Pharmaceutical applications solid dosage formulations

The next development in NIR spectroscopic analysis of pharmaceuticals was the analysis of solid dosage formulations. This represented a significant advance in pharmaceutical analysis, because it increased the potential for the application of the method to a large number of pharmaceutical processes. NIR was no longer restricted to the analytical laboratory rather, it could now be used on the production floor. In addition, it obviated the need for extraction with solvents like chloroform and carbon tetrachloride prior to NIR analysis. This technique has been used in the NIR analysis of blends, granules, encapsulation matrices, and milled tablets. 

In contrast to solution-phase or direct polarization solid-state NMR experiments, CP-MAS is not a truly quantitative technique. As a result of the cross-polarization step, the integral intensities of peaks in CP-MAS spectra do not directly reflect the stoichiometry of nuclei in the molecule. CP-MAS signals originate from protons, and its transfer efficiency varies from carbon to carbon, based on proximity of protons and local mobility of the molecule. In most pharmaceutical applications, only relative concentrations of mixtures of two or more polymorphs need to be determined even in complex dosage forms. The absolute concentration of the drug in formulation is usually known or can be determined by other techniques. 

Chiou and Riegelman reviewed the pharmaceutical applications of solid dispersion systems. These authors found complete and rapid absorption of griseofulvin dispersed in polyethylene glycol 6000 for both capsule and tablet dosage forms, in contrast to irregular and incomplete absorption from commercially available micronized drug. Munzel reviewed various formulation variables which can influence drug action. Kakemi and co-workers studied the effects of buffer components, osmotic... 

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