In-silico evaluation of Malawi essential medicines and reactive metabolites for potential drug-induced toxicities.

BACKGROUND: Drug-induced toxicity is one of the problems that have negatively impacted on the well-being of populations throughout the world, including Malawi. It results in unnecessary hospitalizations, retarding the development of the country. This study assessed the Malawi Essential Medicines List (MEML) for structural alerts and reactive metabolites with the potential for drug-induced toxicities. METHODS: This in-silico screening study used StopTox, ToxAlerts and LD-50 values toxicity models to assess the MEML drugs. A total of 296 drugs qualified for the analysis (those that had defined chemical structures) and were screened in each software programme. Each model had its own toxicity endpoints and the models were compared for consensus of their results. RESULTS: In the StopTox model, 86% of the drugs had potential to cause at least one toxicity including 55% that had the potential of causing eye irritation and corrosion. In ToxAlerts, 90% of the drugs had the potential of causing at least one toxicity and 72% were found to be potentially reactive, unstable and toxic. In LD-50, 70% of the drugs were potentially toxic. Model consensus evaluation results showed that the highest consensus was observed between ToxAlerts and StopTox (80%). The overall consensus amongst the three models was 57% and statistically significant (p < 0.05). CONCLUSIONS: A large number of drugs had the potential to cause various systemic toxicities. But the results need to be interpreted cautiously since the clinical translation of QSAR-based predictions depends on many factors. In addition, inconsistencies have been reported between screening results amongst different models.

The Discriminatory Power of the BCS-Based Biowaiver: A Retrospective With Focus on Essential Medicines.

This article summarizes historic developments, recent expert opinions, and (currently) unresolved challenges concerning the Biopharmaceutics Classification System (BCS)-based Biowaiver. An overview of approval statistics and application potential, case examples addressing the discriminatory power of the procedure, as well as an outlook on possible refinements in the future are provided and critically discussed. Over the last decade, regulatory guidance documents have been harmonized, for example, following scientific consent on allowing biowaivers for BCS class III drugs, making over 50% of orally administered drugs on the World Health Organization Essential Medicines List eligible for an abbreviated approval. Biowaiver monographs that present a complete risk-benefit evaluation for individual drugs have been issued by the International Pharmaceutical Federation for more than 25% of those drugs with the long-range aim of covering all essential drugs. Unresolved issues that have emerged from reported examples of false-negative and false-positive outcomes in the literature demand further adjustments to the regulatory requirements. Possible solutions for resolving these issues are the use of modeling and simulation and refined biorelevant in vitro tests that are better able to discriminate between dosage forms with unequal performance in vivo, potentially allowing biowaivers for selected BCS II drugs.

Biopharmaceutical optimization in neglected diseases for paediatric patients by applying the provisional paediatric biopharmaceutical classification system.

AIMS: Unavailability and lack of appropriate, effective and safe formulations are common problems in paediatric therapeutics. Key factors such as swallowing abilities, organoleptic preferences and dosage requirements determine the need for optimization of formulations. The provisional Biopharmaceutics Classification System (BCS) can be used in paediatric formulation design as a risk analysis and optimization tool. The objective of this study was to classify six neglected tropical disease drugs following a provisional paediatric BCS (pBCS) classification adapted to three paediatric subpopulations (neonates, infants and children). METHODS: Albendazole, benznidazole, ivermectin, nifurtimox, praziquantel and proguanil were selected from the 5th edition of the Model List of Essential Medicines for Children from the World Health Organization. Paediatric drug solubility classification was based on dose number calculation. Provisional permeability classification was based on log P comparison versus metoprolol log P value, assuming passive diffusion absorption mechanisms and no changes in passive membrane permeability between paediatric patients and adults. pBCS classes were estimated for each drug, according to different doses and volumes adapted for each age stage and were compared to the adult classification. RESULTS: All six drugs were classified into provisional pBCS in the three paediatric subpopulations. Three drugs maintained the same classification as for adults, ivermectin and benznidazole changed solubility class from low to high in neonates and proguanil changed from low to high solubility in all age stages. CONCLUSION: Provisional pBCS classification of these six drugs shows potential changes in the limiting factors in oral absorption in paediatrics, depending on age stage, compared to the adult population. This valuable information will aid the optimization of paediatric dosing and formulations and can identify bioinequivalence risks when comparing different formulations and paediatric populations.

