Mesoporous nanocrystalline
hydroxyapatite (
nHAp) rods of size 40-75 nm long and 25 nm wide (resembling bone
mineral) were synthesized under microwave irradiation without using any
surfactants or modifiers. The surface area and average pore size of the
nHAp were found to be 32 m(2) g(-1) and 4 nm, respectively.
Rifampicin (RIF) and
ciprofloxacin (CPF) loaded
nHAp displayed an initial burst followed by controlled release (zero order kinetics). Combination of CPF and RIF loaded
nHAp showed enhanced bacterial growth inhibition against Staphylococcus aureus (S. aureus), Staphylococcus epidermidis (S. epidermidis) and Escherichia coli (E. coli) compared to individual agent loaded
nHAp and pure
nHAp. In addition, decreased bacterial adhesion (90%) was observed on the surface of CPF plus RIF loaded
nHAp. The biocompatibility test toward MG63 cells infected with micro-organisms showed better cell viability and
alkaline phosphatase activity (ALP) for the combination of CPF and RIF loaded
nHAp. The influence on cell viability of infected MG63 cells was attributed to the simultaneous and controlled release of CPF and RIF from
nHAp, which prevented the emergence of subpopulations that were resistant to each other. Hence, apart from the issue of the rapid synthesis of
nHAp without
surfactants or modifiers, the simultaneous and controlled release of dual drugs from
nHAp would be a simple, non-toxic and cost-effective method to treat bone
infections.