Controlled Release Solid Dispersion of Niacin for Direct Use in the Preparation of Multiple Strengths Solid Dosage Forms

Controlled release formulations have been traditionally prepared using complicated methods like solid matrices, osmotic pumps and other sophisticated systems. However, the use of these techniques in the manufacturing of controlled release dosage forms involves use of sophisticated methods and equipment. To simplify the procedure to make such dosage forms, the use of solid dispersion method was investigated. This study was undertaken to develop a single controlled release solid dispersion powder for its direct use in the manufacture of 250mg, 500mg and 750 mg tablets dosage forms of Niacin.;Solid dispersion formulations were developed using solvent evaporation method. Various samples were prepared using different drug to polymer ratios in anhydrous ethanol solution. The drug-polymer solution was evaporated to dryness while stirring under a gentle stream of nitrogen at 41°C. The sample residue was further dried overnight in an oven at 41°C and screened to obtain powder. Using the appropriate amounts of powder, sample tablets were compacted to contain 250mg, 500mg and 750mg of drug respectively. In-vitro dissolution studies were carried out for 24 hours period using the United States Pharmacopoeia dissolution apparatus I method. A commercially marketed product, NiaspanRTM was used as a control for comparison purposes.;The dispersion sample containing drug/HPC at the weight ratio of 5:1 gave the optimum in-vitro controlled release profiles from all tablet strengths evaluated, and these were found to be similar to the control. The data revealed that the percentage drug release and drug release patterns were same regardless of the dosage strength suggesting that the dispersion powder was capable of controlling the drug release. In addition, the preliminary evaluation of the physical characteristics of the formulation powder via X-ray diffraction and Differential Scanning Calorimetric studies supports that there are no chemical interactions within the formulation ingredients.;A single solid dispersion of Niacin containing Drug/HPC at a weight ratio of 5:1 provided a suitable drug powder for its direct use in the product development of multiple strengths tablet dosage forms. Moreover, the amount of rate-controlling polymer is 50% less than the amount present in the control product. Using this simple formulation approach, it is possible to minimize the expenses and formulation work associated with the development of individual multiple strength dosage forms of this clinically important drug.