Microscopic and spectral study of the release kinetics of betamethasone dipropionate from vaterite carriers in aqueous media

The development of novel delivery systems for water-insoluble glucocorticosteroids (GCSs) enabling their transportation to the inflammatory site in skin is essential for improvement of their therapeutic efficiency. In this context, the design of different carriers for GCS encapsulation, which allows enhancement of the local drug concentration and, thus, reduction of the overall dose and side effects for this GCS, is of particular interest. Here, we propose to use porous metastable submicron vaterite particles, since such carriers possess a high sorption capacity and ability to release the encapsulated drug during their degradation. We demonstrated the possibility of their efficient loading with betamethasone dipropionate (BD) glucocorticosteroid. A comprehensive assessment of the BD encapsulation was performed using a combination of various spectroscopic methods and electron microscopy. In addition, we optimized the methodology for studying the BD release kinetics in model aqueous media in vitro. Namely, the introduction of a nonionic surfactant as a solubiliser to the aqueous suspension of the BD-loaded carriers provided an increase in accuracy for spectroscopic determination of the drug amount released at different time intervals. The data obtained in the study of drug release kinetics using the proposed method demonstrated a good correlation with the results of carriers’ morphology monitoring by means of scanning electron microscopy and energy dispersive X-ray spectroscopy.