Ciprofloxacin hydrochloride-loaded ocular silk fibroin liposomes: Formulation, characterisation, in vitro cytotoxicity, and antimicrobial activity

Abstract

Ocular drugs have low absorption because of the unique environment in the eye, making ocular drugs one of the most challenging pharmaceutical initiatives. Liposomes have shown to be a promising ocular drug delivery system over the years because of enhanced drug absorption, biocompatibility, and biodegradability. Utilising a mucoadhesive material alongside liposomes could be a promising strategy to increase the therapeutic efficacy of ocular drugs. The present study aimed to develop a silk fibroin (SF)-coated liposomal formulation as an ocular drug delivery system. Regenerated silk fibroin (a novel biopolymer) was coated on ciprofloxacin hydrochloride-loaded liposomes (CPH-SFLs). Studies were carried out on the morphology, drug encapsulation efficiency, and in vitro drug release. Human corneal epithelial cells (HCEC) were used to examine the cellular adherence and cytotoxicity of CPH-SFLs. CPH-SFLs had an average particle size of 183 ± 3 nm as opposed to 169 ± 4 of blank SFLs. CPH-loaded SFLs lacked the endothermic peak of CPH at 150 °C, indicating that the CPH molecules were trapped in the SF polymeric grid. In the case of the formulations, 25 %–45 % of the medicine was released at a relatively fast pace over the course of the first 4 h and then at a slower rate over the course of the next 12–24 h. CPH-SFLs demonstrated sustained drug release and high in vitro ocular penetration of CPH. The MTT test was conducted to gauge the viability of HCECs, cell viability was higher than 85 %, demonstrating that CPH-SFLs had no adverse effects on HCEC. The observed CPH-SFL adhesions to HCECs were swift and persistent, like the cellular uptake of CPH-SFLs by HCECs. When compared to CPH-solution, the produced formulation CPH-SFLs demonstrated significantly (P < 0.0001) greater susceptibility. The studies concluded that SF-coated liposomes could be the most viable ocular drug delivery in comparison to conventional eye drops.

Keywords

• Silk fibroin
• Liposomes
• Ciprofloxacin HCl
• Ocular drug delivery
• In vitro cytotoxicity
• Antimicrobial activity