| Tramadol is chemically centrally acting synthetic analgesic. Its commercial controlled release product is available in three different strengths, 100 mg, 200 mg and 300 mg. The controlled release formulation (UltramRTM ER) has several potential advantages over conventional dosage forms, such as patient compliance by reducing the frequency of dosage, minimizing number of side effects, reducing the strength of the required dose while increasing the effectiveness of the drug. The controlled release formulation provides a uniform and prolonged therapeutic effect.;Currently, there are lots of drug substances marketed with varied chemical, physical and pharmacokinetic properties. Various techniques have been used to formulate controlled release dosage forms. Solid dispersion system has been used widely to increase the dissolution rate and bioavailability of water insoluble drugs. In this decade, the solid dispersion technology is gaining interest for different purposes like, sustained release of drugs, enhance release of drugs, improved solubility and stabilulity.;The main objective of the study was to explore the applications of solid dispersion technique to simplify the art of sustaining the drug release from solid dosage forms. Solid dispersions were prepared using different ratios of drug and rate controlling polymers, by solvent evaporation method. The dissolution profiles of solid dispersion formulations were determined by the USP I rotating basket method. Among all the formulations evaluated, the solid dispersion formulation containing drug: hydroxypropyle cellulose: campritol ATO 888 with weight ratio 1:1:2 gave the desired controlled release in-vitro dissolution profile over 24 hours. To prove that, the drug release is controlled by the solid dispersion formulation, the dissolution profiles of optimized solid dispersion formulation and physical mixture of the same formulation were compared. The result justified that the formation of solid dispersion sustained the drug release over extended period of time, not the presence of rate controlling polymers in the formulation.;As the main objective of this study was to evaluate the feasibility of solid dispersions to produce products of varied strengths using the same single formulation, the optimized solid dispersion formulations equivalent to 50 mg, 100 mg, 200 mg and 300 mg were tested for their in-vitro dissolution profiles. The graphical presentation revealed that the percentage drug release and the release pattern were similar regardless of the dosage strength. This supports the fact that a single solid dispersion powder enables one to conveniently develop the multiple strength dosage forms in this drug.;Furthermore, the solid dispersion powder was evaluated for physical characteristics using Differential Scanning Calorimetric, X-ray diffraction and Fourier Transform Infrared spectroscopy. These studies supported the drug exists in the amorphous form and there are no chemical interaction among the drug and polymeric materials. |
