LC determination of entacapone in tablets: in vitro dissolution studies.

The aim of the study was to develop and validate a dissolution procedure for entacapone-coated tablets. Several conditions such as medium composition, pH, surfactant concentration, and rotation speed were evaluated. The best dissolution conditions were achieved using apparatus 2, 900 mL of medium containing acetate buffer pH 5.3 at a rotation speed of 50 rpm, and a reversed-phase liquid chromatographic method for the quantification of the drug from the dissolution test, as well as to evaluate the dissolution profiles for tablets. The procedure was validated by specificity, linearity, accuracy, repeatability, intermediate precision, and robustness. The chromatographic method employed an Agilent Eclipse XDB RP-18 (150 × 4.6 mm i.d., particle size 5 µm) with a mobile phase consisting of water pH 3.0 and acetonitrile (65:35, v/v) at a flow rate of 2.0 mL/min. The dissolution procedure developed and validated was adequate for its purpose and could be applied for quality control for entacapone-coated tablets because there is no official monograph.

Morfoanatomia das folhas de Dodonaea viscosa Jacq., Sapindaceae / Morph-anatomy of the leaves of Dodonaea viscosa Jacq., Sapindaceae

Dodonaea viscosa Jacq., Sapindaceae, é uma planta tradicionalmente utilizada como antifebril, anti-reumática e antimicrobiana. Neste trabalho foram determinados parâmetros morfo-anatômicos, por análise macro e microscópicas, das folhas de Dodonaea viscosa, com o objetivo de auxiliar sua diagnose como insumo farmacêutico. Macroscopicamente as folhas apresentam limbo com forma lanceolada, margem inteira, consistência áspera e venação eucamptódroma. O pecíolo é curto, reto e em seção transversal é triangular com os ângulos arredondados. Microscopicamente destaca-se a cutícula com formações lenticulares, os tricomas glandulares com quatro células na base, os tricomas tectores unicelulares de ápice afilado, os estômatos higrofíticos dispostos apenas na face abaxial da epiderme, o parênquima paliçádico com até três camadas de células e os feixes vasculares com xilema envolto por floema e cordões de parênquima que ligam um maciço central de células de parênquima a uma bainha de esclerênquima. Estas características morfo-anatômicas, quando analisadas em conjunto, contribuem no controle botânico de qualidade das folhas de Dodonaea viscosa como insumo farmacêutico.

Dodonaea viscosa Jacq., Sapindaceae, is a plant traditionally used as anti fever, anti- rheumatic and antimicrobial. This work determined morpho-anatomical parameters, by macro and microscopic analysis of Dodonaea viscosa leaves, aiming to reach their diagnosis as pharmaceutical input. Macroscopically, the leaves have a lanceolate shape limb, full margin, rough consistence and venation eucamptodromous. The petiole is short, straight and in transversal section it is triangular with round angles. Microscopically, the lenticullar formation cuticle is seen with prominence, the glandular thricomes are seen with four cells on the base, the non-glandular unicellular thricomes are seen with pointed apex, the higrophitic stomatas are disposed in the lower surface epidermis only, the palisade parenchyma show up to three-cell layers and vascular bundles with xylem involved by phloem and parenchyma lines which bound a central mass of parenchyma cells to a sclerenchyma sheath. This morph-anatomical characteristic, when analyzed in group, contributes to the botanical quality control of Dodonaea viscosa leaves as pharmaceutical input.

LC/MS/MS study for identification of entacapone degradation product obtained by photodegradation kinetics.

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.