The effect of glycol extract of arnica on rheological parameters and pharmaceutical availability of morphine hydrochloride from anhydrous absorptive ointments
Grażyna Samczewska, Magdalena Piechota-Urbańska
Zakład Farmacji Aptecznej, Katedra Farmacji Stosowanej, Uniwersytet Medyczny w Łodzi
Introduction. Ointments applied on painful wounds are expected to have not only analgesic but also anti-inflammatory and healing potential. Due to unsatisfactory durability of the ointment with aqueous solution of morphine hydrochloride (MH), anhydrous ointments were produced in which propylene glycol (propano-1,2-diol) was the solvent of morphine salt and active substances in the composition of arnica herb.
Aim. To test the effect of glycol extract of arnica (AE) on rheological parameters, pH of produced ointment according to own prescription and on the pharmaceutical availability of morphine hydrochloride (MH).
Material and methods. Two ointments (MC and MCW) of variable content of anhydrous lanolin but of constant content of glycol solution of morphine hydrochloride (MH) and glycol extract of arnica (AE) were tested. Extensometric method was used to test the extensibility of the formulations. Viscosity parameters were determined with a digital cone-plate rheometer. Spectrophotometric method was used to test morphine pharmaceutical availability.
Results. Glycol extract of arnica (AE) caused nearly twofold increase of morphine hydrochloride (MH) pharmaceutical availability. The per cent lanolin content also affected the process of MH release. From among the tested ointments the diffusion process was most effective at 16% lanolin content.
Key words: ointments, morphine hydrochloride, glycol extract of arnica, rheology, pharmaceutical availability