Formulation development and in Vitro–Ex vivo characterization of hot-melt extruded ciprofloxacin hydrochloride inserts for ocular applications: Part I

Abstract

This study developed, optimized, characterized, and evaluated bioadhesive, hot-melt extruded (HME), extended-release ocular inserts containing ciprofloxacin hydrochloride (CIP-HCL) to improve the therapeutic outcomes of ocular bacterial infections. The inserts were fabricated with FDA-approved biocompatible, biodegradable, and bioadhesive polymers that were tuned in different ratios to achieve a sustained release profile. The results revealed an inverse relationship between the Klucel™ hydroxypropyl cellulose (HPC, 140,000 Da) concentration and drug release and extended-release profile over 24 h. The CIP-HCL-HME inserts presented stable drug content, thermal behavior, surface pH, and release profiles over three months of room-temperature storage and demonstrated adequate mucoadhesive strength. SEM micrographs revealed a smooth surface. Bacterial growth was not observed on the samples during the in vitro release experiment (0.5–24 h), indicating that a minimum inhibitory concentration (MIC) of 90 against Pseudomonas aeruginosa was achieved. Ex vivo transcorneal permeation studies using excised rabbit corneas revealed that the prepared ocular inserts prolonged the transcorneal flux of the drug compared to commercial eye drops and immediate-release inserts and could reduce the administration frequency to once daily. Therefore, the inserts could increase patient compliance and exhibited prolonged antibacterial activity and thus could provide better therapeutic outcomes against ocular bacterial infections.