Development and Evaluation of Sustained Release Matrix Tablets of Tramadol Hydrochloride

The objective of the present study was to control the release of freely water soluble Tramadol hydrochloride over a prolonged period of time by embedding the drug into novel wax matrix system. The matrix granules were prepared by melt granulation technique. The need for the administration two to four times a day when larger dose are required can decrease patient compliance. Sustained release formulation that would maintain plasma levels for 24 hrs for once daily dosing of Tramadol hydrochloride was prepared. The compatibility of the drug and wax examined using Differential Scanning Calorimetry (DSC) and Fourier Transform Infrared Spectrophotometer (FTIR). The effect of wax concentration (5 to 35%) and channeling agents (Avicel PH-101 and Di-calcium phosphate) on the in vitro drug release at 24 hrs. was studied. Results of DSC confirmed drug-wax compatibility. Increasing the wax concentration resulted in a significant retardation of drug release. The drug release study revealed that the optimized formulation (F6) 30% novel wax sustained drug release for 24hrs. At the same wax concentration, drug release from tablets decreased with Di-calcium phosphate and increased with Avicel PH 101. Kinetic modeling of in vitro dissolution profiles revealed the drug release mechanism ranges from diffusion controlled or Fickian transport to anomalous type or non-Fickian transport. A hydrophobic matrix system is thus useful technique for prolonging the drug release of freely water soluble drugs such as Tramadol hydrochloride