3.5.3 X-Ray Diffractometery (XRD)

3.5.3 X-Ray Diffractometery (XRD).
The crystallinities of pure Zolmitriptan, excipients and liquisolid system were evaluated by XRD measurement. It has been seen that polymorphic changes of the drug are important factors, which may affect the drug dissolution rate and bioavailability(135). The X- ray diffractogram of pure Zolmitriptan Figure (25) exhibited several sharp peaks at different angle (2Ɵ),the three strongest angles were 19.2 Ɵ, 21.9 Ɵ and 23.8 Ɵ ,other angles were 12.2 Ɵ,13.7 Ɵ, 14.2 Ɵ,15.4 Ɵ, 25.5 Ɵ, and 28.8 Ɵ suggested that the drug existed as crystalline material(136).Zolmitriptan characteristic peaks were observed in the physical mixture as shown in Figure (27) demonstrating that its crystalline structure remained unchanged during the physical blend. On the other hand, the liquisolid (F18) powder X-ray diffraction pattern Figure (28) showed only one sharp diffraction peak at 2Ɵ angle of 22.3 belonging to carreier Avicel (PH-102) Figure (26), indicating that only Avicel (PH-102)
Such absence of Zolmitriptan constructive reflections (specific peaks) in the liquisolid X-ray diffractogram indicates that drug has almost entirely converted from crystalline to amorphous or solubilized state, such lack of crystallinity in the liquisolid system indicates that Zolmitriptan was