa/ bioequivalência entre genéricos, entre similares ou genérico e similar a partir dos resultados dos ensaios em que estes medicamentos foram comparados ao referência. Assim, o objetivo do estudo proposto foi aplicar técnicas estatísticas de meta-análise na avaliação da intercambiabilidade entre diferentes medicamentos similares de um mesmo medicamento referência. Amoxicilina foi escolhida como fármaco modelo para este estudo. Foram realizados três estudos de bioidisponibilidade relativa do tipo quantitativo direto, com delineamento aleatório, cruzado e aberto para comparar os produtos (Ti, T2, T3) a três diferentes lotes do produto de referência (R1, R2, R3)...