Tropical Journal of Pharmaceutical Research
Pharmacotherapy Group, Faculty of Pharmacy, University of Benin, Benin City, Nigeria
Vol. 14, No. 11, 2015, pp. 1953-1960
Bioline Code: pr15255
Full paper language: English
Document type: Research Article
Document available free of charge
Tropical Journal of Pharmaceutical Research, Vol. 14, No. 11, 2015, pp. 1953-1960
© Copyright 2015 - Tropical Journal of Pharmaceutical Research
Process and Kinetic Mechanism of Elimination of Chlorine Combined in Molecule of Bleached Shellac|
Liao, Yalong; Zhou, Juan & Huang, Feirong
Purpose: To investigate the process and kinetics of the removal of chlorine integrated in a molecule of
bleached shellac applied as pharmaceutical excipient.
Methods: Sodium ethoxide was employed to react selectively with the carbon atom connecting with
chlorine, which induced the removal of chlorine by means of elimination reaction. The technologic
parameters, such as dosage of sodium ethoxide, temperature, time, etc, influencing dechlorination
efficiency were studied. Furthermore, the kinetics of chlorine removal was investigated by analyzing the
variation of chlorine content with time and temperature.
Results: The results demonstrate that the optimal conditions for eliminating combined chlorine are to
react with 3.15 g of sodium ethoxide at 90 oC for 90 min. Under the optimal conditions, the content of
chlorine in the final products is 0.28 % w/w, which is far smaller than that in the products prepared
without dechlorination (2.6 % w/w)..
Conclusion: Combined chlorine, which is harmful to the properties of shellac, can be removed in the
presence of sodium ethoxide by means of elimination, and the reaction for chlorine content of shellac is
first order reaction.
Enteric coating; Sustained release; Elimination method; Nucleophile; Shellac; Natural products
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