Abstract Introduction: The immediate-release solid oral products containing very soluble and permeable drugs are candidates for the biowaiver process. This work aims to compare in vitro, in silico, and in vivo data to establish if previously published prednisone oral tablet formulations are biowaiver candidates. Method: To achieve this goal, permeation studies were conducted on Caco-2 cells. A previous bioequivalence study between the test and the reference drug product was applied on an in silico evaluation using Gastroplus® to assess the bioequivalence of two other previously proposed formulations. Results: The apparent permeability coefficient for prednisone presented a value of 3.69 x 10-5 cm/s in 180 minutes. The bioequivalence study shows that the tested and reference product was equivalent. The in silico simulations successfully predicted the pharmacokinetics of the tested and the other two formulations since they were validated with the in vivo study. Both exhibit the same plasma concentration vs. time profiles. Conclusions: Through the in silico results, it is possible to infer that the other two formulations tested may be bioequivalent concerning the reference product. This result may be helpful in biowaiver requesting. Toward to reduce costs and the use of human beings in bioequivalence studies, this approach could be an essential way to work in the pharmaceutical industry.

Resumen Introducción: Los productos orales sólidos de liberación inmediata que contienen fármacos muy solubles y permeables son candidatos para el proceso de bioexención. Este trabajo tiene como objetivo comparar datos in vitro, in silico e in vivo para establecer si las formulaciones de comprimidos orales de prednisona publicadas anteriormente son candidatas a la bioexención. Método: Para lograr este objetivo se realizaron estudios de permeación en células Caco-2. Se aplicó un estudio de bioequivalencia previo entre la formulación de prueba y el medicamento de referencia en una evaluación in silico utilizando Gastroplus® para evaluar la bioequivalencia de otras dos formulaciones propuestas anteriormente. Resultados: El coeficiente de permeabilidad aparente para prednisona presentó un valor de 3,69 x 10-5 cm/s en 180 minutos. El estudio de bioequivalencia muestra que el producto probado y de referencia era equivalente. Las simulaciones in silico predijeron con éxito la farmacocinética de las formulaciones probadas y las otras dos, ya que fueron validadas con el estudio in vivo . Ambos exhiben los mismos perfiles de concentración plasmática frente a tiempo. Conclusiones: A través de los resultados in silico , es posible inferir que las otras dos formulaciones ensayadas pueden ser bioequivalentes respecto al producto de referencia. Este resultado puede ser útil en la solicitud de bioexenciones. Para reducir los costos y el uso de seres humanos en los estudios de bioequivalencia, este enfoque podría ser una forma esencial de trabajar en la industria farmacéutica.

Resumen Introducción: Los estudios de Bioequivalencia demuestran la equivalencia en la calidad biofarmacéutica entre el producto farmacéutico multifuente y el medicamento de referencia, permitiendo el establecimiento de puentes entre las pruebas preclínicas y los ensayos clínicos asociados con el medicamento de referencia. La Metformina clorhidrato es el fármaco de primera elección para el tratamiento de la diabetes mellitus II y pertenece a la clase 3 del Sistema de Clasificación Biofarmacéutica. Objetivo: Establecer mediante pruebas de disolución in vitro, si 4 productos farmacéuticos multifuentes de liberación inmediata, de administración peroral, con Metformina clorhidrato, comercializados en Bolivia son bioequivalentes en relación con el producto de referencia, a través de un diseño experimental, con significancia estadística. Método: Se elaboraron perfiles de disolución de cada producto, tomando en cuenta las condiciones del método del ensayo de disolución establecido en la monografía “Metformina, tabletas” de la USP 39, considerando seis tiempos de muestreo. Se realizó el análisis cinético de los datos de porcentaje disuelto acumulado de los perfiles de disolución versus el tiempo. Se empleó el método de modelo independiente para comparar los perfiles de disolución de los productos a través del cálculo de los factores de diferencia (f1) y de similitud (f2) recomendados para estudios de bioexención por la Organización Mundial de la Salud. Resultados: Todos los productos tomados en cuenta en la investigación cumplieron satisfactoriamente los análisis de Control de Calidad. Los resultados del estudio de Bioequivalencia mostraron que existen diferencias estadísticamente significativas entre los productos del estudio. Conclusión: En este estudio no se demostró la Bioequivalencia in vitro de los productos B, C, D y E con relación al producto de referencia A, con base en pruebas de disolución in vitro

