INTRODUÇÃOEm um mundo cada vez mais globalizado e competitivo, a aparência física tornou-se um aspecto de grande importância na sociedade contemporânea. As manchas da pele, principalmente as faciais, não são estéticas e causam alguns transtornos que dificultam o bem-estar do indiví-duo no âmbito psicossocial.As hiperpigmentações são, em geral, distúrbios caracterizados pelo aumento de melanina e outros pigmentantes na pele. Os principais desencadeadores são as radiações solares, os hormônios sexuais e agentes externos, fontes de radicais livres. Neste contexto, tanto indústrias de cosméticos quanto farmacêuticas têm crescido a cada ano, diversificando suas matérias-primas e ampliando suas linhas de produtos disponíveis ao consumidor.Atualmente, a tecnologia farmacêutica tem dado
Sitagliptin is an inhibitor of the enzyme dipeptidyl peptidase-4, used for the treatment of type 2 diabetes mellitus. The crystal structure of active pharmaceutical solids determines their physical and chemical properties. The polymorphism, solvates and hydrates can influence the free energy, thermodynamic parameters, solubility, solid-state stability, processability and dissolution rate, besides directly affecting the bioavailability. Thus, the physicochemical characterization of an active pharmaceutical ingredient is required to guarantee the rational development of new dosage forms. In this context, we describe herein the solid-state characterization of three crystalline forms of sitagliptin: sitagliptin phosphate monohydrate, sitagliptin phosphate anhydrous and sitagliptin base form. The investigation was carried out using differential scanning calorimetry (DSC), thermogravimetry (TG)/derivative thermogravimetry (DTG), spectroscopic techniques, X-ray powder diffraction (XRPD) and morphological analysis by scanning electron microscopy. The thermal analysis revealed that during the dehydration of sitagliptin phosphate monohydrate (Tpeak = 134.43 °C, ΔH = −1.15 J g−1) there is a characteristic crystalline transition event, which alters the physicochemical parameters of the drug, such as the melting point and solubility. The crystalline behavior of sitagliptin base form differs from that of sitagliptin phosphate monohydrate and sitagliptin phosphate anhydrous, mainly with regard to the lower temperature of the fusion event. The melting point (Tpeak) values obtained were 120.29 °C for sitagliptin base form, 206.37 °C for sitagliptin phosphate monohydrate and 214.92 °C for sitagliptin phosphate anhydrous. In relation to the thermal stability, sitagliptin phosphate monohydrate and sitagliptin phosphate anhydrous showed a slight difference; however, both are more thermostable than the base molecule. Therefore, through this study it was possible to establish the most suitable crystalline form of sitagliptin for the development of a safe, effective and appropriate pharmaceutical dosage form.
In order for the pharmacological action of a topical dermal drug product to occur, the drug must first be released from the vehicle to be available to penetrate the skin layers and reach the site of action. Drug release is mainly dependent on the characteristics of the formulation. Currently, to register a generic or a similar drug product in Brazil performance testing of topical drug products for local action is not required. In this context, this aim of this study was to evaluate the in vitro release of commercial diclofenac diethylamine gel products available on the Brazilian pharmaceutical market, using the vertical diffusion cell method. Factors which may influence the test, such as the type of membrane used, and the effect of the formulation characteristics on the diffusion rate were evaluated. Brazilian legislation currently allows generic drug products to contain excipients other than the reference drug, which may affect the drug release from the vehicle. Only one of the four generic drug products tested could be considered equivalent to the reference Cataflam Emulgel ® . The cellulose acetate and polyethersulfone membranes tested were found to be interchangeable in the in vitro release studies carried out on this product. Uniterms:In vitro release test. Diclofenac diethylamine/gel. Synthetic membranes. Generic semisolid drug products.Para exercer ação farmacológica, medicamentos tópicos de aplicação cutânea precisam, primeiramente, liberar o fármaco do veículo, para que desta forma ele se torne disponível para penetração nas camadas da pele, até atingir seu local de ação. A liberação do fármaco do veículo depende principalmente das características da formulação. Até a presente data, para registrar um medicamento genérico ou similar no Brasil não se exigem testes de desempenho para produtos tópicos de ação local. O presente trabalho teve como objetivo avaliar a liberação in vitro de especialidades farmacêuticas de diclofenaco dietilamônio gel do mercado farmacêutico brasileiro, usando o sistema de célula de difusão vertical. Avaliaram-se fatores que influenciam o teste como o tipo de membrana usada nos ensaios de liberação e características da formulação que impactam a velocidade de difusão. A legislação vigente no País permite que medicamentos genéricos contenham excipientes diferentes do medicamento referência. Esta diferença afetou a liberação do fármaco do veículo. Dos quatro medicamentos genéricos testados apenas um seria considerado equivalente ao medicamento referência Cataflam Emulgel ® . As membranas de acetato de celulose e polietersulfona testadas apresentaram-se intercambiáveis nos estudos de liberação desse produto.
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