Design and characterization of microcrystals for enhanced dissolution rate of celecoxib.

Poor aqueous solubility and bioavailability of drugs are one of the important factors affecting the absorption of drugs and consequently their therapeutic effectiveness. Celecoxib is a widely used anti-inflammatory agent, with special use in rheumatoid arthritis. It belongs to biopharmaceutical classification system (BCS) class II drug with low solubility and high permeability. The present study was aimed to prepare and characterize the microcrystals of celecoxib, employing in situ micronization technique by rapid solvent change approach to enhance the solubility and dissolution rate and to optimize the solvent and anti-solvent ratio (v/v) using hydrophilic stabilizers such as guar gum, maltodextrin and PVP K30. The prepared formulations were evaluated for percentage crystal yield, mean particle size, drug content and in vitro dissolution studies. Amongst the formulations prepared (F1-F9), F6 formulation containing maltodextrin as stabilizing agent at 0.1% w/v concentration with 1:6 ratio of solvent to anti-solvent (v/v) respectively was considered as optimized formulation in which percentage drug release was found to be 89.33% within 60 minutes in comparison with that of the pure drug dissolution of 30.26% only within 60 minutes. Characterization studies like SEM, DSC and XRD indicate the solubility enhancement of celecoxib microcrystals due to decrease in particle size when compared to that of pure drug. FT-IR spectroscopy studies revealed that there is no chemical interaction between the drug and stabilizer and crystalline habit modification occurs in the microcrystals without any polymorphic changes.