TY - JOUR
T1 - Crystalline properties of carbamazepine in sustained release hydrophilic matrix tablets based on hydroxypropyl methylcellulose
AU - Katzhendler, Ifat
AU - Azoury, Reuven
AU - Friedman, Michael
PY - 1998/6/1
Y1 - 1998/6/1
N2 - The influence of hydroxypropyl methylcellulose (HPMC) on the crystal habit properties of carbamazepine in sustained release matrix tablets and in aqueous solutions was investigated using differential scanning calorimetry (DSC), X-ray powder diffraction and scanning electron microscopy (SEM). The results suggest that HPMC inhibits the transformation of carbamazepine to carbamazepine dihydrate in the gel layer of hydrated tablets and in aqueous solutions (depending on HPMC concentration), participates in its crystallization process and induces amorphism of carbamazepine crystals. The mechanism which explains these effects envisages the polymer serving as a template or microsubstrate for nucleation in the crystallization process. We assume that the interaction between the drug and polymer occurs by hydrogen bonding. The hydroxyl groups of the polymer may attach to the drug at the site of water binding, and thus its transformation to the dihydrate form, is inhibited. A more specific interaction involves structural matching (similar bond spacing distances) between inter-atomic distances in the crystal lattice of carbamazepine dimer and intra-atomic distances along the polymer chain.
AB - The influence of hydroxypropyl methylcellulose (HPMC) on the crystal habit properties of carbamazepine in sustained release matrix tablets and in aqueous solutions was investigated using differential scanning calorimetry (DSC), X-ray powder diffraction and scanning electron microscopy (SEM). The results suggest that HPMC inhibits the transformation of carbamazepine to carbamazepine dihydrate in the gel layer of hydrated tablets and in aqueous solutions (depending on HPMC concentration), participates in its crystallization process and induces amorphism of carbamazepine crystals. The mechanism which explains these effects envisages the polymer serving as a template or microsubstrate for nucleation in the crystallization process. We assume that the interaction between the drug and polymer occurs by hydrogen bonding. The hydroxyl groups of the polymer may attach to the drug at the site of water binding, and thus its transformation to the dihydrate form, is inhibited. A more specific interaction involves structural matching (similar bond spacing distances) between inter-atomic distances in the crystal lattice of carbamazepine dimer and intra-atomic distances along the polymer chain.
KW - Carbamazepine
KW - Crystallinity
KW - Differential scanning calorimetry
KW - Hydroxypropyl methylcellulose
KW - Scanning electron microscopy
KW - Sustained release
KW - X-ray diffraction
UR - http://www.scopus.com/inward/record.url?scp=0031750464&partnerID=8YFLogxK
U2 - 10.1016/S0168-3659(98)00002-9
DO - 10.1016/S0168-3659(98)00002-9
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C2 - 9741905
AN - SCOPUS:0031750464
SN - 0168-3659
VL - 54
SP - 69
EP - 85
JO - Journal of Controlled Release
JF - Journal of Controlled Release
IS - 1
ER -