A lipid-and-polymer-based novel local drug delivery system--BonyPid™: from physicochemical aspects to therapy of bacterially infected bones

Bacterial infection of bone may result in bone destruction and is difficult to cure due to poor accessibility to bone of systemically-administrated antibiotic and poor performance of currently available local antibacterial treatments. We developed a novel local drug delivery system based on self-assembly of specific familiar lipids and polymers that encapsulate the desired drug (exemplified by doxycycline). The entrapped doxycycline present in the anhydrous environment of the formulation is fully protected from long-term water-exposure-related degradation. The fine coating of the tricalcium phosphate bone filler by this doxycycline-containing formulation (BonyPid™) is capable of releasing intact and active drug at a steady, zero-order rate for a predetermined period of up to 30 days and in amount sufficient to achieve therapy potentially capable of eliminating the contaminating bacteria. Therefore a clinical evaluation is proposed for testing the efficacy and toxicity of BonyPid for therapy of bacterial bone infections.