Combined approach of nanoemulgel and microneedle pre-treatment as a topical anticellulite therapy.

Background and purpose: Cellulite is caused by changes in the metabolism of the fatty tissue beneath the skin. Methylxanthines and retinoids are commonly added to the different anticellulite products. However, their topical permeation into the dermis is limited. Thus, the objective of this research is to formulate a nanoemulgel (NEG) containing a triple therapy of caffeine, aminophylline, and tretinoin as a topical anticellulite product to improve their skin permeation. Furthermore, the influence of microneedles (MNs) as skin pre-treatment on the permeation of the NEG was investigated.

Experimental approach: Various nanoemulsion (NE) formulations were prepared using high-energy ultrasonication with different compositions and sonication amplitudes. Several characterisation tests were employed to select the optimum NE formulation. Then, the optimised NE formulation was incorporated with hyaluronic acid to prepare the NEG, which was, in turn, subjected to various evaluations. An ex vivo permeation study using human skin was performed for the NEG compared to a control preparation of plain gel. Additionally, a microneedling pen was applied as a skin pre-treatment at varying lengths prior to NEG application to examine its impact on the NEG's permeation.

Key results: The selected NEG has a homogenous and consistent texture with no coarse particles, a droplet size of 175.8 nm and polydispersity index (PDI) of 0.19, an optimum pH value of 5.28, high drug content of caffeine, aminophylline, and tretinoin (99.35, 98.48 and 98.05 %, respectively), high drug release values of approximately 100 % within 6 hours, appropriate viscosity, minimum skin irritation, and adequate short-term stability. The ex vivo permeation study showed that caffeine, aminophylline, and tretinoin permeated more and deposited in the skin with higher percentages from the NEG than plain gel. This skin deposition within the dermis was increased by applying the microneedling pen at varying lengths of 0.5, 1, and 2 mm as a skin pre-treatment.

Conclusion: This combined approach of NEG formulation containing a triple therapy of caffeine, aminophylline, and tretinoin, along with MNs application, has the potential to serve as a topical anticellulite product, reducing cellulite formation and improving skin appearance.