Sensory properties analysis of a calcipotriol and betamethasone dipropionate cream vehicle formulated with an innovative PAD Technology for the treatment of plaque psoriasis on the skin and scalp.

Background: In psoriasis, poor treatment adherence is frequently related to low efficacy and limited cosmetic acceptability from the patients' perspective. This study aimed to characterize the sensorial attributes of a calcipotriol (CAL) and betamethasone dipropionate (BDP)-cream vehicle based on polyaphron dispersion (PAD) Technology and to compare them with the conventional ointment and oleogel formulations for psoriasis. Methods: A panel of 16 experts assessed sensory properties at four different stages: appearance, pick up, rub out and afterfeel. Descriptive sensory analysis was used to evaluate relevant attributes. Each attribute was rated on a line scale (range 0-100%). Active ingredients were not used because panellists were healthy volunteers, and vehicle formulations needed to be used instead. Results: CAL/BDP PAD-cream vehicle was evaluated as having a low stickiness, low grease behaviour, good wetness, and good spreadability. Ointment showed the least desirable behaviour regarding these properties. Moreover, once CAL/BDP PAD-cream vehicle was absorbed, the gloss disappeared quickly, leaving low stickiness and a low amount of residue. This afterfeel behaviour was not observed with ointment. The oleogel formulation had good sensory properties, similar to CAL/BDP PAD-cream vehicle, but with lower integrity of shape, lower wetness and higher greasiness. Conclusion: Overall, CAL/BDP PAD-cream vehicle has the desirable requirements for a topical product for the treatment of psoriasis, with better sensory properties than ointment and easier manipulation than oleogel, which may lead to greater acceptance and adherence.

Cubic liquid crystalline structures in diluted, concentrated and highly concentrated emulsions for topical application: Influence on drug release and human skin permeation.

Novel emulsions with a nanostructured continuous phase have been proposed as controlled drug delivery systems to enhance topical delivery of active ingredients avoiding systemic effects. In this study, oil-in-water (O/W) emulsions with two surfactant/water (S/W) weight ratios of 40:60 and 35:65, and oil concentrations of 10 wt% (diluted emulsion), 40 wt% (concentrated emulsion) and 85 wt% (highly concentrated emulsion) have been investigated to identify the presence of liquid crystalline structures and their influence on drug release and skin permeation. The emulsions have been characterized in terms of visual appearance, rheology and drug release. The presence of cubic liquid crystalline structures in emulsions with S/W 40:60 was confirmed by small angle X-ray scattering (SAXS). Rheology results showed a markedly different behaviour in emulsions with S/W 40:60 compared with nonstructured emulsions. A model drug, diclofenac sodium (DS) was successfully incorporated in the emulsions. DS release was studied with hydrophilic and lipophilic membranes, and the amount of DS in the receptor solution was significantly lower in the formulations containing cubic liquid structures. An in vitro skin permeation study with dermatomed human skin showed that emulsions with a nanostructured continuous phase are suitable formulations for topical delivery with DS retention in skin layers. The results indicate that the amount of drug retained in skin structures may be tuned by modification of liquid crystal concentration and emulsion structure.