Statistics on BCS classification of generic drug products approved between 2000 and 2011 in the USA.

The Biopharmaceutics Classification system (BCS) classifies drug substances based on aqueous solubility and intestinal permeability. The objective of this study was to use the World Health Organization Model List of Essential Medicines to determine the distribution of BCS Class 1, 2, 3, and 4 drugs in Abbreviated New drug Applications (ANDA) submissions. To categorize solubility and intestinal permeability properties of generic drugs under development, we used a list of 61 drugs which were classified as BCS 1, 2, 3, and 4 drugs with certainty in the World Health Organization Model List of Essential Medicines. Applying this list to evaluation of 263 ANDA approvals of BCS drugs during the period of 2000 to 2011 indicated 110 approvals (41.8%) for Class 1 drugs (based on both biowaiver and in vivo bioequivalence studies), 55 (20.9%) approvals for Class 2 drugs, 98 (37.3%) approvals for Class 3 drugs, and no (0%) approvals for Class 4 drugs. The present data indicated a trend of more ANDA approvals of BCS Class 1 drugs than Class 3 or Class 2 drugs. Antiallergic drugs in Class 1, drugs for pain relief in Class 2 and antidiabetic drugs in Class 3 have received the largest number of approvals during this period.

Aquisição de medicamentos genéricos em município de médio porte / Procurement of generic medicines in a medium size municipality / Adquisición de medicamentos genéricos en municipio de medio porte

OBJETIVO: Analisar o impacto financeiro da aquisição de medicamentos com a exigência da apresentação de testes de biodisponibilidade e/ou bioequivalência para o componente da Assistência Farmacêutica Básica. MÉTODOS: Estudo retrospectivo, documental, em atas dos processos licitatórios para aquisição de medicamentos em município de médio porte de Santa Catarina. Foram analisadas licitações sem (2007) e com (2008) a exigência de testes de bioequivalência e/ou de biodisponibilidade. Avaliaram-se o número de recursos apresentados pelos fornecedores, o número de processos licitatórios anuais necessários para a aquisição de todos os medicamentos padronizados, o tempo para a finalização do processo licitatório, o número de itens fracassados, o custo unitário dos medicamentos e o valor total da aquisição. RESULTADOS: Foram observados 2,6 por cento de itens fracassados em 2007 e 56,9 por cento em 2008. Entre os medicamentos, 60,0 por cento tiveram acréscimo e 29,3,0 por cento decréscimo em 2008 em relação a 2007. Os custos totais de aquisição para 150 medicamentos, considerando valores unitários praticados e o consumo médio anual, foram de R$ 2.288.120,00 para 2007 e de R$ 4.270.425,00 para 2008. CONCLUSÕES: A exigência dos testes de bioequivalência e/ou de biodisponibilidade elevou em mais de 100 por cento os custos com o financiamento do Componente da Assistência Farmacêutica Básica, indicando necessidade de discussão de uma Política de Medicamento Genérico em consonância com a Política de Assistência Farmacêutica e com a Relação Nacional de Medicamentos Essenciais.

OBJECTIVE: To analyze the financial impact of medicine procurement with the required bioavailability and or bioequivalence tests for the basic pharmaceutical services component. METHODS: A retrospective study, based on document research of competitive bidding for medicine procurement in a medium size municipality of Santa Catarina state, Southern Brazil. Bids that occurred with (2007) and without (2008) the requirement of bioequivalence and/or bioavailability tests were analyzed. The number of resources presented by providers, the number of annual bidding processes necessary to acquire all the standard medicines, the time to finalize the bidding process, the number of failing items, the per unit cost of medicines and the total value of procurement were evaluated. RESULTS: In 2007 and 2008 respectively, 2.6 percent and 56.9 percent of items failed. Among medicine purchases, 60.0 percent were increased and 29.3 percent decreased from 2008 to 2007.The total procurement costs for 150 medicines, considering per unit costs and average annual consumption was R$ 2,288,120.00 (2007) and R$ 4,270,425.00 (2008). CONCLUSIONS: The requirement for bioequivalence and/or bioavailability tests increased costs by more than 100 percent for the basic pharmaceutical services component. There is a need to discuss Generic Medicine Policies to agree with Pharmaceutical Assistance Policies and the National Essential Medicines Report.

