Solubility and dissolution of physical mixture carbamazepine and amino acids

Objective: The aim of this study was to determine the solubility and dissolution of carbamazepine (CBZ) mixed with an amino acid as a prodrug candidate promoeity compounds CBZ-amino acids, namely glycine (GLY), alanine (ALA), and lysine (LYS). Methods: Physical mixture (PM) of CBZ and amino acids were prepared by mixing CBZ and amino acid equimolar, and then crushed until homogeneous. The content of CBZ in PM determined using UV spectrophotometry at λ 285 nm. PM was evaluated for solubility and dissolution were further characterized by Differential Thermal Analysis (DTA), and Fourier Transform Infrared Spectroscopy (FTIR) spectroscopy. Solubility and dissolution were carrier out in water distilled free CO2 at a temperature 37 ± 0.5 ^oC. Dissolution performed with USP dissolution apparatus II (paddle type) and stirred at a speed of 75 rpm for 60 minutes. Results: Solubility test of carbamazepine and carbamazepine physical mixture of amino acids CBZ-GLY, CBZ-ALA, and CBZ-LYS respectively for 278.62, 258.77, 266.40 and 301.10 mg / mL. The dissolution test results showed % dissolved for 60 min physical mixture (PM) of CBZ-LYS, PM of CBZ-GLY, PM of CBZ-ALA and CBZ alone, respectively for 81.74%, 67.98%, 61.44%, and 56.30%. AUC60 of PM of CBZ-LYS, PM of CBZ-GLY and CBZ-ALA and CBZ alone respectively for 3777.91, 3071.47, 2820.67, and 1743.99. Conclusion: No significant difference between CBZ solubility of PM compared CBZ solubility alone. Based on the statistical test with one-way ANOVA obtained AUC60 of PM of CBZ-LYS > PM of CBZ-GLY = PM of CBZ-ALA > CBZ alone. Physical mixture of CBZ and amino acids significantly improve the dissolution of CBZ. Based on the results of DTA and FTIR CBZ in aqueous media showed that CBZ may have been to transformation form III to dihydrate.