Effect of Poloxamer on the Dissolution of Felodipine and Preparation of Controlled Release Matrix Tablets Containing Felodipine

The effects of poloxamer and HPMC on the dissolution rate of felodipine were investigated and a felodipine controlled release tablet was developed by increasing the water solubility of felodipine and using swelling polymer to control release rate. Milling of felodipine slightly increased the dissolution rate of felodipine when compared with physical mixture. XRD results indicated that felodipine remained in the crystalline form even after co-milling with poloxamer. Improved dissolution rates after co-milling with HPMC and poloxamer were due to both solubilization effect of polymer and milling. The effect of poloxamer on dissolution rate was more significant than that of HPMC. Based on increased solubility of felodipine in the presence of poloxamer, it was concluded that the improved dissolution rate of felodipine was mainly due to a high local concentration of poloxamer around felodipine. Controlled release felodipine tablets were prepared using poloxamer as a solubilizing agent and $Carbopol^{(R)}$ as a controlled release matrix.