Abstract Introduction: Bioequivalence studies demonstrate the equivalence in biopharmaceutical quality between the multi-source pharmaceutical product and the reference medicine, allowing the establishment of bridges between preclinical tests and clinical trials associated with the reference medicine. Metformin hydrochloride is the drug of first choice for the diabetes mellitus II treatment and belongs to class 3 of the Biopharmaceutical Classification System. Objective: Establish by in vitro dissolution tests, whether 4 multisource pharmaceutical products of immediate release and peroral administration, with Metformin hydrochloride, marketed in Bolivia are bioequivalent in relation to the reference product, through an experimental design, with statistical significance. Method: Dissolution profiles were prepared for each product, taking into account the conditions of the dissolution test method established in the "Metformin, tablets" monograph of USP 39, considering six sampling times. The kinetic analysis of the accumulated dissolved percentage data of the dissolution profiles versus time was performed. The independent model method was used to compare the dissolution profiles of the products by calculating the difference factor (f1) and similarity factor (f2) recommended for Biowaiver studies, by the World Health Organization. Results: All the products taken into account in the investigation, satisfactorily fulfilled the Quality Control analysis. The results of the Bioequivalence study showed that there are statistically significant differences between the products of the study. Conclusion: In this study the in vitro bioequivalence of the products B, C, D and E in relation to the reference product A was not demonstrated, based on in vitro dissolution tests

Resumen Introducción. El diclofenaco sódico se clasifica como un antiinflamatorio no esteroide. Dado que es de venta libre, el paciente no tiene ningún seguimiento por parte de los equipos de salud, y como sus fuentes son múltiples, es necesario establecer la equivalencia entre ellas en estudios in vitro, que son los más prácticos y plantean un menor compromiso ético. Objetivos. Determinar la intercambiabilidad de diferentes marcas comerciales de diclofenaco sódico comparadas con el producto innovador mediante un estudio in vitro de tabletas comerciales de 50 mg, según los lineamientos del Sistema de Clasificación Biofarmacéutica (SCB). Materiales y métodos. Se desarrollaron pruebas físicas y químicas siguiendo las indicaciones de laedición 39 de la United States Pharmacopeia (USP). Para la cuantificación, se validó una metodología analítica según lo establecido en la mencionada farmacopea y la guía Q2 del International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use (ICH). Los perfiles de disolución y sus análisis se rigieron por lo establecido por la Organización Mundial de la Salud y las normas nacionales. Resultados. Todos los productos aprobaron las pruebas físicas. En cuanto a la disolución, la etapa ácida también fue superada por todas las marcas, pero una marca falló en la etapa alcalina. El análisis de similitud reveló que solo un producto fue equivalente al innovador y tres fueron supradisponibles, aunque dichas marcas también podrían considerarse equivalentes al producto innovador. Conclusiones. De las ocho marcas evaluadas, tres no cumplieron totalmente con la prueba de valoración del principio activo y del porcentaje de disolución; solo una marca fue intercambiable con el producto innovador y tres fueron supradisponibles comparadas con este, por lo cual no constituyen un riesgo para el paciente.

Abstract Introduction: Diclofenac sodium is classified as a non-steroidal anti-inflammatory drug. As diclofenac is an over-the-counter drug, its use among patients cannot be monitored by health teams in follow-up sessions. Given the multiple sources of diclofenac sodium, their interchangeability must be investigated, particularly in the form of in vitro studies, which are the most practical research type and entail minimal ethical commitment. Objectives: To determine the interchangeability of the different commercial brands of diclofenac sodium relative to the innovative product, this work carries out an in vitro study of eight commercial products of diclofenac sodium (50 mg) following the guidelines of the Biopharmaceutical Classification System. Materials and methods: Physical and chemical tests were developed following the guidelines of the 39th edition of the United States Pharmacopoeia. An analytical methodology was validated for the quantification of diclofenac according to the current pharmacopoeia and the Q2 guideline ofthe International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use (ICH). Dissolution profiles and their analyseswere governed by the regulations established by the World Health Organization and the national regulations. Results: All the products passed the physical tests. In the dissolution assays, the acid stage was overcome by all brands, but in the alkaline stage, one brand failed. The analysis of the similarities revealed that only one product was equivalent to the innovator and that three were supra-available, although these brands could also be considered equivalent to the innovator. Conclusions: Of the eight brands evaluated, three failed the test forthe active principle and the percentage of dissolution. Only one brand was found to be interchangeable with the innovator, and three were identified to besupra-availableand, thus, they do not present a risk for patients.

