Development of niacinamide cosmetic bioadhesive emulgel using QbD approach.

Objective: The aim of the present study was to develop a cosmetic bioadhesive emulgel to incorporate niacinamide (NMD), based on the combination of sodium hyaluronate and carbomer, using the Quality by Design (QbD) approach.

Methods: It was decided to design first a bioadhesive vehicle and after selecting the best formulation, to load the NMD into the optimized final emulgel. The potential interaction reported in the literature between the selected bioadhesive polymers was investigated by Fourier transform infrared spectroscopy and Raman confocal microscopy. The effect of formulation variables on quality attributes (phase separation by mechanical stress, adhesion, viscosity and spreadability) of the emulgels was studied. Response-surface methodology was applied to optimize the formulation. After optimization, the final NMD emulgel was further characterized by rheometry assay, and ex vivo bioadhesion properties and skin absorption of NMD using human skin.

Results: No relevant interaction between both bioadhesive polymers at the working conditions was found. Emulgel formulations were physically stable, showed uniform spreadability and appropriate viscosity and detachment force values. A high percentage of the dosage of NMD in the optimized emulgel was accumulated between the skin surface and its upper layers over 24 h. In addition, no evidence of permeation through the full skin was found, which complied with the desired low systemic distribution.

Conclusions: NMD was successfully vehiculized in a bioadhesive emulgel developed using the QbD approach. No significant changes in the critical quality attributes of the bioadhesive vehicle were observed after the incorporation of the active ingredient. The product, designed to present an increased residence time on the application site, provides a time frame to facilitate its performance, enabling the active ingredient to remain accumulated between the skin surface and its upper layers. Finally, and most importantly, QbD, a time-and cost-saving development approach that leads to high-quality products, proved to be an invaluable tool in this scientifically driven cosmetic project.