Heating and chemical denaturation of egg albumin matrix and its effect on the release kinetics of theophylline from tablets
2004
Shaheen, S.M. | Rashid, M. (Rajshahi Univ. (Bangladesh). Dept. of Pharmacy) | Anwar-ul-Islam, M. | Reza-ul-ul-Jalil
Egg albumin (EA) matrix tablets containing theophylline (TH) were prepared by direct compression using 13 mm die and punch and a hydraulic press (3 ton compressor) after simple dry mixing of these two ingredients. Chemical denaturation of EA using both glutaraldehyde and formaldehyde as cross linking agents showed a remarkable decrease in TH release rate from matrix tablets when compared with untreated and heat denatured TH matrix tablets. The release rate was further reduced when mutual chemical and heating denaturation were applied. In all cases release mechanism was square root of time dependent indicating diffusion type release. It was found that heating for 1 h at only 65 degree C was enough to produce the release retardation effect, whereas, heating beyond 65 degree C (up to 105 degree C) had no significant effect on the release rate. Heat denatured tablets also showed a Higuchian release pattern. The release rate of heat denatured (at 105 degree C for 1 h) matrices were slightly decreased than the unheated tablets. However the duration of heating (20 to 100 min) had no significant effect on the release rate.
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