Purpose: Cocrystallisation of drug with coformers is a promising approach to alter the solid sate properties of drug substances like solubility and dissolution. The objective of the present work was to prepare, formulate and evaluate the piroxicam cocrystal by screening various coformers.Methods: Cocrystals of piroxicam were prepared by dry grinding method. The melting point and solubility of crystalline phase was determined. The potential cocrystal was characterized by DSC, IR, XRPD. Other pharmaceutical properties like solubility and dissolution rate were also evaluated. Orodispersible tablets of piroxicam cocrystal were formulated, optimized and evaluated using 32 factorial design.Results: Cocrystals of piroxicam-sodium acetate revealed the variation in melting points and solubility. The cocrystals were obtained in 1:1 ratio with sodium acetate. The analysis of Infrared explicitly indicated the shifting of characteristic bands of piroxicam. The X-Ray Powder Diffraction pattern denoted the crystallinity of cocrystals and noteworthy difference in 2θ value of intense peaks. Differential scanning calorimetry spectra of cocrystals indicated altered endotherms corresponding to melting point. The pH solubility profile of piroxicam showed sigmoidal curve, which authenticated the pKa-dependent solubility. Piroxicam cocrystals also exhibited a similar pH-solubility profile. The cocrystals exhibited faster dissolution rate owing to cocrystallization as evident from 30% increase in the extent of dissolution. The orodispersible tablets of piroxicam cocrystals were successfully prepared by direct compression method using crosscarmelose sodium as superdisintegrant with improved disintegration time (30 sec) and dissolution rate.Conclusion: The piroxicam cocrystal with modified properties was prepared with sodium acetate and formulated as orodispersible tablets having faster disintegration and greater dissolution rate.

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Models for predicting the solubility of drugs in monosolvents and their mixtures have a practical importance in design and development of new products in pharmaceutical industries. Thus, present investigation pertains to the utility of a correlative model for solubility prediction of etoricoxib (ETR). The molar solubilities of ETR in a number of monosolvents and various mass fractions of their binary aqueous solvent mixtures were determined using the shake-flask method at 298.2 K. Densities of ETR saturated solutions in the monosolvents and their binary solvent mixtures were measured and then correlated using a well-established method proposed by Jouyban and Acree. Overall mean percentage deviations (OMPDs) between experimental and predicted values were 3.4 % for the molar solubilities and 0.1 % for the densities of the saturated solutions.

Experimental molar solubility of etoricoxib (ETR) in monosolvents such as glycerin, methanol (MeOH), polyethylene glycol 200 (PEG 200), polyethylene glycol 400 (PEG 400), polyethylene glycol 600 (PEG 600), propylene glycol (PG), and their aqueous binary solvent systems in various mass fraction compositions along with the solute-free and saturated solution densities were measured at 298.2 K. The resulting mole fraction solubility and density data were further correlated and predicted with the Jouyban−Acree model. Overall mean percentage deviations (OMPDs) between experimental and calculated mole fraction solubilities were 3.5%. The solute-free density of the monosolvents and their aqueous binary solvent systems were employed to train the model and then the densities of the saturated solutions were predicted. Moreover, OMPDs for back calculated solute-free densities and predicted saturated solution densities were 0.07% and 0.40%, respectively. Thus, the Jouyban−Acree model have potential use in preformulation and formulation studies during which solubility and density calculations are important physicochemical properties for design and development of new drug products in pharmaceutical industries. The simulated data could also be employed in crystallization and other related process design in the pharmaceutical/chemical industry.

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