Resumo A partir da vigência da lei dos genéricos (1999), três tipos de produtos farmaceuticamente equivalentes são comercializados no Brasil: o medicamento inovador de refência (REF), o produto “similar” (S), e o genérico (G). O similar (nome de fantasia) e o genérico (nome genérico) tomam de empréstimo do REF (nome de fantasia) os dados clínicos de segurança e eficácia e a posologia. G (mas não S) é bioequivalente ao, e intercambiável com REF. Desde 2003, a Agência Nacional de Vigilância Sanitária (Anvisa) exige dados de testes de biodisponibilidade relativa para registrar (ou renovar o registro de) medicamentos S. Em 2014, a Anvisa estendeu o conceito de intercambialidade aos medicamentos similares com biodisponibilidade “comparável”, i.e., um medicamento similar “equivalente” (EQ). Medicamentos para doenças crônicas e “fármacos de dose crítica” estão listados entre os produtos EQ aprovados. A intercambialidade de medicamentos não-bioequivalentes suscita grande preocupação quanto a falhas terapêuticas e eventos adversos. Os receios são ainda maiores se os pacientes trocam um medicamento por outro durante o tratamento de doenças como epilepsia, insuficiência cardíaca, hipertensão, diabetes e/ou os produtos farmacêuticos substituídos tem um índice terapêutico estreito.

Abstract Since the enforcement of Generics Act (1999), three types of pharmaceutically equivalent products are marketed in Brazil: innovative reference (REF), “similar” (S) and generic (G) drugs. The S (brand name) and G (generic name) borrow from REF (brand name) clinical data on safety and efficacy and dosage regimen. G (but not S) is bioequivalent to and interchangeable with REF. Starting in 2003, Brazilian Sanitary Surveillance Agency (Anvisa) has required data on relative bioavailability tests (with REF) to approve (or renew registration of) S drugs. In 2014, Anvisa extended interchangeability notion to similar drugs with a “comparable” bioavailability, i.e., an “equivalent” similar drug (EQ). Drugs for chronic diseases and “critical dose medicines” are listed among the EQ drugs approved. Interchangeability of nonbioequivalent medicines raises deep concerns regarding therapeutic failures and adverse events. Concerns are even more worrisome if patients switch from one drug to another during an ongoing treatment for illnesses such as epilepsy, congestive heart failure, hypertension, diabetes and/or substitutable drugs have a narrow therapeutic index.

Resumo A partir da vigência da lei dos genéricos (1999), três tipos de produtos farmaceuticamente equivalentes são comercializados no Brasil: o medicamento inovador de refência (REF), o produto “similar” (S), e o genérico (G). O similar (nome de fantasia) e o genérico (nome genérico) tomam de empréstimo do REF (nome de fantasia) os dados clínicos de segurança e eficácia e a posologia. G (mas não S) é bioequivalente ao, e intercambiável com REF. Desde 2003, a Agência Nacional de Vigilância Sanitária (Anvisa) exige dados de testes de biodisponibilidade relativa para registrar (ou renovar o registro de) medicamentos S. Em 2014, a Anvisa estendeu o conceito de intercambialidade aos medicamentos similares com biodisponibilidade “comparável”, i.e., um medicamento similar “equivalente” (EQ). Medicamentos para doenças crônicas e “fármacos de dose crítica” estão listados entre os produtos EQ aprovados. A intercambialidade de medicamentos não-bioequivalentes suscita grande preocupação quanto a falhas terapêuticas e eventos adversos. Os receios são ainda maiores se os pacientes trocam um medicamento por outro durante o tratamento de doenças como epilepsia, insuficiência cardíaca, hipertensão, diabetes e/ou os produtos farmacêuticos substituídos tem um índice terapêutico estreito.

Abstract Since the enforcement of Generics Act (1999), three types of pharmaceutically equivalent products are marketed in Brazil: innovative reference (REF), “similar” (S) and generic (G) drugs. The S (brand name) and G (generic name) borrow from REF (brand name) clinical data on safety and efficacy and dosage regimen. G (but not S) is bioequivalent to and interchangeable with REF. Starting in 2003, Brazilian Sanitary Surveillance Agency (Anvisa) has required data on relative bioavailability tests (with REF) to approve (or renew registration of) S drugs. In 2014, Anvisa extended interchangeability notion to similar drugs with a “comparable” bioavailability, i.e., an “equivalent” similar drug (EQ). Drugs for chronic diseases and “critical dose medicines” are listed among the EQ drugs approved. Interchangeability of nonbioequivalent medicines raises deep concerns regarding therapeutic failures and adverse events. Concerns are even more worrisome if patients switch from one drug to another during an ongoing treatment for illnesses such as epilepsy, congestive heart failure, hypertension, diabetes and/or substitutable drugs have a narrow therapeutic index.

