Nevirapine nanosuspension: comparative investigation of production methods

Increasing number of antiretroviral drugs coming from high throughput screening besides their high dose has poor solubility profile. Formulation development of these drugs is a major obstacle to their clinical application. To overcome extremely low water solubility and associated poor bioavailability they can be formulated as nanosuspensions. This paper is not only focuses on production of parenteral nevirapine nanosuspensions but also on scaling up of formulations for clinical use. Lab scale (APV LAB 40, 40 mL) and medium scale (Avestin C50, 2 kg) production was performed using piston gap high pressure homogenization (HPH), while the feasibility for pilot scale up was checked using a bead milling technique in continuous mode (PM, Bühler PML-2). Nanosuspension was characterized for particle sizes, zeta potential, crystallanity and stability. The mean particle sizes for lab scale, medium scale and pilot scale production obtained were 481 nm, 429 nm and 211 nm, respectively. Independent of the production method (lab and pilot scale) all processed formulations showed more or less similar zeta potential (~15 mV) in conductivity adjusted water. Long term stability over 1 year showed significant increase in particle size at all storage conditions for lab scale and medium scale production (high energy size reduction) whereas they remained physically stable (with negligible increase) for the milled product (low energy size reduction). As the technology has been scaled up successfully for nevirapine nanosuspension, the product can be considered for commercial exploitation. The prepared nevirapine nanosuspensions can be administered for parenteral or oral use.