Theophylline release kinetics

TABLE 1 Theophylline Release Rates from Asymmetric-Membrane Tablet Coatings, Results of Fitting Release Profiles to Zero-Order Kinetics, and Precipitation Times Determined from Model Predictions... 

Benita, S. Donbrow, M. Release kinetics of sparingly soluble drags from ethylcellulose walled microcapsules. Theophylline microcapsules. J. Pharm. Pharmacol. 1982, 34,547-551. 

On the other hand, Siepmann and coworkers [132] focus the attention on release kinetics from aqueous coating technique. In particular, theophylline pellets (wSOO pm diameter Boehringer Ingelheim, Ingelheim, Germany) coated by two different kinds of water-insoluble and enteric polymer ((1) EC [Aquacoat ECD, EMC do Interorgana, Koln,... 

L. Hendeles, R. Iafrate, and M. Weinberger, A clinical and pharmacokinetic basis for the selection and use of slow release theophylline products, Clin. Pharmaco-kinet, 9, 95 (1984). 

Lavasanifar, A., Ghalandari, R., Ataei, Z., Zolfaghari, M.E. and Mortazavi, S.A. (1997) Microencapsulation of theophylline using ethylcellulose in vitro drug release and kinetic modelling. Journal of Microencapsulation, 14, 91-100. 

NoreU MC, Andersson HS, Nicholls lA. Theophylline molecularly imprinted polymer dissociation kinetics a novel sustained release drug dosage mechanism. J Mol Recognit 1998 11 98-102. 

Lavasanifar A, Ghalandari R, Atari Z, ZoUaghari ME, and Mortazavi SA. 1997, Microencapsulation of theophylline using ethilcellu-lose In vitro drug release and kinetic modelhng. J. Microencapsulation 1997 14 91-100. 

Katime, L Novoa, R. Zuluaga, F. Swelling kinetics and release studies of theophylline and aminophylline from acrylic acid/n-alkyl methacrylate hydrogels. Eur. Polym. J. 2001, 37, 1465-1471. 

When the occurrence of flip-flop kinetics is not recognised it may compromise the interpretation of results from studies on the pharmacokinetic behaviour of slow release dosage forms. Flip-flop pharmacokinetics may occur with any extravascularly administered parenteral slow release dosage form. Intramuscular depot injectimis of antipsychotics such as fluphenazine decanoate, haloperidol decanoate or flupenthixol decanoate show this behaviour. It also occurs after the administration of oral slow release products of active substances such as isoxuptine, carbamazepine, diclofenac, valproic acid, morphine and theophylline. 

M.G. Norell, H.S. Andersson, LA. Nicholls, Theophylline molecularly imprinted polymer dissociation kinetics A novel mechanism sustained release drug dosage, /Mol Recognit, 11, 98-102, 1998. 

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