Andrographolide, a novel bioactive phytoconstituent encapsulated in sustained release biodegradable nanoparticles

Polymeric nanoparticles are advantageous in cancer therapy as they improve the physicochemical properties of drugs and consequently their behaviour in-vitro and the bioavailability of drugs. Andrographolide is a bioactive phytoconstituent widely used in the treatment of various tumours. However, the clinical efficacy by oral administration is contrasted by its biopharmaceutical properties. Hence an alternative dosage form and route of administration is investigated in the present study to enhance its therapeutic efficacy. Sustained release injectable andrographolide-loaded biodegradable poly(epsilon-caprolactone) (PCL) nanoparticle suspension was prepared by a solvent displacement process using poly(ethylene oxide) -poly(propylene oxide)-poly(ethylene oxide) (PEO-PPO-PEO) triblock polymeric stabiliser (Pluronic (R) F-68/Pluronic (R) F-127). The nanoparticles were characterised in terms of particle size, encapsulation efficiency, zeta potential, surface morphology and crystallinity. In-vitro drug release studies were carried out in presence and absence of the enzyme Candida rugose lipase in phosphate-buffered saline (PBS, pH 7.4) at 37 C using the dialysis bag diffusion technique. The obtained suspended nanoparticles were spherical in shape with particle size of 226 +/- 2 to 339 +/- 5 nm and zeta potential -25.2 +/- 1.6 to -27.7 +/- 1.3 mV. Higher value of Q(25hr) (cumulative percentage release at the end of 25 h) and lower values of t(50%) and t(80%) (time required for 50% and 80% w/w drug release) indicated the suitability of PCL nanoparticles in controlled release, which followed diffusion mechanism. The study suggested the applicability of PCL nanoparticles to improve the biopharmaceutical properties of phytoconstituents in cancer chemotherapy.