Assessment of the effect of applied vehicle on the process of release of bearberry extract components from semisolid bleaching preparations applied on skin
Magdalena Piechota-Urbańska, Wiktor Urbański, Justyna Kołodziejska, Grażyna Samczewska, Aneta Berner-Strzelczyk
Katedra Farmacji Stosowanej Uniwersytetu Medycznego w Łodzi
Arbutin contained in dry extract of bearberry (Arctostaphylos uva ursi L. Sprengel) is a skin-whitening agent which can be used in dermatology and cosmetology. The assumption of the carried out study was to work out new prescriptions of semisolid preparations applied on skin, containing dry extract of bearberry. The aim of the study was to assess the effect of the applied vehicle on the process of release of bearberry extract components from the produced formulations. The formulations were prepared on the basis of three types of vehicles: hydrogel, lipophilic cream and hydrophilic cream. Physicochemical parameters of the produced formulations were tested dependently on the kind of the vehicle. Viscosity parameters were determined using cone-plate digital rheometer. Extensibility was estimated with an extensometer. Potentiometric method was used to measure pH. The rate of release of dry extract components through a semipermeable membrane to the acceptor fluid was tested in vitro. Spectrophotometric method was used for determination of the quantity of the released therapeutic substances.
The quality of the produced formulations was estimated on the basis of the test results and evaluation of diffusion of the active components through dialysis membrane to acceptor fluid. From among the suggested preparations, the process of therapeutic substances release from a dry extract of bearberry to the acceptor fluid was the most effective from hydrogel formulation P1+M. There was not always observed a strict dependence between rheological properties characterizing the produced formulations and the quantity of therapeutic substances released from them. The quantity of the released substance depends to a large extent on the type of the vehicle.
Key words: semisolid preparation for skin application, bearberry, extracts, rheology, pharmaceutical availability