Preparation and characterization of microparticles of PHBV with streptomycin
Candido, C. B. 1; Marcato, P. D1; Duran, N. 1,2
1Laboratório de Química Biológica, UNICAMP, Campinas, S.P; 2Química Biológica e Laboratório de Biotecnologia, NCA, Universidade de Mogi das Cruzes, Mogi das Cruzes, S.P.
Objective:The aim of this work was to prepare and to characterize systems which sustained liberation containing streptomycin (STM), a hydrophilic drug having antibiotic activity used in the tuberculosis treatment. The STM was encapsulated in biodegradable microparticles of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) by the double emulsion water/oil/water method (w/o/w) with evaporation of the solvent.
Methods:The STM was encapsulated in microparticles of PHB-9.8% HV (MW 23 kDa) by double emulsion water-oil-water (w/o/w) and solvent evaporation method using agitation in probe sonication. The organic solvent was evaporated for 12 hours under mechanicall stirring. Several parameters in the method were altered. The first one was the addition of 20% (v/v) of acetone in the organic phase. The second one was the use of agitation in ultra turrax and evaporation of organic solvent under reduced pressure.
Results:By double emulsion and solvent evaporation method microparticles of PHBV were obtained. These particles were characterized by SEM exhibiting rugose surface and spherical morphology with size of 7.5±2.8 mm measured by LS Particle Size Analyzer. The encapsulation efficiency was 43±4% measured by capillary electrophoresis. Porous and smoothly microparticles of PHBV were obtained with the addition of the acetone in the organic phase. The size of these particles was 11.5±2.4 mm. This alteration might increase the speed of liberation of the drug, showing the possibility of the release control of this. The agitation change by ultra turrax to evaporation of the organic solvent in rotaevaporator reduced the size of the particles to 5.8±2.4 mm. This reduction can be due to the increase speed of diffusion of the organic solvent for the aqueous phase when the system is under reduced pressure.
Conclusion:The double emulsion and solvent evaporation method showed to be efficient in the microparticles formation and in the encapsulation of the hydrophilic drug STM. It was demonstrated that alterations in the method, like the addition of a co-solvent and the way of evaporation of the solvent, change the morphology and the diameter of the microparticles.
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