The global economic crisis and its impact on public finances in most developed countries are giving rise to cost-containment policies in healthcare systems. Prevailing legislation on medication requires the safety, quality, and efficacy of these products. A few countries include efficiency criteria, primarily for new medication that they wish to include in public financing. The appropriate use of generic and "biosimilar medication" is very important for maintaining the financial equilibrium of the Health Services. The problem in Latin America is that not all multisource products are bioequivalent and not all countries have the resources to conduct bioequivalence studies in vivo. The European Medicines Agency in 2005 adopted guidelines on "biosimilar medicines" and thirteen of them were subsequently approved for general release. Benchmarking of this model by other countries would be important. The influence of the pharmaceutical industry on political and administrative areas is enormous and control is necessary. The pharmaceutical companies claim that they act with corporate social responsibility, therefore, they must ensure this responsibility toward society.

La crisis económica y su impacto en las finanzas públicas en la mayoría de los países desarrollados, están originando políticas de contención del gasto en los servicios de salud. Las leyes actuales del medicamento exigen calidad, seguridad y eficacia de estos productos. Algunos países incluyen criterios de eficiencia para los nuevos medicamentos que desean ser incluidos en la financiación pública. El consumo apropiado de genéricos y "medicamentos biosimilares" es muy importante para mantener el equilibrio financiero de los servicios de salud. El problema en América Latina es que no todos los productos multifuentes son bioequivalentes y no todos los países tienen los recursos necesarios para realizar los estudios de bioequivalencia in vivo. La Agencia Europea del Medicamento en 2005 aprobó la directriz sobre "medicamentos biosimilares" y después se han autorizado trece de ellos para su comercialización. El referenciamiento de este modelo por otros países seria importante. La influencia de la industria farmacéutica sobre las áreas políticas y administrativas es necesario controlarla. Las compañías farmacéuticas afirman que actúan con responsabilidad social corporativa, por ello, se debería garantizar el cumplimiento de la misma con la sociedad.

The global economic crisis and its impact on public finances in most developed countries are giving rise to cost-containment policies in healthcare systems. Prevailing legislation on medication requires the safety, quality, and efficacy of these products. A few countries include efficiency criteria, primarily for new medication that they wish to include in public financing. The appropriate use of generic and "biosimilar medication" is very important for maintaining the financial equilibrium of the Health Services. The problem in Latin America is that not all multisource products are bioequivalent and not all countries have the resources to conduct bioequivalence studies in vivo. The European Medicines Agency in 2005 adopted guidelines on "biosimilar medicines" and thirteen of them were subsequently approved for general release. Benchmarking of this model by other countries would be important. The influence of the pharmaceutical industry on political and administrative areas is enormous and control is necessary. The pharmaceutical companies claim that they act with corporate social responsibility, therefore, they must ensure this responsibility toward society.

La crisis económica y su impacto en las finanzas públicas en la mayoría de los países desarrollados, están originando políticas de contención del gasto en los servicios de salud. Las leyes actuales del medicamento exigen calidad, seguridad y eficacia de estos productos. Algunos países incluyen criterios de eficiencia para los nuevos medicamentos que desean ser incluidos en la financiación pública. El consumo apropiado de genéricos y "medicamentos biosimilares" es muy importante para mantener el equilibrio financiero de los servicios de salud. El problema en América Latina es que no todos los productos multifuentes son bioequivalentes y no todos los países tienen los recursos necesarios para realizar los estudios de bioequivalencia in vivo. La Agencia Europea del Medicamento en 2005 aprobó la directriz sobre "medicamentos biosimilares" y después se han autorizado trece de ellos para su comercialización. El referenciamiento de este modelo por otros países seria importante. La influencia de la industria farmacéutica sobre las áreas políticas y administrativas es necesario controlarla. Las compañías farmacéuticas afirman que actúan con responsabilidad social corporativa, por ello, se debería garantizar el cumplimiento de la misma con la sociedad.

Antecedentes Los pacientes sometidos a procedimientos de intervención coronaria percutánea, al igual que en pacientes con enfermedad coronaria, deben recibir en forma indefinida tratamiento con ácido acetilsalicílico (AAS) y Clopidogrel. El desarrollo de nuevos productos a base de Clopidogrel a menores costos ayudan a evitar la discontinuación prematura de la terapia antiplaquetaria; entre estos productos desarrollados tenemos la marca Cravid® de Laboratorios LETI S.A.V. y esta debe comparar su efectividad e inocuidad con el patrón internacional de Clopidogrel marca Plavix® de Laboratorios Sanofi Aventis. Métodos: Se realizó un estudio: prospectivo, comparativo, cruzado, aleatorizado, en voluntarios sanos. Cada grupo recibió 1 comprimido de Clopidogrel Leti, CLOP-L o Clopidogrel Sanofi, CLOP-S de 75 mg. en una sola dosis al día durante 7 días continuos. Después de un período de lavado de 7 días recibieron el segundo tratamiento. Se midió la agregación plaquetaria al inicio de cada período y a los 7 días de tratamiento mediante agregometría óptica, con un agregómetro Óptico Modelo 490-2D marca Cronolog, con sistema de autocalibración que trabajó con plasma rico en plaquetas. Lectura 0-100% de paso de luz. Resultados: En ambos grupos se produjo un descenso importante en la agregabilidad plaquetaria a los 7 días de tratamiento de más del 50 % independiente del reactivo de ADP (Helena y Cronolog) utilizado para agregar (P < 0.05). Conclusiones: La relación de las medias e IC del porcentaje de agregación obtenida con las dos diferentes marcas comerciales de ADP se encontraron entre el 80 y 125%, por lo cual se concluye que ambas marcas de Clopidrogrel son bioequivalentes y por lo tanto, son perfectamente intercambiables.

