Analysis of mean disintegration time and mean dissolution time by moment analysis using microcalorimetric curves

The mean disintegration time (MDGT; mean time required for disintegration of tablets) and mean dissolution time (MDST; mean time required for drug dissolution) of water-soluble drugs from solid dosage forms were determined by moment analysis using microcalorimetric curves. Microcalorimetric curves for heat of dilution and for heat of dissolution of the drug were prepared, and the zeroth and first moments of the calorimetric curves were then calculated. The difference between the first moments of the curves for powder dissolution and tablet dissolution was taken to be the MDGT. The difference between the first moment of the curve for heat of dilution and that of the curve for heat of dissolution was taken to be the MDST. Nicotinic acid and D-mannitol were used as model drugs. The dissolution rate was determined by the conventional beaker method and also by the deconvolution method. The dissolution process could be traced well by moment analysis, as well as by the other methods employed. Moment analysis has some advantages: (a) both the MDGT and the MDST can be determined simultaneously; (b) it is applicable to many drugs that are soluble with heat evolution without the need for quantitative analysis of the drug.