RESUMO
Levodopa, (S)-2-amino-3-(3,4-dihydroxyphenyl) propanoic acid, is still considered the gold standard treatment for Parkinson's disease. However, oral levodopa shows poor pharmacokinetics and its efficacy becomes problematic with the progression of the disease. Pulmonary delivery using the association of the polymers: chitosan, hyaluronic acid and HPMC, represents a novel approach to overcome this problem. A stability-indicating liquid chromatography method for the quantitative determination of levodopa microparticles for pulmonary delivery was developed as well as its photodegradation kinetics in solution. The developed and validated method was applied for the analyses of the novel formulation as well as for protocols of stability studies.
Assuntos
Antiparkinsonianos/administração & dosagem , Levodopa/administração & dosagem , Administração por Inalação , Antiparkinsonianos/química , Antiparkinsonianos/efeitos da radiação , Cromatografia Líquida de Alta Pressão , Estabilidade de Medicamentos , Excipientes , Cinética , Levodopa/química , Levodopa/efeitos da radiação , Luz , Limite de Detecção , Nanopartículas , Soluções Farmacêuticas , Fotoquímica , Padrões de Referência , Reprodutibilidade dos Testes , Espectrofotometria UltravioletaRESUMO
Entacapone is indicated for clinical use as an adjunct to levodopalcarbidopa to treat patients with idiopathic Parkinson's Disease who experience the signs and symptoms of end-of-dose wearing-off. The aim of this study was to determine the photodegradation kinetics and to elucidate the structure of the main degradation product. The stability of entacapone was studied in order to investigate the degradation kinetics of this drug using LC as a stability indicator. Entacapone was subjected to accelerated photodegradation. This study was carried out with methanolic solutions, prepared from coated tablets, in quartz cells under UV light at 254 nm. The degradation process of entacapone in solutions can be described by second-order kinetics under the experimental conditions used in this study. The LC/MS/MS determinations revealed that in the above conditions the photodegraded product formed the geometric isomer of entacapone (Z-entacapone). The obtained results show the importance of appropriate light protection during the drug development process, storage, and handling.
