RESUMEN
In this study, commercial available poly(epsilon-caprolactone)s and poly(d,l-lactide)s of different molecular masses were used. Slow release devices (SRD) were obtained as rods of suitable diameters by extrusion of polymer-drug mixtures (75:25, w/w) which were prepared by the solution casting method. The rods were coated by dipping them in a methylene chloride solution of the core polymer. The in vitro release of the selected drugs, isometamidium chloride (IMM) and ethidium bromide (EtBr) from such rods was carried out in phosphate buffer (PB) pH 7.4 at 37 degreesC. The release data show that the release of IMM is faster than for EtBr. During the first stage, the release of IMM is governed by osmotic pressure whereas the release of EtBr is mainly diffusion controlled. The in vitro release of these drugs is governed by polymer matrix degradation at the later stage of the release process. The in vitro release could be controlled by drug loading, polymer molecular mass, polymer mixtures, coating thickness and device geometry.
Asunto(s)
Poliésteres/química , Tripanocidas/administración & dosificación , Materiales Biocompatibles , Análisis Diferencial Térmico , Implantes de Medicamentos , Etidio , Peso Molecular , Fenantridinas , SolubilidadRESUMEN
The prophylactic activity of a subcutaneously implanted slow release device, containing homidium bromide, was assessed in rabbits, challenged with different stocks of T. congolense, and compared with the classical treatment of 1 mg homidium bromide/kg b.w. intramuscularly. The prophylactic activity of the intramuscular injection was less than a month, while the slow release device protected the rabbits against seven challenges with T. congolense during a period of more than 300 days.