Slow-release melarsoprol microparticles.

Abstract

The present study compares two methods of preparation of microparticles of melarsoprol for the treatment of the human trypanosomiasis. Melarsoprol is poorly soluble in water and in organic media. Microparticles were formulated with modified O/W and W/O/W methods, Poly(epsilon -caprolactone) microparticles were prepared either with a suspension-in-oil-in-water (S/O/W) solvent evaporation method or by complexation of melarsoprol with methyl ss-cyclodextrin followed by a water-in-oil-in-water (W(CD)/O/W) solvent evaporation method. Results showed a poor incorporation of melarsoprol (2.89 +/- 0.20 microg mg(-1)) using the W(CD)/O/W process, while the S/O/W process allowed achieving 161 +/- 5 microg mg(-1) and seemed to be very effective for the preparation of a sustained release form of melarsoprol. Moreover S/O/W microparticles showed a slow release of the drug in 70% of phosphate buffer pH 7.4, 0.1 M and 30% of propylene glycol (about 50% in 2 h and 80% after 7 h).