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Author: Admin | 2025-04-28
Illustrated in Figure 2. All spray dried formulations revealed absence of peaks indicating complete amorphization, except for Tad/ alanine/SLS formulation (F11) that showed an emerging small peak corresponding to remaining crystalline domains of SLS and Tad. FIGURE 1 X-ray diffractograms of original Tad, spray dried Tad (F1) and spray dried binary mixtures (F2-F5). FIGURE 2 X-ray diffractograms of spray dried binary and ternary mixtures (F4, F10 and F11) and their pure components. FTIR The IR spectra of the spray dried formulations (F1, F4, F10 and F11) and their pure components are represented in Figure 3. IR spectra of crystalline Tad is characterized by absorption peaks at 3324 cm-1 (N-H stretching of secondary amine), 3091 cm-1 (C-H stretching of aromatic ring), 2904 cm-1(C-H stretching of aliphatic CH3), 1675 cm-1 (C=O stretch of amide), 1645 cm-1 (C=C of aromatic ring), 1435 cm-1 (C-N stretch), 1041 cm-1 (C-O-C stretching) and 744 cm-1 (benzene). Physical mixtures revealed all the characteristic bands without any shift in their spectra compared to individual components (data not shown), demonstrating that there were no interactions between the components in the mixture. However, some of the distinctive peaks were difficult to detect due to overlapping of the peaks of each component in the mixture. Upon spray drying Tad alone, minor variations in its vibrational mode were observed. Such variations were mainly attributed to its molecular rearrangement as a result of its transformation into an amorphous form (Williams et al., 2013). On the other hand, the IR spectrum of Tad/alanine binary mixture (F4) showed a broadening of all bands, a smoothing of the characteristic N-H stretch-peak of Tad and a distortion of the C=O stretch peak of its amide group. Similar findings were also detected in most of FTIR bands of the spray dried ternary mixtures (F10 and F11). However, no
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