Improved dermal delivery of pentoxifylline niosomes for the management of psoriasis: Development, optimization and in-vivo studies in imiquimod induced psoriatic plaque model

Abstract

Psoriasis is an inflammatory disorder of skin. In mild cases of psoriasis topical route is mostly preferred for the treatment. But delivery of drugs through psoriatic skin is very difficult. Hydrophilic nature of pentoxifylline makes its permeation difficult via this route. Niosomes are the vesicular systems, reported to improve the sustained, controlled and target delivery of drugs. In this study, Pentoxifylline niosomes were, developed, optimized and tested in-vitro and in-vivo on an imiquimod induced psoriatic model to improve the dermal delivery of pentoxifylline for the enhanced management of psoriasis. Thin film hydration method was used for the preparation of niosomes. Prepared niosomes were evaluated for their percentage encapsulation efficiency, size and polydispersity index. Finally, optimization was done by the application of Box-Behnken. Optimized pentoxifylline loaded niosomes were prepared using cholesterol and tween 80 (ratio 0.662), 14.5 mg of soya lecithin and 10 mg of pentoxifylline. Optimized niosomes were further studied for ex-vivo permeation, skin-deposition and in-vivo antipsoriatic effect on imiquimod induced psoriatic models. The optimized niosomes' size and percentage entrapment efficiency were in the range of 173.5-± 28.36 nm and 83.2 ± 5.5%, respectively. Excised goat's skin was opted to study the ex-vivo permeation and skin deposition of niosomes. Significant amount of drug was not detected in the ex-vivo permeation studies. Skin deposition studies on excised goat skin showed deeper and significant deposition of pentoxifylline niosomes in epidermal layers than the free drug. The in-vivo studies performed on the imiquimod induced psoriasis in Swiss albino mice, pentoxifylline loaded niosomes demonstrated a significant decrease in the inflammation of epidermis and stratum corneum as well as reduction in the Psoriasis area – Severity Index as compared to the control and pentoxifylline solution groups. The results clearly indicates that optimized pentoxifylline niosomes can be used for the better management of psoriasis.