Preparation And Quality Study Of Felodipine Self-emulsifing Drug Delivery System

A new calcium antagonist, felodipine, has the effect of vascularselectivity, can effectively reduce peripheral vascular resistance andblood pressure, and increase in coronary blood flow. The efficacy of thedrug is definite and with low toxic and adverse effects. The drug hasoccupied more than7%market share in the domestic antihypertensive drugs,showing a steady growth trend and good market prospect. The developmentof its new drug delivery systems has significant social and economicbenefits.The dosage forms of felodipine in China are tablets, capsules etc.,and till now there is no the development of self-emulsifying formulation.The aim of this study is to determine the self-emulsifying formulationby screen and optimize the oil phase and the surfactant, and then to dothe dissolution test using the final optimized formulation.The method of preparing the oral solid self-emulsifying formulationis built.The self-emulsifying powder of felodipine is obtained by spraydrying, and then filled into hard gelatin capsules. By the choices of thesolid carrier and the proportion between solid carrier and felodipineSEDDS, the optimal formulation is screened.The method of in vitro analysis is built, and the quality of theself-emulsifying formulation is studied. The self-emulsifying speed isevaluated by measuring the scattered light intensity of the particles indifferent times. The emulsion particles are about419nm in size via thecharacterization of an optical microscope, fully satisfying with theself-emulsifying formulation standard. Moreover, the dissolution issignificantly improved compared to the tablet.The stability of self-emulsifying capsules is studied, by using theappearance, self-emulsifying situation, particle size, contentdetermination, and dissolution as the key points. The effect of severalfactors (high temperature, high humidity, bright light), accelerated andlong-term test on them is determined. Except bright light (because thefelodipine is unstable when exposed to light), the appearance, particlesize, self-emulsifying situation, content, and dissolution show no significant change The results show that the quality of self-emulsifyingcapsules, felodipine, is stable.In addition, the pharmacokinetic and bioavailability of felodipineself-emulsifying capsule are tested in3groups of rats in vivo. Thebioavailability of self-emulsifying formulation is36.3%, which is about7.6times of that of the tablet.