Background The undergoing percutaneous coronary intervention procedures, as in patients with coronary disease should receive treatment indefinitely with acetylsalicylic acid (ASA) and Clopidogrel. Developing new products based on lower costs clopidogrel to help prevent premature discontinuation of antiplatelet therapy, among these products we have developed the brand Cravid® of LETI S,A.V. Laboratories® and this should compare their effectiveness and safety with the international standard Clopidogrel brand Plavix® of Sanofi Aventis Laboratories. Methods: We conducted a study: a prospective, comparative, cross-randomized, in healthy volunteers. Each group received 1 tablet of Clopidogrel Leti, CLO-L or Clopidogrel Sanofi-LCLOP-S 75 mg. in a single dose daily for 7 days. Followed for 7 day-washout period before administration of second treatment. Platelet aggregation was measured at the beginning of each period and 7 days of treatment by agregometría optics. With a agregómetro Optical Model 490-2D. Results: In both groups there was a decrease in platelets add to the 7 days of treatment for more than 50% independent of the reagent ADP (Helena and cronolog) used to add (P <0.05). Conclusions: The mean and CI at 90%, obtained with two different trademarks of ADP were between 80 and 125%, which was concluded that both brands are bioequivalent and are therefore perfectly interchangeable.

Secnidazol é um agente antimicrobiano utilizado principalmente no tratamento da amebíase. Para este estudo de bioequivalência de secnidazol em voluntários saudáveis, foram incluídos vinte e oito voluntárias mulheres no estudo randomizado cruzado. Cada voluntária recebeu uma única dose oral de secnidazol do produto teste e referência para comparação, com um intervalo de wash-out de duas semanas. As concentrações plasmáticas de secnidazol foram determinados por CLAE, as amostras foram extraídas com terc-butil-metil-éter: dicloromethano (60:40, v/v). O secnidazol e seu padrão interno metronidazol foram separados em uma coluna (C18 ) com fase móvel água ultra-pura:acetonitrila (85:15, v/v) e monitorado em 310 nm. As razões entre as médias geométricas de Cmáx, ASC0-t e ASC0-∞, encontraram-se dentro do estabelecido pela ANVISA, demonstrando que as formulações são bioequivalentes quanto à taxa e extensão de absorção

Secnidazole is an antimicrobial agent used primarily in the treatment of amoebiasis. For this bioequivalence study of secnidazole, twenty-eight healthy female volunteers were enrolled in a randomized crossover study. Each volunteer was given a single oral dose of secnidazole test preparation and then the reference preparation, or vice versa, with a wash out interval of two weeks. The plasma concentrations of secnidazole were determined by HPLC, and the samples were extracted with tert-butyl-methyl-ether: dicloromethane (60:40, v/v). Secnidazole and its parent compound metronidazole were separated on a C18 column with water:acetonitrile (85:15, v/v) as the mobile phase, and monitored at 310 nm. The ratio of mean Cmax, AUC0-t and AUC0-∞ values for the test and reference products were within the predetermined range established by ANVISA, demonstrating that the two formulations are bioequivalent in rate and extent of absorption.

Foi realizado estudo para identificar perfil de preços e disponibilidade de medicamentos segundo tipo de provedor, nas cinco regiões do país, para uma lista de medicamentos utilizados no tratamento de doenças prevalentes na população. Utilizou-se a metodologia de avaliação de preços proposta pela Organização Mundial da Saúde (OMS) pela Ação Internacional para a Saúde (AIS), adaptada para o cenário brasileiro. A análise evidenciou que no setor público há mais medicamentos similares do que genéricos em todas as regiões. Para a maioria dos medicamentos (71,4%) a disponibilidade de genéricos foi menor que 10%. No setor privado, a média do número de diferentes de versões genéricas encontradas nos pontos de venda foi muito inferior ao número de versões existentes no mercado. A análise mostrou correlação positiva entre o número de genéricos comercializados, ou encontrados no ponto de venda, e variação de preços em relação ao preço máximo ao consumidor. Estima-se que medicamentos genéricos estejam competindo em preço entre si e com similares, mas não com medicamentos de referência.

