Quantitative Analysis of Crystalline Materials in Binary Compacts Using Time Domain Spectra of THz Spectroscopy and Density Dependence

Polymorph and pseudo-polymorph systems play a major role in the pharmaceutical industry because of their potential to impact the performance of finished dosage forms. Quantitative analysis of polymorph and pseudo-polymorph is becoming increasingly important for solid oral dosage forms and transdermal products. A rapid, non-destructive analytical tool is required to reduce the time and cost for quantitative analysis. Terahertz Time Domain Spectra has emerged as a potential analytical tool for rapid and non-destructive analysis of these systems. Terahertz Time Domain Spectra provides high specificity for polymorphic study due to the ability to probe inter-molecular and phonon lattice vibration directly into the crystal structure.  

The feasibility of Terahertz Time Domain Spectra for quantitative analysis of anhydrous theophylline and the monohydrate in compacts was studied. This study included the analysis of density dependence in quantification accuracy. The effect of density on the Terahertz Time Domain Spectra was demonstrated. An improvement in model performance was demonstrated when density was undertaken into consideration.