Formulation and in-Vitro Evaluation of Celecoxib-Loaded Niosomal Matrix-Type Transdermal Patches for the Management of Osteoarthritis

Celecoxib, a selective cyclo-oxygenase-2 (COX-2) inhibitor widely prescribed for the symptomatic management of osteoarthritis, is a Biopharmaceutics Classification System (BCS) Class II drug whose poor aqueous solubility and cardio-gastrointestinal liabilities on chronic oral dosing limit its clinical utility. The present study aimed to formulate and evaluate celecoxib-loaded niosomal matrix-type transdermal patches as a non-invasive alternative capable of sustaining drug release and reducing systemic exposure. Niosomes were prepared by the thin-film hydration technique using Span 60 and cholesterol at three molar ratios (1:1:1, 1:2:1 and 1:2:2); the 1:1:1 formulation (F1) showed the highest entrapment efficiency (93.24%), a mean particle size of 616.0 nm, a polydispersity index of 0.315 and a zeta potential of −32.7 mV, and was selected for patch fabrication. Matrix-type transdermal patches were prepared by the solvent-casting method using HPMC K100 and PVP K30 as film-forming polymers, optimised through a 3² factorial design (nine batches, F1–F9). Fourier-transform infrared spectroscopy confirmed the absence of significant drug–excipient interaction. The optimised patch (F3, high HPMC K100 and high PVP K30) exhibited satisfactory physicomechanical properties (weight 192.6 ± 2.1 mg, thickness 0.53 ± 0.01 mm, folding endurance 290 ± 6, surface pH 5.86 ± 0.04, drug content 98.40 ± 0.45%) and released 71.0% of celecoxib over 12 h in-vitro, compared with 85% released from a plain (non-vesicular) patch over the same period, confirming that vesicular entrapment sustained drug release. Release data best fitted the Higuchi model (R² = 0.992), with a Korsmeyer–Peppas exponent (n = 0.68) indicative of non-Fickian (anomalous) transport combining diffusion and polymer relaxation. These findings suggest that incorporating niosomes into a matrix-type transdermal patch is a promising controlled-release approach for transdermal delivery of celecoxib in osteoarthritis management and warrants further ex vivo permeation and in vivo evaluation.