A study to identify availability and prices of medicines, according to type of provider, was conducted in the five regions of Brazil. A list of medicines to treat prevalent diseases was investigated, using the medicines price methodology developed by the World Health Organization and Health Action International, adapted for Brazil. In the public sector, bioequivalent (vis-à-vis reference brand) generics are less available than multisource products. For most medicines (71.4%), the availability of bioequivalent generics was less than 10%. In the private sector, the average number of different bioequivalent generic versions in the outlets was far smaller than the number of versions on the market. There was a positive correlation between the number of generics on the market, or those found at outlets, and the price variation in bioequivalent generic products, in relation to the maximum consumer price. It is estimated that price competition is occurring among bioequivalent generic drugs and between them and multisource products for the same substance, but not with reference brands.

Foi realizado estudo para identificar perfil de preços e disponibilidade de medicamentos segundo tipo de provedor, nas cinco regiões do país, para uma lista de medicamentos utilizados no tratamento de doenças prevalentes na população. Utilizou-se a metodologia de avaliação de preços proposta pela Organização Mundial da Saúde (OMS) pela Ação Internacional para a Saúde (AIS), adaptada para o cenário brasileiro. A análise evidenciou que no setor público há mais medicamentos similares do que genéricos em todas as regiões. Para a maioria dos medicamentos (71,4%) a disponibilidade de genéricos foi menor que 10%. No setor privado, a média do número de diferentes de versões genéricas encontradas nos pontos de venda foi muito inferior ao número de versões existentes no mercado. A análise mostrou correlação positiva entre o número de genéricos comercializados, ou encontrados no ponto de venda, e variação de preços em relação ao preço máximo ao consumidor. Estima-se que medicamentos genéricos estejam competindo em preço entre si e com similares, mas não com medicamentos de referência.

A study to identify availability and prices of medicines, according to type of provider, was conducted in the five regions of Brazil. A list of medicines to treat prevalent diseases was investigated, using the medicines price methodology developed by the World Health Organization and Health Action International, adapted for Brazil. In the public sector, bioequivalent (vis-à-vis reference brand) generics are less available than multisource products. For most medicines (71.4%), the availability of bioequivalent generics was less than 10%. In the private sector, the average number of different bioequivalent generic versions in the outlets was far smaller than the number of versions on the market. There was a positive correlation between the number of generics on the market, or those found at outlets, and the price variation in bioequivalent generic products, in relation to the maximum consumer price. It is estimated that price competition is occurring among bioequivalent generic drugs and between them and multisource products for the same substance, but not with reference brands.

Introduction: the use of generic drugs is becoming increasingly widespread, a practice mainly aimed at controlling health expenditure. Because generic drugs are bioequivalent with the original make, these products are generally interchangeable. Nevertheless, drugs with a narrow therapeutic margin are exceptions to this rule. In the case of potent opioids, and specifically, of transdermal fentanyl, the interchangeability of the initial prescription by other physicians or by pharmacists is questionable, since substitution could result in a change in analgesia or in the development of adverse effects, compromising the safety of the drug in individual patients. Material and methods: we reviewed the reports received in our pain unit of patients previously controlled with a specific brand of fentanyl (Durogesic® in all patients) who were switched to another brand of transdermal fentanyl by a physician other than the physician initially prescribing the drug or in the pharmacy. Results: in a 2-month period, we received 20 reports of loss of analgesic effect or of the presence of adverse effects, which were absent under Durogensic® treatment, after switching this brand for a generic transdermal fentanyl product. Conclusion: irrespective of the policy of generic drug use and given the potency of fentanyl and the possible changes in plasma concentration when one brand is changed to another, we believe that, to maintain analgesic effect and avoid the development of adverse effects, any change should be authorized by the physician originally prescribing the drug or by the physician responsible for the patient's care.

Introducción: el uso de medicamentos genéricos es una práctica cada vez más frecuente, encaminada fundamentalmente al control del gasto sanitario. Los genéricos, al ser bioequivalentes con la marca original, en general son intercambiables. No obstante, hay excepciones con los medicamentos de margen terapéutico estrecho. En el caso de los opiáceos potentes, y concretamente del fentanilo transdérmico, se cuestiona la intercambiabilidad de la prescripción inicial por parte de otros médicos o farmacéuticos, ya que podría incidir en un cambio en la analgesia o en la aparición de efectos secundarios y modificar la seguridad del fármaco para un determinado paciente. Material y métodos: se han revisado las comunicaciones recibidas en nuestra unidad del dolor de pacientes previamente controlados con una marca específica de fentanilo (en todos los casos Durogesic®) que fueron cambiados a otra presentación de fentanilo transdérmico por un médico distinto al prescriptor inicial o en la propia oficina de farmacia. Resultados: en un período de 2 meses se recibieron 20 comunicaciones de pérdida o disminución de la analgesia o de la presencia de efectos secundarios, previamente inexistentes bajo el tratamiento con Durogesic®, tras el cambio por una especialidad genérica de fentanilo transdérmico Conclusión: sin entrar a discutir la política del uso de genéricos, consideramos que dada la potencia de fentanilo y los posibles cambios en la concentración plasmática al intercambiar una presentación por otra, la intercambiabilidad sólo debería realizarse bajo el control del médico que inició el tratamiento o por el médico responsable del paciente, al objeto de mantener la analgesia conseguida y evitar la aparición de efectos adversos.

