A comparative study of top-down and bottom-up approaches for the preparation of nanosuspensions of glipizide

Glipizide nanosuspensions were prepared by both liquid antisolvent precipitation and media milling technique using bead mill. From this study it was concluded that ratio of polymer to drug, milling time and milling speed played significant role in controlling the zeta potential of nanosuspension prepared by media milling whereas, milling time and milling speed were considered to be significant factors for controlling particle size distribution d (90) of nanosuspension. In the bottom up process ratio of surfactant to drug and speed of mixing played a significant role in controlling the zeta potential of glipizide whereas ratio of polymer to drug and speed of mixing were considered to be the significant factors that affect the particle size distribution d (90) of nanosuspension. An increase in particle size distribution was observed with the optimized nanosuspension prepared by liquid antisolvent precipitation method when tested under accelerated conditions (40 °C at 75% RH for 6 months) as compared to media milling method. The X-ray diffraction data shows no form conversion of the drug due to processing parameters involved in the production of nanosuspension. The formulated nanosuspension has shown a faster dissolution profile (98.97 using bottom up and 96.44% using top down method in 10 min), relative to that of pure glipizide (20.17% in 10 min), mainly due to the formation of nanosized particles.