Verapamil hydrochloride nanoparticles formulated with chitosan and sodium alginate by an ionic gelation method

Purpose: To formulate chitosan-based nanoparticles for extended release of verapamil so as to reduce its dosing frequency. Methods: Nanoparticles of chitosan and sodium alginate loaded with verapamil HCl were synthesized using the ionotropic gelation method. The formulations were optimized by cross linking of tripolyphosphate with chitosan, and CaCl2 with sodium alginate at different concentrations. The ionic gelation method was used to produce seven different formulations. The best formulation for nanoparticles preparation involved using 0.06 % sodium alginate with 18 mM CaCl2 and of chitosan: TPP (5:1 ratio). The compatibility of verapamil HCl with sodium alginate and chitosan was tested using FTIR. Results: Verapamil nanoparticles had a direct correlation with the polymer concentrations used. A 5:1 ratio of chitosan:TPP resulted in a particle size of 173 nm, and high drug entrapment. The size of verapamil nanoparticles prepared with sodium alginate was 186 nm (p = 0.02). Cross-linking agent played an important role in the preparation of the nanoparticles. Scanning electron micrographs showed that the nanoparticles were coalesced with one another, and had rough surfaces. Chitosan-based formulations had an entrapment efficiency in the range of 38.63 – 50.58 %, while the entrapment efficiency of sodium alginate-based formulations was 11.70 – 40.57 % (p 0.43). Conclusion: Verapamil nanoparticles have been successfully formulated by ionic gelation method using natural polymers. The nano-formulations did not exhibit polymer-drug interactions, but manifest extended drug-release profiles