Foi desenvolvido e validado um novo método, sensível, exato e preciso por Cromatografia a Líquido de Alta Eficiência com detecção em UV para a determinação do sulfato de indinavir (IND) em plasma humano. O fármaco foi extraído do plasma através de extração líquido-líquido obtendo recuperação média de 73.9%, com limite inferior de quantificação de 0.05 µg/mL. O método foi aplicado em estudo de farmacocinética para verificar a bioequivalência entre um novo medicamento genérico e seu produto de referência. A bioequivalência entre os produtos foi determinada calculando-se um intervalo de confiança (IC) de 90% para a razão das médias do produto teste e referência compreendidas entre o intervalo de 0.80-1.25 proposto pela ANVISA e O FDA. Os produtos estudados são bioequivalentes e, portanto, intercambiáveis.

We report the development and validation of a new sensitive, accurate and precise HPLC method with ultraviolet detection for the determination of indinavir sulfate (IND) in human plasma and its application to a bioequivalence study of a new generic formulation. The extraction of IND from plasma samples was achieved by using liquid-liquid extraction with a mean recovery of 73.9%. The lower limit of quantification was 0.05 µg/mL. Bioequivalence between the products was determined by calculating 90% confidence intervals (CI) for the ratio of Cmax, AUC0-t and AUC0-inf values for the test and reference products, within the 0.80-1.25 interval proposed by ANVISA and FDA. Therefore the medications are bioequivalent and inter-exchangeable.

Objective: The present study describes the determination of the bioequivalence of the Cuban generic and trade formulations of stavudine, lamivudine, zidovudine, and indinavir. Design: The bioequivalence of each antiretroviral drug (test and reference formulations) was determined in 13 or 14subjects by means of a randomizedcrossover blind study with a wash-outperiod of ten days. Methods: The plasma concentrations were monitored over a period of 12 h after drug administration using a validated HPLC method. The pharmacokinetic parameters were determined by using WinNolin Professional software, Version 2.1. The comparison of the pharmacokinetic parameters was made at 95 % confidence interval using the NCSS 2000 and PASS 2000 trial software (paired t-test, null hypothesis).The bioequivalence study was conducted by the EqivTest software of statistical solutions. ANOVA was utilized with 90 % confidence interval. Results: The present study showed that no significant differences were observed in the means of AUC0-12, AUC0-¥, C max, and T max of both formulations of stavudine, lamivudine zidovudine, and indinavir. It wasconcluded that the studied pharmacokinetic parameters are withinthe established range. The ranges for Cmax, AUC0-12, and AUC0-¥ were 80-125 %, whereasthe range for Cmax of zidovudine was 70-143 %. Conclusion: These results prove that the Cuban generic antiretroviralsare bioequivalent to their respective innovatory products in terms ofthe rate and extent of absorption

Objetivo: El presente estudio describe los estudios de bioequivalencia de los genéricos cubanos antirretrovirales estavudina, lamivudina, zidovudina e indinavir con respecto a sus productos innovadores. Diseño: Los estudios de bioequivalencia de cada antirretroviral estudiado (formulación de prueba, P y referencia, R), se realizaron en 13 ó 14 sujetos, según el caso con la utilización de las medias en un estudio aleatorio, cruzado y a dosis única con un período de lavado de 10 días. Métodos: Las concentración de los antirretrovirales en plasma se monitorearon durante un período de 12 h después de la administración de estos, mediante el uso de métodos validados de cromatografía líquida de alta resolución (HPLC). Los parámetros farmacocinéticos se determinaron con el uso el software profesional WinNolin, versión 2.1. La comparación de los parámetros farmacocinéticos se realizó con un intervalo de confianza del 95 % con la utilización del software NCSS 2000 PASS 2000 (hipótesis nula). Para el estudio de bioequivalencia se usó el software Equiv Test de soluciones estadísticas, empleando ANOVA con el 90 % de intervalo de confianza. Resultados: El presente estudio mostró que no se observaron diferencias significativas en las medias de AUC0-12, AUC0-¥, Cmax y Tmax de ambas formulaciones de estavudina, lamivudina, zidovudina e indinavir. Se concluye que los parámetros farmacocinéticos estudiados se encuentran dentro de los rangos establecidos siendo 80-125 % para Cmax, AUC0-12, y AUC0-¥. En el caso de Cmax de la zidovudina el rango fue 70-143 %. Conclusión: Estos resultados avalan que los genéricos antirretrovirales cubanos son bioequivalentes con sus respectivos productos innovadores en términos de velocidad y magnitud de la absorción

