Design and optimization of self-microemulsifying drug delivery system (SMEDDS) of felodipine for chronotherapeutic application

The objective of this research work was to design, develop and optimize the self micro-emulsifying drug delivery system (SMEDDS) of Felodipine (FL) filled in hard gelatine capsule coated with polymer in order to achieve rapid drug release after a desired time lag in the management of hypertension. Microemulsion is composed of a FL, Lauroglycol FCC, Transcutol P and Cremophor EL. The optimum surfactant to co-surfactant ratio was found to be 2:1. The resultant microemulsions have a particle size in the range of 65-85 nm and zeta potential value of -13.71 mV. FL release was adequately adjusted by using pH independent polymer i.e. ethyl cellulose along with dibutyl phthalate as plasticizer. Influence of formulation variables like viscosity of polymer, type of plasticizer and percent coating weight gain was investigated to characterize the time lag. The developed formulation of FL SMEDDS capsules coated with ethyl cellulose showed time lag of 5-7 h which is desirable for chronotherapeutic application.

O objetivo desse trabalho de pesquisa foi planejar, desenvolver e otimizar sistema de liberação de fármaco auto-microemulsificante(SMEDDS) de felodipino (FL) em cápsulas de gelatina dura revestidas com polímero, a fim de obter liberação rápida após tempo desejado no manejo da hipertensão. A microemulsão é composta de FL, lauroglilcol FCC, Transcutol P e Cremophor EL. A proporção ótima de tensoativo e de co-tensoativo foi de 2:1. As microemulsões resultantes têm tamanho de partícula na faixa de 65-85 nm com potencial zeta de -13,71 mV. A liberação de FL foi ajustada adequadamente, utilizando-se polímero independente de pH, como etilcelulose com ftalato de dibutila como plastificante. A influência das variáveis da formulação, como viscosidade do polímero, tipo de plastificante e ganho percentual de peso do revestimento foi investigada para caracterizar o intervalo de tempo de liberação. A formulação de cápsulas de FL SMEDDS revestidas com etilcelulose mostrou intervalo de tempo de liberação de 5 a 7 horas, o que é desejável para uma aplicação cronoterapêutica.

Natural product and drugs interactions, its clinical implication in drug therapy management

The interaction of natural products and drugs is a common hidden problem encountered in clinical practice. The interactions between natural products and drugs are based on the same pharmacokinetic and pharmacodynamic principles as drug-drug interactions. Clinically important interactions appear to involve effects on drug metabolism via cytochrome P-450 isoenzymes, impairment of hepatic or renal function, and other possible mechanisms. To effectively counsel patients on interactions involving natural products, physicians, and pharmacists should be familiar with the most commonly used products, and have access to information on more obscure products. In this review, we describe details of drugs interaction with natural products and its impact on drug therapy management

Felodipino en el tratamiento de la hipertensión arterial esencial de adultos mayores / Felodipine in the treatment of essential arterial hypertension in elders

Felodipine is a calcium channel inhibitor with high vascular selectivity. To studu the effectiveness of felodipine in the treatment of essential hypertension in subjects older than 64 years old, 50 subjects were studied. After a washout period of 4 weeks, subjects received a placebo for 2 weeks followed by the active drug given in an initial dose of 5 mg/day, adjusted to 10 and 20 mg every 21 days if normal blood pressure levels were not attained. Compared to the placebo period, Felodipine treatment reduced blood pressure from 173ñ7.5/102ñ3.3 mm Hg to 158ñ6.3/91ñ4.4 mm Hg. There was no orthostatic reduction of blood pressure and 87 percent of subjects attained systolic and diastolic pressure levels below 140 and 90 mm Hg respectively. Adverse reactions (edema, cephalea and flushing) were reported by 38 percent of subjects and in 3, the drug was discontinued. There were no changes in laboratory parameters during the treatment period. Quality life improved during treatment in the items of concentration, health status perception, mood, physical condition, depression, effects of hypertension on life evets and initiative. Felodipine is effective in the treatment of elders with essential hypertension