Studies on biodegradable polymeric nanoparticles of risperidone: in vitro and in vivo evaluation.
OBJECTIVE
The aim of this work was to develop extended-release risperidone nanoparticles for parenteral delivery (intravenous) and to reduce the dose-dependent extrapyramidal side effects of risperidone.


METHODS
Polymeric nanoparticles containing risperidone made of poly (epsilon-caprolactone) were designed by the nanoprecipitation method using polymeric stabilizers (poloxamers). The in vivo efficacy of prepared formulations and the risperidone solution was studied by administering them intravenously to apomorphine-treated mice. Extrapyramidal side effects of the risperidone and its formulations were also studied.


RESULTS
The particle size of the prepared nanoparticles ranged between 99 and 304 nm. Approximately 78-85% drug-encapsulation efficiency was achieved when risperidone was loaded at 1.7-4.1% by weight of the polymer. During in vivo studies, prepared risperidone-containing formulations showed a significant prolonged antipsychotic effect than that of risperidone solution, also having less extrapyramidal side effects.


CONCLUSIONS
The prolonged effect of risperidone was obtained from the nanoparticles of risperidone administered by the intravenous route and this may improve the treatment of psychotic disorders by dose reduction.
Muthu
Madaswamy S
MS
Institute of Medical Sciences, Department of Pharmacology, Banaras Hindu University, Varanasi - 221005, India. muthubits@rediffmail.com
Singh
Sanjay
S
D020341:Absorbable Implants; D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects*; D004058:Diffusion; D004337:Drug Carriers / Q000737:chemistry*; D004339:Drug Compounding / Q000379:methods; D004353:Drug Evaluation, Preclinical; D007275:Injections, Intravenous; D051379:Mice; D053758:Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D011091:Polyesters / Q000737:chemistry*; D018967:Risperidone / Q000008:administration & dosage* / Q000737:chemistry*
D004337:Drug Carriers; D011091:Polyesters; C016240:polycaprolactone; D018967:Risperidone