Introducción: Los estudios de bioequivalencia o equivalencia comparada se realizan para demostrar que el producto en estudio, conocido como producto genérico, tiene la misma biodisponibilidad del producto de referencia, también conocido como producto innovador o de marca. Si los dos productos son bioequivalentes, se espera que tengan las mismas características de seguridad y eficacia. La bioequivalencia es establecida por la estimación estadística de diferencias significativas o no en los parámetros farmacocinéticos de área bajo la curva (ABC) y concentración máxima (Cmáx). En este caso, se evaluará y se comparará la biodisponibilidad de valsartán, un agente antihipertensivo inhibidor específico del receptor de angiotensina II subtipo AT1, en las membranas celulares del músculo liso vascular. Objetivo: Evaluar la bioequivalencia de dos productos farmacéuticos cuyo principio activo es valsartán, con base en la comparación de las medidas farmacocinéticas de cantidad y velocidad (en términos de tiempo requerido), con que el valsartán alcanza la circulación sanguínea después de ser administrado por vía oral a 15 voluntarios. Metodología: Se realizó un estudio aleatorizado, cruzado, a doble ciego, de dosis única en 15 voluntarios sanos con edades entre 19 y 28 años. El estudio se realizó en dos períodos; en cada período de tratamiento se administró una dosis de 320 mg de valsartán, con un período de lavado de 8 días entre el primero y segundo tratamiento. Las concentraciones plasmáticas se evaluaron por HPLC/UV con el método de adición de estándar, empleando losartán como estándar interno. Resultados: Para las tabletas de valsartán se obtuvieron los siguientes parámetros farmacocinéticas: ABC de 44,893 µg/mlxh, Cmáx de 6,430.3 µg/ml y Tmáx de 2 h. Para las cápsulas de valsartán se obtuvieron los siguientes parámetros farmacocinéticas: ABC de 44,963 µg/mlxh, Cmáx de 5,831.4 µg/ml y Tmáx de 2.5 h. Conclusión: Los resultados del estudio no mostraron diferencias significativas en los niveles de concentraciones plasmáticas después de la administración de las dos formulaciones de valsartán: 80 mg tabletas y 80 mg cápsulas. Por tanto, el diseño del estudio y la aplicación de los protocolos escogidos permitieron demostrar la bioequivalencia entre los productos.

Introduction: Bioequivalence or compared equivalence studies are used to demonstrate claims that the new product, named generic product, will have the same bioavailability as the reference product, named brand product. If two products are bioequivalent it means that they would expect to have the same efficacy and security. Bioequivalence is established by the statistical estimation of significant differences or not in the pharmacokinetics parameters of area under the curve (AUC) and maximum concentration (Cmax). In this case, bioequivalence will be evaluated and the bioavailability of valsartan will be compared. Valsartan is an agent antihypertensive and specific angiotensin II antagonist acting on the AT1 receptor subtype. Objective: The aim of this study was to evaluate the bioequivalence of two pharmaceutical products whose active principle is Valsartan, based on the comparison of the pharmacokinetic measures of rate and extent (in terms of required time) in which valsartan reaches the sanguineous circulation after a oral dose to 15 volunteers. Metodology: This was a randomized crossover double blind single-dose study on 15 male healthy volunteers aged between 19 and 28 years. The study was performed in two periods. Each treatment period consisted of a single-dose of 320 mg valsartan, with a wash-out time of 8 days between the first and second period. Plasma concentrations of valsartan were evaluated by HPLC/UV with method of addition of valsartan standard and losartan as internal standard. Results: Valsartan tablets formulation showed this pharmacokinetic parameters: AUC 44,893 µg/mlxh, Cmax 6,430.3 µg/ml and Tmax 2 h. Valsartan capsules formulation showed this pharmacokinetic parameters: AUC 44,963 µg/mlxh, Cmax 5,831.4 µg/ml and Tmax 2.5 h. Conclusion: The study showed no statistically significant differences in the plasma concentration levels after administration of the two formulations of valsartan: 80 mg tablets and 80 mg capsules. So, the design of the study and the application of the protocols chosen enabled the demonstration of bioequivalence between the products.