Abstract Development and validation of a simple and fast method of high-performance liquid chromatography with diode array detection (HPLC-DAD) for the simultaneously analysis of rutin, avobenzone, and octyl p-methoxycinnamate is presented. These substances were separated using a Kromasil C18 (250×4.6 mm, 5 μm) column, methanol: water (88:12 v/v) as the mobile phase, and a flow rate of 0.8 mL min−1. The experiment was performed at room temperature and elution was under isocratic conditions. Quantification was performed by external calibration at the wavelength of 325 nm. The validated parameters included linearity, selectivity, precision (repeatability), intermediate precision, accuracy, limit of detection, limit of quantification and robustness. The results of validation were statistically treated using the Action Stat version 3.5.152.34. The selectivity was also evaluated in the presence of two cyclodextrins (2-hydroxypropyl-β-cyclodextrin and β-cyclodextrin sulfobutyl ether sodium). The absence of parallelism between the curves of octyl p-methoxycinnamate in the absence and presence of the β-cyclodextrin sulfobutyl ether sodium in the mobile phase revealed interference from this matrix, thereby indicating the necessity of validating the method in the presence of this, and other matrices. The proposed method was selective, linear, precise, accurate, and robust for the simultaneous determination of rutin, avobenzone, and octyl p-methoxycinnamate.

In this work the evaluation of the dissolution profile of captopril-hydrochlorothiazide and zidovudine-lamivudine associations were carried out by multivariate spectroscopic method. The models were developed by partial least square regression from 20 synthetic mixtures using mean-centered spectral data. The external validation was accomplished with 5 synthetic mixtures shown mean prevision error of about 1%. Good agreement was observed in the analyses of commercial drugs (content uniformity and dissolution profile), considering the results obtained by the standard chromatographic method, with prevision error lower than 10%.

A ineficácia clínica de muitos medicamentos tem servido de alerta para estudos mais profundos sobre os componentes da formulação, processos empregados e características físico-químicas dos fármacos. O objetivo deste trabalho foi avaliar a liberação in vitro de comprimidos de fosfato de primaquina disponíveis no Brasil para tratamento da malária, e o desenvolvimento de novas formulações de liberação convencional. Embora os comprimidos de fosfato de primaquina estudados tenham sido aprovados pelos critérios propostos pela Farmacopéia Americana (2006) para o teste de dissolução, não apresentaram desempenho adequado para o perfil de dissolução, mostrando retenção do fármaco durante a liberação. Os resultados indicam a existência de problemas nos comprimidos de fosfato de primaquina analisados, podendo sugerir como um dos fatores responsáveis pelo aparecimento de resistência dos parasitas.

The clinical inefficacy of many medications has served to highlight the need for deeper studies on the formulation components, processes used and physicochemical characteristics of drugs. The objective of this study was to evaluate the in vitro release of primaquine phosphate from tablets available in Brazil for treating malaria, and the development of new formulations for conventional release. Although the primaquine phosphate tablets studied had been approved according to the criteria proposed by the United States Pharmacopoeia (2006) for the dissolution test, they did not present adequate dissolution performance characteristics, in that there was drug retention during the release process. The results indicate the existence of problems in the primaquine phosphate tablets analyzed, and it may suggest that this is one of the factors responsible for the appearance of parasite resistance.

Voltamogramas de redissolução catódica de cefaloglicina em meio ácido exibem uma única onda de redução em potenciais próximos da descarga do eletrólito (-1.0 V). Entretanto, o fármaco pode ser determinado indiretamente em meio alcalino (pH 10) através do complexo formado entre cefaloglicina e Hg(I) gerado na superfície do eletrodo sob potencial de acúmulo positivo (Eac= +0.20 V). Uma curva de calibração linear no intervalo de 0.122 a 1.22 mg/mL foi obtida para cefaloglicina em tampão B-R pH 10 utilizando-se tempo de acúmulo de 30 seg e potencial de acúmulo de +0.20 V. O método mostra alta reprodutibilidade e sensibilidade com desvio padrão relativo de 1,4 % para 5 determinações de 5x10-7 mol/L de cefaclor e limite de detecção de 5,17 ng/mL.

Cephaloglycin in B-R buffer pH < 4 is reduced at HMDE very close to the electrolyte discharge (-1.0 V). Nevertheless, in alkaline medium (pH 10) a peak at -0.6V is observed when cephaloglycin is accumulated at accumulation potentials close to +0.20V by formation of an adsorbed mercury complex. The accumulation of this complex is recommended for use in the indirect determination of cephaloglycin by cathodic stripping voltammetry in the range 0.122 to 1.22 mg/mL with pre-concentration for 30 sec at accumulation potential of +0.20V. The detection limit was calculated to be 5,17 ng/mL (n= 3). The relative standard deviation determined from five determinations at the 5x10-7 mol/L level was 1.4 %.