Vesicular powder as carrier for doxycycline hydrochloride and metronidazole combination therapy.

In this study, vesicular proniosomal powder encapsulating doxycycline hydrochloride (DH) and metronidazole (MT) combination therapy was developed using different types of spans, cholesterol (CH) and maltodextrin as a carrier. Proniosomal powder was free flowing and spherical in shape. The surfactant structure affected the entrapment efficiency of both drugs with highest value of Sp 60 proniosomes of 45.16% and 42.64% for DH and MT, respectively. Incorporation of CH influenced vesicle stability and permeability with optimum concentration of 10 mole%. Increasing the surfactant loading from 1 mM to 3 mM resulted in a significant decrease in the amount of drugs (mg) entrapped per mM lipid (from 9.95 to 1.13 and from 8.88 to 1.22 for DH and MT, respectively). Longer chain length surfactants produced larger vesicles. Surfactant hydrophilicity affected zeta potential. Both drugs were molecularly dispersed in the proniosomal powder with no chemical interaction with other components. Proniosomal powder was stable at 2-8 °C for three months.