Taste Masking of Enalapril Maleate by the Precipitation Method

Taste masking of bitter or unpleasant drugs is an important prerequisite to improve patient compliance, especially for children and elderly patients. We aimed at obtaining taste-masked microparticles intended for incorporation into orodispersible tablets (ODTs). We selected the precipitation method using enalapril maleate (ENA) as a model bitter-tasting drug and Eudragit EPO® as a pH sensitive polymer.

The aim of this study was to obtain microparticles with enalapril maleate by the precipitation method in order to mask the bitter taste of the drug.

Nine models of enalapril maleate – Eudragit EPO® microparticles were prepared by the precipitation method at varied drug-polymer ratios. The models were characterized in terms of size, shape, production yield, drug content, encapsulation efficiency and moisture content. Fourier-transformed infrared spectroscopy, powder X-ray diffraction and differential scanning calorimetry were used to analyze possible interactions in the complex. In vitro drug release in simulated salivary fluid and in vivo taste evaluation in rats were realized to prove taste masking.

The particle size distribution varied from 266.9 µm to 410.9 µm. The shape of the resulting particles was irregular. The production yield varied from 23.6% to 78.2%. The drug content ranged between 2.3% to 4.8%, encapsulation efficiency increased from 1.6% to 9.0%. In vitro drug release data indicated significant taste masking.

Some of the obtained microparticles by the precipitation method showed satisfactory taste masking efficiency, which proved the taste masking feasibility of this method.