Enhancement of storage stability of cisplatin-loaded protransfersome topical drug delivery system by surface modification with block copolymer and gelling agent

The present investigation aimed at formulation development and surface modification of a cisplatin (CDDP)-loaded protransfersome system to improve the storage stability. CDDP-loaded protransfersome dispersion was prepared and surface modification was done by incorporation of Pluronic F-68 (PF-68 modified system) and combination of Pluronic F-68 and Carbopol 940 (PF-68 modified protransfersome CP-940 gel). All the three formulations were evaluated for 6-month storage stability and characterized for physicochemical properties. Results showed that particle size of protransfersome dispersion was found to increase more rapidly, from 709.9 +/- 0.3 to 1129 +/- 0.7 nm, than polymer-modified system. Viscosity of formulations was found to be in the range of 58.6 cp +/- 1.2 to 122.2 cp +/- 0.7. Maximum % CDDP content was found in PF-68-modified protransfersome CP-940 gels (87.34 +/- 0.9 to 86.01 +/- 1.3). Results confirm that PF-68-modified protransfersome CP-940 gel is the best achieved formulation for storage at 4 degrees C.