Abstract: Carvedilol is a non-specific β-adrenergic blocker with α-blocking activity. It is a basic drug and exhibits pH dependent solubility. In the present study, the influence of nature and concentration of selected superdisintegrants and lubricants on the dissolution behavior of carvedilol was evaluated. Tablets were made by direct compression and were compressed to equal hardness. Dissolution kinetics of all the formulations were determined. Due to variation in the physico-chemical properties of the superdisintegrants and lubricants, variation was observed in the dissolution rate of the drug from tablet to tablet. Sodium starch glycolate at 7% w/w concentration significantly improved the dissolution rate of carvedilol when compared with the other superdisintegrants studied. Among the three lubricants used, magnesium stearate at 1.5% w/w concentration showed rapid drug release.

 
Introduction: More than 60% of new drugs currently under development today are considered poorly soluble. To achieve maximum therapeutic efficacy, selection of formulation ingredients that enhance the dissolution of poorly soluble drugs has become increasingly important. A drug’s dissolution rate and extent of release from solid dosage forms is determined by the solubility properties of the drug alone or in combination with that of the formulation ingredients. The ultimate dissolution characteristics of the formulation of a poorly soluble drug are determined mainly by other ingredients like superdisintegrants and lubricants1.
Superdisintegrants are now frequently used in tablet formulations to improve the rate and extent of tablet disintegration and thus improve the rate of drug dissolution. Commonly used superdisintegrants such as crospovidone, croscarmellose sodium, and sodium starch glycolate are highly efficient at low concentration levels (2–5% w/w). The choice of superdisintegrant for a tablet formulation depends largely on the nature of the drug being used. Water-soluble materials tend to dissolve rather than disintegrate, while insoluble materials generally tend to disintegrate if an appropriate amount of disintegrant is included in the formulation. The correlation between tablet disintegration and drug dissolution, however, is not always observable2.