ABSTRACT
Multiple emulsions have been proposed to have numerous uses including their use for enhancement of bioavailability or as a prolonged drug delivery system. But the inherent instability of this system needs to be overcome before they find potential application in pharmaceuticals. Multiple emulsions are often stabilized using a combination of hydrophilic and hydrophobic surfactants. The ratio of these surfactants is important in achieving stable multiple emulsions. Atorvastatin was selected as a model drug to study the potential of multiple emulsion to improve bioavailability with the hypothesis that improvement of drug release profile will reflect the enhancement of bioavailability of the drug. The objective of this study was to prepare multiple emulsion of Atorvastatin by two step emulsification using nonionic surfactants, and evaluate for stability, percentage drug entrapment, in-vitro & ex-vivo drug release. Different formulation variables like type & proportion of primary & secondary emulsifier and phase volume ration of internal phase:external phase; and process variables like speed & time of stirring during primary & secondary emulsification were optimized to get stable multiple emulsion with high entrapment efficiency. The study concluded that stable multiple emulsion with high entrapment efficiency can be prepared by two step emulsification method using Span60 as primary and Tween80 as secondary emulsifier at 30:70 phase volume ratio of internal phase:external phase with optimized speed of stirring at 5000 r/min for 10 mins for primary emulsification and 1500 r/min for 7 mins for secondary emulsification.
ABSTRACT
The effects of protein malnutrition on the quantitative aspects of the myenteric plexus in the ileum of adult Rattus norvegicus were assessed. Thirty 90-day-old rats were divided into two groups: Control Group (CG, n=15) and Experimental Group (EG, n=15). The CG received 26 percent protein chow and the EG received 4 percent protein chow for 90 days. At the end of the experiment, the animals from the CG weighed 369.63±26.33, and the ones from the EG 215.34±56.31. The ileum was submitted to Giemsa, NADH- and NADPH-diaphorase technique in order to evidence nervous cells in the whole-mount preparations. Animals from the EG presented a 41.75 percent body weight loss in relation to the CG as well as 17.6 percent length reduction for the ileum-jejunum. Moreover, the organ was 41 percent lighter for the EG. Giemsa-stained neurons were 17.02 percent more concentrated in the EG (p>0.05). NADH-diaphorase-stained neurons were 26.6 percent more concentrated in the EG (p<0.05), while the NADPH-diaphorase were 26.28 percent more concentrated in this group (p<0.05).
Avaliou-se o efeito da desnutrição protéica sobre o número de neurônios mientéricos do íleo de ratos adultos. Foram utilizados 30 animais (90 dias de idade), divididos em dois grupos: controle (GC, n=15) e experimental (GE, n=15), sendo oferecido ao GC ração com teor protéico de 26 por cento e, para o GE, ração com 4 por cento de proteína, durante 90 dias. Os animais do grupo controle pesaram 369,63±26,33g e o experimental 215,34±56,31g. Preparados de membrana do íleo foram submetidos à técnica de Giemsa, NADH- e NADPH-diaforase. Os animais do GE apresentaram perda de peso de 41,75 por cento, em relação ao GC e redução do comprimento do jejuno-íleo de 17,6 por cento, além disso, o órgão apresentou-se 41 por cento mais leve no GE. Os neurônios corados com a técnica de Giemsa apresentaram-se 17,02 por cento mais concentrados no GE (p>0,05). Os neurônios NADH-diaforase apresentaram-se 26,60 por cento mais concentrados no GE (p<0,05). E os neurônios NADPH-diaforase apresentaram-se 26,28 por cento mais concentrados neste grupo (p<0,05).