ABSTRACT

Background: Diclofenac is a well-established NSAID that belong to class II BCS which low aqueous solubility. Cocrystallization is one method to improve the solubility of its drug. Recently, it have been reported the innovation of diclofenac acid-proline cocrystal (DPC) which has the 7.65-times higher than of the pure compound.  However, solubility is still the same as diclofenac sodium (ND) that were widely has been used in the dosage forms. Objective: This study aimed to observe whether cocrystal formation can occur not only in AD but also ND in the hope of obtaining new crystalline with higher solubility and improved dissolution than DPC and ND. Materials and Methods: The experiment was begun by interaction screening between ND and PRO using an electrothermal. Cocrystal was made by solvent drop grinding method with some solvent and characterized using FTIR, PXRD, and DSC. Furthermore, to assess the usefulness of new cocrystal, solubility test and dissolution test in gastric and intestine condition were carried out. Results: L-proline (PRO) indicated to form a new cocrystal with ND in the equimolar ratio. Morphologically, the new phase NDPC is thin rod, compared to ND which has a square-shape and PRO with its needle-shape. The specific peak of FTIR resulted in shift wavenumber on 3456 cm^-1 and  1415 cm^-1. Diffractogram pattern showed the new peaks on 4.31⁰; 7.22⁰; 10.43⁰; 13.03⁰; 14.21⁰; 17.33⁰; 17.87⁰; 24.06⁰; 26.29⁰ and a new endothermic peak of the thermogram on 85.6 ⁰C. Solubility of ND-PRO was shown as three-times higher than ND. Moreover the dissolution testing in pH 6.8 revealed that NDPC released diclofenac totally after the third min, meanwhile ND after 15th. Conclusion: Based on these results, all data supported the formation of a novel NDPC which improve the solubility and dissolution rate of ND.

Key words: sodium diclofenac, L-proline, cocrystal, solubility, dissolution, stability