After 2^3 factorial optimization of a celecoxib topical emulgel, formulation F6 released 93.2% cumulatively over 36 hours and delivered 75.6% across porcine skin

The study established a celecoxib topical emulgel formulation and selected F6 as the optimal batch, showing 93.2±1.2% cumulative in vitro release over 36 hours versus the 45% reported for the standard formulation. Whereas oral celecoxib is limited by negligible aqueous solubility, CYP2C9 first-pass metabolism, and gastrointestinal, renal, and cardiovascular adverse effects, this work focuses on systematic optimization and characterization of a topical delivery formulation. Evidence comes from in vitro release testing of eight batches (F1–F8) using vertical Franz diffusion cells across synthetic dialysis membranes, with release kinetics fitted to the Higuchi model (R2=0.996).

F6 achieved 75.6±1.9% cumulative transdermal delivery (4267±107 μg/cm2) through excised porcine skin while retaining 12.8±1.1% in the skin, indicating both permeation and local retention. The report pairs in vitro release with ex-vivo skin permeation and cutaneous retention, so formulation evaluation extends beyond the release profile alone. Evidence comes from ex-vivo porcine skin permeation experiments reporting cumulative delivery percentage, delivered amount per unit area, and cutaneous retention, each with standard deviations.

All eight batches fell within a skin-compatible pH range (6.18±0.04 to 6.42±0.04), with viscosity from 21,450±120 to 29,580±180 cP, spreadability from 17.6±0.30 to 24.6±0.42 g·cm/s, and drug content from 97.42±0.64% to 99.48±0.29%. These physicochemical and content metrics provide batch-level quantitative description of the formulation's suitability for topical application. Evidence comes from measurements of physical appearance, pH, rheological behavior, spreadability, and content uniformity across F1–F8, all reported as mean±standard deviation.

Preformulation confirmed drug purity (melting endotherm at 161.8 °C, λmax 252 nm), and ATR-FTIR and DSC showed preservation of characteristic functional peaks (3336 cm−1 N–H stretch, 1348 cm−1 SO2 stretch) without chemical degradation; accelerated stability testing (40±2 °C/75±5% RH for 3 months) showed no significant degradation or physicochemical alteration (p>0.05). Together, the drug-excipient compatibility and stability data support physicochemical consistency of the emulgel under storage and use conditions. Evidence comes from ATR-FTIR, DSC, forced degradation studies, and accelerated stability testing per ICH Q1A(R2), with stability differences reported as p>0.05.

The results are intended for formulation development of celecoxib topical anti-inflammatory delivery: they apply to an emulgel system using HPMC as gelling agent, liquid paraffin as oil phase, and Tween 20/Span 20 as emulsifier, evaluated in vitro with Franz diffusion cells across synthetic dialysis membranes, ex vivo through excised porcine skin, and under accelerated stability at 40±2 °C/75±5% RH for 3 months. For researchers and developers screening topical semisolid formulations and conducting in vitro evaluation, the paper offers comparable formulation variables, physicochemical metrics, and release kinetics as a starting point for further in vivo work and scale-up.

This is an incomplete reading scope: the summary is based only on the loaded abstract-level description, without the full text, figures, or statistical detail, so the specific effect sizes linking formulation variables to response metrics, statistical comparisons among batches, and the number of replicates in the ex-vivo permeation experiments remain open questions. In addition, whether the in vitro release and ex-vivo porcine skin permeation results extrapolate to human skin, inflamed skin, and long-term use settings would require in vivo studies and clinical evaluation; 3-month accelerated stability data also cannot substitute for long-term stability testing.