5-fluorouracil (5-FU) is used to treat scleral and episcleral fibroblast proliferations (scarring process) in the eyes. Frequent washing of the conventional solution results in limited drug access to the eyes. Taguchi and central composite design (CCD) oriented optimized mucoadhesive cationic elastic liposomes were prepared and characterized. The optimized F-CEL8 (composed of 85 mg of dipalmitoyl-phosphatidylcholine, 15 mg of sodium cholate, 10 mg of 5-FU, 7 mg of ethanol, and 883 mg of buffer) and its gel were studied for in vitro and ex vivo drug release profiles as compared to the drug solution and the liposomes. In vitro hemolysis and Draize studies corroborated safety concerns. An in vivo pharmacokinetics study was studied in rats. Each mL of F-CEL8 contained dipalmitoyl-phosphatidylcholine (X1), sodium cholate, and ethanol to deliver 10 mg of 5-FU with optimal vesicle size, low polydispersity index (PDI), and high zeta potential (ZP). The %EE value of spherical F-CEL8 was quite high (82.3 ± 7.1 %) as compared to liposomes (∼53 %) due to the large volume of the inner aqueous chamber of vesicles. F-CEL8-gel exhibited relatively high viscosity for slow and sustained release for 24 h as compared to others. The percent permeation of 5-FU from the solution, F-CEL8, F-CEL8-gel, and the liposomes were found to be 28.6 ± 4.6 %, 69.6 ± 7.4 %, 76.89 ± 12.4 %, and 54.8 ± 5.3 %, respectively. All isotonic formulations did not exhibit hemolysis and irritation to the eyes. The gel illustrated the highest values of pharmacokinetics parameters as compared to the solution and the liposomes, which may be attributed to the maximum residence time achieved through electrostatic interaction (the vesicle internalization with the mucosal layer of eyes).
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