Abstract
Background: Discontinuation and poor compliance with long-term oral medicine are major therapeutic issues in psychosis treatment. Poorer long-term outcomes may result from non-compliance as well as a higher chance of relapse. In order to sustain therapeutic drug plasma levels, co-administration of oral antipsychotics is necessary for commercially available longacting injections of second-generation antipsychotics, as they have a lag period of approximately three weeks during the drug release process.
Methods: Poly(lactic-co-glycolic acid) (PLGA) encapsulated microspheres loaded with risperidone were fabricated in the current research for intramuscular administration. The single emulsion solvent evaporation technique was applied for the fabrication of microspheres. Risperidone microspheres were prepared using PLGA grade 75:25. Particle size, drug content and entrapment efficiency with a central composite design were the main optimization parameters for the formulation. The microspheres were characterized by different techniques, namely Fourier transform infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC), X-ray diffractometry (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The drug content, entrapment efficiency, morphology, particle size, and in vitro release profiles, along with release kinetics of the risperidone microspheres, were studied.
Results and Discussion: The microspheres produced by the single emulsion solvent evaporation approach show smooth and spherical morphology, with particle size ranging from 3 μm to 6 μm, drug content of 99.7%, and entrapment efficiency of 98.2% with little burst release of 3% to 10%, providing drug release for 45 days and exhibiting zero order release kinetics and Korsmeyer- Peppas model for non-fickian drug release from the polymeric matrix. By applying the Quality by Design (QbD) approach and formulation parameters, microspheres with appropriate particle size, morphology, enhanced drug content, entrapment efficiency and desirable drug release profile for depot formulation can be obtained successfully.
Conclusion: The optimized microspheres, in comparison to the marketed Risperdal Consta™, show enhanced potential for a better depot formulation, which can further improve patient compliance.
Graphical Abstract
