Formulation development and characterization of dual drug loaded hot-melt extruded inserts for better ocular therapeutic outcomes: Sulfacetamide/prednisolone

The present investigation was intended to formulate and evaluate a hot-melt extruded (HME) bioadhesive ophthalmic inserts containing a fixed-dose combination of Prednisolone Sodium Phosphate (PSP) and Sulfacetamide Sodium (SA) to improve the treatment outcomes of multiple ocular bacterial infections. The inserts were prepared using FDA-authorised biocompatible polymers, including Polyox WSR N10 LEO NF (polyethylene oxide; PEO), Klucel(TM) HF (hydroxypropyl cellulose; HPC-HF), and Ethocel(TM) (Ethylcellulose; EC). The inserts were then assessed for physicochemical characteristics, weight variation, surface pH, uniformity of thickness, drug content, swelling index, thermal analysis, drug-excipient compatibility, moisture uptake and loss, surface morphology, mucoadhesive strength, in vitro release, ex-vivo transcorneal permeation and deposition, and stability. The HPC-HF and EC-containing inserts extended the release of both drugs compared to PEO-N10-based inserts that showed the release of the loaded amount of both drugs immediately (<1 h). All fabricated inserts were stable over 90-day storage at room temperature (25 degrees C) and accelerated conditions (40 degrees C) for drug content and thermal behavior. The developed PSP-SA inserts exhibited optimum bioadhesive strength and smooth surface favorable for topical ocular application. Ex vivo transcorneal permeation studies using freshly isolated rabbit corneas demonstrated that the extended-release inserts slowed down the transcorneal flux of the drug in comparison to the immediate-release inserts and the commercial solution eyedrops. Overall, the inserts were fabricated using a solvent-free, scalable, and continuous manufacturing process and could reduce the frequency of administration to once-daily application, affording a new topical delivery vehicle with prolonged antibacterial and anti-inflammatory activity during ocular bacterial infections treatment.