Chemotherapeutic efficacy of nanoparticle encapsulated antitubercular drugs

Our objective was to evaluate the chemotherapeutic potential of oral poly lactide-co-glycolide (PLG, a synthetic polymer) nanoparticle encapsulated ethambutol in combination with PLG-nanoparticle encapsulated-(rifampicin + isoniazid + pyrazinamide) in a murine tuberculosis (TB) model. Our formulation was prepared by the multiple emulsion technique and administered orally to mice for the biodistribution, pharmacokinetic, and chemotherapeutic studies. A single oral administration of the formulation to mice could maintain sustained drug levels in the plasma for 5 days and in the organs (lungs, liver, spleen) for 7-9 days. There was a striking improvement in the pharmacokinetic parameters such as half-life and mean residence time as compared with free drugs. The relative/absolute bioavailability of the 4 antituberculosis drugs was enhanced several fold. Repeated administration of the formulation did not produce any hepatotoxicity as assessed on a biochemical basis. In M. tuberculosis H37Rv infected mice, just 3 oral doses of the 4-drug formulation administered at every 10th day resulted in undetectable bacilli in the organs replacing 28 conventional doses of free drugs. We concluded that polymeric nanoparticle based oral 4-drug combination bears significant potential to shorten the duration of TB chemotherapy, besides reducing the dosing frequency.