Abstract
Quality evaluation methods for Transdermal Drug Delivery System (TDDS) pharmaceutical with crystal reservoir system using microscopic Raman, near infrared and terahertz spectroscopy and imaging technique, were developed. The crystal reservoir system that contains an active substance as crystalline form is one of useful release-rate controlling systems for active substances which have high skin-penetration such as tulobuterol (TBR). The conversion of TBR from crystalline form to non-crystalline form in a matrix has important role for a release-rate control. Therefore, crystallization of TBR in a matrix is one of the critical quality factors of this type of TDDS tapes. However, confirmation and/or detection of crystalline TBR in a matrix would be difficult because visual test methods such as a microscopy could not apply through an opaque liner and a supporting board. In this case, non-destructive and high penetrate-able spectroscopic imaging methods would be useful for analyzing it. The authors examined applicability of microscopic spectroscopic imaging methods using laser Raman, near-infrared and terahertz electro-magnetic waves as quality analytical tools for confirming of crystalline TBR in the model tapes and the commercial tapes.