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

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%. In vitro taste assessment revealed minimal or no ENA release in artificial saliva. In vivo 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®.

Preparation and study of poly(vinyl acetate) and poly(styrene) nanosized latex with indometacin.

During the last decade the number of investigations on the preparation and application of more effective drug release systems on the basis of nanocarriers from biocompatible and biodegradable polymers are considerably increasing. This is notably in force for practically water insoluble drugs to be applied in liquid forms (eye solutions for an example). The aim of the work presented was the preparation of model poly(vinyl acetate) and poly(styrene) nanosupports for indometacin and their potential inclusion in eye drops. The polymers are synthesized as nanosized latex by a radical polymerization of the monomers in the presence of indometacin. It is proved that the low polymerization temperature and initiator used do not influence indometacin structure and properties. The nanoparticles were characterized by attenuated total reflection Fourier transform infrared spectroscopic analyses, atomic force microscopy, scanning electron microscopy and transmission electron microscopy. The size of the latex particles was around 200 nm, determined by the scan electron microscopy. The indometacin delivery rate from the supports discussed in aqueous solutions was determined at pH 7.4. The change of this rate, in comparison with that for a pure drug substance, was established also as well as its dependence on the nature of the carrier.

Biochemical and morphological studies on the effects of anthocyans and vitamin E on carbon tetrachloride induced liver injury.

The effects of the natural antioxidants-anthocyans and vitamin E (in a solubilized pharmaceutical form) on carbon tetrachloride-induced liver injury in rats are studied. The changes in the activity of serum transaminases (ALAT and ASAT), the content of the reduced glutathione and cytochrome P-450 as well as the intensity of the processes of lipid peroxidation are assessed. The anthocyans exert a protective effect comparable to that of vitamin E on liver cells. The favorable effects of the combination of the antioxidants on the content of the reduced glutathione and on the processes of lipid peroxidation are more intensely expressed. The morphological changes occurring in hepatocytes correlate with the results of the biochemical studies. It is evident that both substances have a marked hepatoprotective activity.