RESUMO
A high-performance liquid chromatographic method is described for the analysis and identification of related impurities in pharmaceutical-grade 6 alpha-methylprednisolone acetate (MPA). Eight MPA impurities derived from synthesis and/or degradation processes were identified. The method is compared to other analytical procedures recently proposed for the European Pharmacopoeia.
Assuntos
Cromatografia Líquida de Alta Pressão , Metilprednisolona/normas , Metilprednisolona/análiseRESUMO
A study of a multiple high-performance liquid chromatographic procedure for the separation of 30 different corticosteroids is described. Normal- and reversed-phase general methods operating in a wide polarity range have been developed for the rapid screening of multicomponent mixtures. The complementary application of both normal- and reversed-phase methods could permit clarification of uncertainty deriving from analyses performed by only one method.
Assuntos
Corticosteroides/análise , Cromatografia Líquida de Alta Pressão/métodos , Corticosteroides/síntese químicaRESUMO
For a particular form (amorphous phase) of physical acting substances the water solubility, in conditions very close to the in vivo ones, has been compared with corresponding biological activities. The reciprocal of the above parameter shows a good correlation with various physico-chemical, biochemical and pharmacological parameters of xanthinic compounds, analgesic alkaloids, barbiturates, sulphonamides. The solubility of the crystalline phase cannot be correlated with the biological activity: the ratio between these two solubilities shows this inability.
Assuntos
Alcaloides/metabolismo , Barbitúricos/metabolismo , Sulfonamidas/metabolismo , Xantinas/metabolismo , Alcaloides/análise , Barbitúricos/análise , Disponibilidade Biológica , Fenômenos Químicos , Físico-Química , Cristalização , Solubilidade , Sulfonamidas/análise , Xantinas/análiseRESUMO
Problems related with controlled release dosage forms are reported. The need for a standard criteria regarding both nomenclature and dissolution test is pointed out. The purpose is to permit a suitable control of the controlled release characteristics.
Assuntos
Preparações de Ação Retardada , Química FarmacêuticaAssuntos
Anestésicos Locais/efeitos da radiação , Materiais Biocompatíveis , Bupivacaína/efeitos da radiação , Ácido Láctico , Ácido Poliglicólico , Polímeros , Anestésicos Locais/administração & dosagem , Bupivacaína/administração & dosagem , Espectroscopia de Ressonância de Spin Eletrônica , Microesferas , Copolímero de Ácido Poliláctico e Ácido PoliglicólicoRESUMO
The analytical characteristics of cimetidine tablets were studied. A high-performance liquid chromatographic method was developed in order to assay cimetidine and its related impurities simultaneously. A reversed-phase system and diode-array detector were used.
Assuntos
Cromatografia Líquida de Alta Pressão/métodos , Cimetidina/análise , Cromatografia Líquida de Alta Pressão/estatística & dados numéricos , Contaminação de MedicamentosRESUMO
The activity coefficients "gamma" aqueous solution and the diffusion rate constants (Kd) from artificial gastric and intestinal juices were measured for eleven sulfonamides; the corresponding absorption rate constants (Ki) were then calculated. The activity coefficient was correlated with various parameters, such as the n-octanol/water and isoamyl acetate/water partition coefficients, and the absorption constant. The activity coefficient "gamma" plays an important role on the global biological activity, even if partly depending upon chemical interactions. Constant ratios (about 10%) referred to solubility of the sulfonamidic compounds in the "amorphous state" were regarded as available in blood for biological activity, regardless of the respective binding with plasma proteins.