Taste masking of enalapril maleate by microencapsulation in Eudragit EPO^® microparticles.

Abstract

Microencapsulation is one of the most commonly used taste masking techniques. It can be accomplished by various methods, including coacervation, solvent evaporation, extrusion and spray-drying. Enalapril maleate, a bitter-tasting ACE-inhibitor, is available worldwide in conventional tablet formulations and as oral solution in the USA. The purpose of this study was to develop enalapril-loaded microparticles using spray-drying and to test their taste masking potential. Eudragit EPO^® was used as a taste masking polymer for the preparation of a drugpolymer suspension. The suspension was then spray-dried under the following conditions: inlet temperature 65 °C, outlet temperature 30 °C, aspiration 100% and pump rate 10%. The drug-to-polymer ratio was varied and seven different microparticle models were developed. The yield of spray-dried particles ranged from of 51.3 to 85.4%, drug loading varied from 7.75 to 24.69% and encapsulation efficiency ranged from 58.5 to 95.7%. The particle size varied between 5.00 μm and 17.47 μm and the moisture content varied between 7.1% and 10.3%. <i>In vitro</i> taste assessment revealed minimal or no ENA release in artificial saliva. <i>In vivo</i> studies (with experimental animals and healthy volunteers) were used to evaluate the taste masking potential of spray-dried microparticles of enalapril maleate and Eudragit EPO^®.