CHARACTERIZATION OF VERAPAMIL HYDROCHLORIDE ENTRAPPED IN POLY (LACTIDE-CO-GLYCOLIDE) (PLGA) PARTICLES

The optimized microparticles of Verapamil hydrochloride entrapped in Poly(lactide-co-glycolide) (Verapamil HCl-PLGA) was prepared through solvent displacement method and lyophilization. The optimization parameters for the formulation include particle size, polydispersity index, zeta potential, and entrapment efficiency. The final product was further characterized based on percent particle recovery, redispersibility, percent drug loading, drug release kinetics, and morphology. Increasing the PLGA 75:25 concentrations resulted to an increase in the particles size, polydispersity index and entrapment efficiency, and a decrease in zeta potential. The increase in poloxamer 188 concentration led to a decrease in zeta potential and an increase in the entrapment of the drug. Lastly, the increase in the pH of the non-solvent phase resulted to an increase in particle size. The addition of sucrose  led to an unfavorable increase in the particle size and polydispersity index and a decrease in zeta potential and entrapment efficiency after lyophilization. The final product of the process was a heterogeneous sized (<10µm) irregularly shaped particles with an acceptable particle recovery, redispersibility, and percentage drug loading, but with poor release kinetic property. The Verapamil HCl-PLGA microparticles prepared through solvent displacement method and lyophilization were able to meet the conditions for lymphatic transport: entrapment in a lipophilic polymer in terms of particle size requirement (<10µm). Thus, it is possible that through polymeric drug formulation, the low bioavailability of Verapamil HCl due to hepatic first-pass effect may be addressed.