Calcipotriol is a vitamin D analogue and is used as active pharmaceutical ingredient in pharmaceutical formulations against psoriasis. It exists in two pseudopolymorphs, anhydrate and monohydrate, the latter of which, can be found in the commercially available cream Dovonex®. The percentage of the API in the cream is as low as 0.005 wt %.
Methodologies were developed for monitoring calcipotriol’s hydrate state in creams exhibiting pharmaceutical strength considerably lower than the detection ability of all commonly used techniques. The methods were based on X-Ray Powder Diffraction and micro-Raman spectroscopy. Transformation of calcipotriol anhydrate crystals to monohydrate was found to take place in the presence of cream’s excipients.
(EL)
University of Patras
