Design, optimisation and <i>in vivo</i> evaluation of tazarotene loaded emulgel formulation for the treatment of acne

Acne vulgaris is a common dermatological disorder, with current treatments often limited to poor skin penetration, instability, irritation and suboptimal therapeutic outcomes. There is a pressing need for advanced drug delivery systems that can overcome these limitations and enhance treatment efficacy. This study aimed to develop and optimise a novel tazarotene-loaded emulgel formulation, combining the advantages of emulsions and gels to achieve controlled drug release, improved stability and superior clinical performance in topical acne therapy. The formulation was prepared using the incorporation method and optimised through the Box-Behnken statistical design (BBD). Three independent variables, such as Carbopol 940 (<i>X</i>₁), Span 80 (<i>X</i>₂) and Tween 80 (<i>X</i>₃), were assessed for their effects on drug release (<i>Y</i>₁) and viscosity (<i>Y</i>₂). The optimised formulation exhibited desirable characteristics, including pH: 6.6 ± 0.3, viscosity: 28,945 cPs, spreadability: 6.17 ± 0.02 cm², extrudability: 18 ± 2.49 g/cm² and drug content: 85.46 ± 4.02%. <i>In vitro</i> studies demonstrated 87.59 ± 2.6% drug release over 7 h. A skin irritation test in mice confirmed its dermatological safety, with no signs of erythema or oedema. Anti-acne efficacy, evaluated using a <i>Propionibacterium acnes</i>-induced murine model, revealed complete lesion clearance, outperforming a marketed gel. These findings firmly establish the tazarotene-loaded emulgel as a safe, effective, and superior topical treatment for acne.