Development of a new solid lipid nanoparticle formulation containing retinoic acid for topical treatment of acne.

The development of solid lipid nanoparticles (SLN) containing all-trans retinoic acid (RA) is an interesting approach to topical treatment of acne. SLN has potential for controlled release and follicular penetration, which can reduce adverse effects in comparison with conventional formulations. However, the encapsulation efficiency (EE) of RA in SLN is usually low, unless a high surfactant/lipid ratio is used. The aim of this work was to develop SLN with high EE using a low surfactant/lipid ratio. Different formulations of RA-loaded SLN were prepared using glyceryl behenate as lipid matrix. The particle size, EE, zeta potential and differential scanning calorimetry (DSC) were investigated. High EE in SLN was obtained with addition of amines. These results indicate that the utilization of amines is an interesting approach to improve the EE of RA in SLN using a low surfactant/lipid ratio.