Most pharmaceutical drugs face several obstacles before reaching the site of action and delivering the desired therapeutic effect. To overcome these challenges, several drug delivery systems have been designed and tested.
In particular, controlled-drug release systems are effective in maintaining the desired physiological drug concentration within the body. Chitosan and its derivatives are being used for this purpose. The performance of chitosans in this application is dependent on its molecular characteristics which can be measured by SEC/GPC.
Chitosan dissolution is often problematic; however an aqueous SEC/GPC method was developed herein to measure absolute Mw, IV, and Rh of was measured (Table 1).
In this example, two pharmaceutical grades of chitosans, A and B, were analyzed and compared by advanced-detection SEC:
Figure 1. Overlay chromatogram obtained from the RI detector of Chitosan Grades A (black) and B (green).
Advanced SEC/GPC analysis was successfully employed to detect molecular variations between different pharmaceutical grades of chitosan and differentiate sources.