Transdermal application of diacerin loaded-terpene enriched invasomes: an approach to augment anti-edema and nociception inhibition activity

This study aimed to formulate diacerein loaded terpene-enriched invasomes (DCN-TINV) to fulfill a fruitful management of osteoarthritis. A 2³ factorial design was adopted, including A: cholesterol concentration (%w/v), B: ethanol volume (mL) and C: phosphatidylcholine: drug ratio as the studied factors. Invasomes were constructed using the thin film hydration technique. Herein, percent entrapment efficiency (EE%), particle size (PS), poly-dispersity index (PDI) and zeta potential (ZP) were statistically analyzed using Design-Expert^® software to select the optimum formula. The selected criteria for detecting the optimum formula were restricting PS (<350 nm), dismissing PDI, magnifying ZP (as absolute value) and EE%. The selected formula was further scrutinized through multiple in-vitro studies, including Fourier-transform infrared spectroscopy, differential scanning calorimetry, pH measurement, stability study, release profile and transmission electron microscopy. Furthermore, the ex-vivo performance was evaluated through ex-vivo skin permeation and deposition. Finally, it was subjected to an array of in-vivo tests, namely Draize test, histopathology, In-vivo skin penetration, edema size, and nociception inhibition measurements. The optimum formula with desirability (0.913) demonstrated EE% (89.21% ± 2.12%), PS (319.75 ± 10.11 nm), ZP (-55 ± 3.96 mV) and a prolonged release profile. Intriguingly, revamped skin permeation (1143 ± 32.11 µg/cm²), nociception inhibition (77%) and In-vivo skin penetration (144 µm) compared to DCN suspension (285 ± 21.25 µg/cm², 26% and 48 µm, respectively) were displayed. The optimum DCN-TINV exhibited plausible safety and stability profiles consolidated with auspicious efficacy for better management of osteoarthritis.