Modification of the physicochemical properties of minocycline hydrochloride ointment with cyclodextrines for optimum treatment of bedsore.

Modification to find the best physicochemical properties of minocycline hydrochloride ointment for optimum treatment of bedsore was investigated by coformulating various types of cyclodextrins (CyD) in the ointment base. It was found that the drug release rate from the ointment base was modified according to the preparation method of ointment base and the type of CyD admixed. The physicochemical properties, such as viscosity, elution volume, water absorption of ointment base were also modified by those factors. The mechanism of physicochemical modification with CyD was explained by the structural change of ointment base and the change of surface tension of emulsifying agent solution with the CyD. The stability of ointment was investigated by confirming the reproducibility of drug release rate after storage at ambient and cooled temperature conditions. In conclusion, a fused mixed ointment with beta-CyD was found to be preferable for treatment of bedsore, because of the improved drug release rate, lowered viscosity and increased elution volume of the resultant ointment.