Study Of Long-acting Risperidone-Loaded PLGA Microspheres For Injection

Risperdione is a new atypical antipsychotic drug available for schizophrenia management. Modest improvements in negative and to a lesser extent, cognitive symptoms have also been demonstrated, with diminution of positive symptoms, lower dosage and better safty. Despite these gains, the administration of risperidone is still oral pill or oral solution. As a special group of patients with schizophrenia, it may be difficult for them to take that regularly. This paper will combine this new kind of atypical antipsychotic drug risperidone and new drug delivery system microsphere to a new administration of risperdone: extended release microspheres. The injection is administrated intramuscularly every 2 weeks with the risperionde being released systemically over time, with the characters of convenience, extended release, better bio-availability, the steady of plasma drug concentration and none of first pass effect. The major content and the results are as follow:Risperidone microspheres were prepared with the method of emulsion-solvent evaporation by using DCM as oil phase. The new concept of Laminar Flow Emulsion was utilized to avoid the irregular movement of fluent and the microspheres prepared with Laminar Flow Emulsion are spherical with lower extent of diameter distribution, which benefits the controlling of the microsphere quality. Sudden cooled process as well as Clean process were added to make sure of the control of burst release efficiently. Testing methods of characters (diameter, span, drug-loading and etal) of risperidone microspheres were also developed.With the help of Central composite design and analysis of STASTICA6.0, the influences of many preparation factors (PLGA concentration, stiring, PVA concentration, O/W, drug loading and etal) to the responses (diameter, span, loading efficiency) were systematically analysed. Best values of preparing factors were determined and that was PLGA concentration 100mg/mL;PVA concentration 3%;O/W 1/5;stiring 800r/min;drug loading in theory 20%. Characters of PLGA microspheres were diameter 35μm;SPAN 0.65;drug loading 15.5%,smooth and...