Quality by design driven development of lipid nanoparticles for cutaneous targeting: a preliminary approach

Fungal infections are the fourth common cause of infection affecting around 50 million populations across the globe. Dermatophytes contribute to the majority of superficial fungal infections. Clotrimazole (CTZ), an imidazole derivative is widely preferred for the treatment of topical fungal infections. Conventional topical formulations enable effective penetration of CTZ into the stratum corneum, however, its low solubility results in poor dermal bioavailability, and variable drug levels limit the efficacy. The aim was to increase dermal bioavailability and sustain drug release, thereby potentially enhancing drug retention and reducing its side effects. This work evaluated the CTZ loaded solid lipid nanoparticles (SLN) consisting of precirol and polysorbate-80 developed using high pressure homogenization and optimized with QbD approach. Prior to release studies, CTZ-SLNs were characterized by different analytical techniques. The laser diffractometry and field emission scanning electron microscopy indicated that SLNs were spherical in shape with mean diameter of 450 ± 3.45 nm. DSC and XRD results revealed that the drug remained molecularly dispersed in the lipid matrix. The CTZ-SLNs showed no physicochemical instability during 6 months of storage at different temperatures. Further, the Carbopol with its pseudoplastic behavior showed a crucial role in forming homogenous and stable network for imbibing the CTZ-SLN dispersion for effective retention in skin. As examined, in-vitro drug release was sustained up to 24 h while ex-vivo skin retention and drug permeation studies showed the highest accumulation and lowest permeation with nanogel in comparison to pure drug and Candid^® cream. Further, the in-vivo antifungal efficacy of nanogel suggested once-a-day application for 10 days, supported by histopathological analysis for complete eradication infection. In summary, the findings suggest, that nanogel-loaded with CTZ-SLNs has great potential for the management of fungal infections caused by Candida albicans.