OBJETIVO: Analizar el impacto financiero de la adquisición de medicamentos con la exigencia de la presentación de pruebas de biodisponibilidad y o bioequivalencia para el componente de la Asistencia Farmacéutica Básica. MÉTODOS: Estudio retrospectivo, documental, en actas de los procesos licitatorios para adquisición de medicamentos en municipio de medio porte de Santa Catarina, Sur de Brasil. Se analizaron licitaciones sin (2007) y con la exigencia de pruebas de bioequivalencia y/o biodisponibilidad (2008). Se evaluaron el número de recursos presentados por los proveedores, el número de procesos licitatorios anuales necesarios para la adquisición de todos los medicamentos estandarizados, el tiempo para la finalización del proceso licitatorio, el número de ítems fracasados, el costo unitario de los medicamentos y el valor total de la adquisición. RESULTADOS: Se observaron 2,6 por ciento de ítems fracasados en 2007 y 56,9 por ciento en 2008. Entre los medicamentos, 60,0 por ciento tuvieron incremento y 29,3 por ciento, disminución en 2008 con relación a 2007. Los costos totales de adquisición para 150 medicamentos, considerando valores unitarios practicados y el consumo promedio anual, fueron de R$ 2.288.120,00 para 2007 y de R$ 4.270.425,00 para 2008. CONCLUSIONES: La exigencia de las pruebas de bioequivalencia y/o biodisponibilidad elevó en más de 100 por ciento los costos con el financiamiento de la Asistencia Farmacéutica Básica, indicando necesidad de discusión de una Política de Medicamento Genérico en consonancia con la Política de Asistencia Farmacéutica y con la Relación Nacional de Medicamentos Esenciales.

Procurement of generic medicines in a medium size municipality.

OBJECTIVE: To analyze the financial impact of medicine procurement with the required bioavailability and or bioequivalence tests for the basic pharmaceutical services component. METHODS: A retrospective study, based on document research of competitive bidding for medicine procurement in a medium size municipality of Santa Catarina state, Southern Brazil. Bids that occurred with (2007) and without (2008) the requirement of bioequivalence and/or bioavailability tests were analyzed. The number of resources presented by providers, the number of annual bidding processes necessary to acquire all the standard medicines, the time to finalize the bidding process, the number of failing items, the per unit cost of medicines and the total value of procurement were evaluated. RESULTS: In 2007 and 2008 respectively, 2.6% and 56.9% of items failed. Among medicine purchases, 60.0% were increased and 29.3% decreased from 2008 to 2007.The total procurement costs for 150 medicines, considering per unit costs and average annual consumption was R$ 2,288,120.00 (2007) and R$ 4,270,425.00 (2008). CONCLUSIONS: The requirement for bioequivalence and/or bioavailability tests increased costs by more than 100% for the basic pharmaceutical services component. There is a need to discuss Generic Medicine Policies to agree with Pharmaceutical Assistance Policies and the National Essential Medicines Report.

Interacciones de medicamentos: mecanismos e importancia clínica / Interactions of medicaments: mechanisms and importance clinic

El presente estudio, es una revisión de los tipos de interacciones medicamentosas que existen. En él se describen los mecanismos de las interacciones y se dan ejemplos de importancia clínica. A grandes rasgos, las interacciones pueden clasificarse en beneficiosas y perjudiciales. Pero, más corrientemente, se subdividen, según su mecanismo, en interacciones farmacéuticas, farmacodinámicas y farmacocinéticas. De ninguna manera se pretende en este artículo hacer un estudio exhaustivo de las interacciones sino, más bien presentar una introducción a este tema.