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Authors
Affiliations
1 Department of Pharmaceutics, College of Pharmacy and Health Sciences, Ajman University of Science and Technology, AE
2 Department of Pharmaceutical Chemistry, College of Pharmacy and Health Sciences, Ajman University of Science and Technology, AE
Source
Research Journal of Pharmaceutical Dosage Form and Technology, Vol 7, No 1 (2015), Pagination: 1-6
Abstract
The influence of khat on both in-vitro and in-vivo availability of tetracycline-HCl has been evaluated. The in-vitro availability data have reflected a statistically significant interaction between khat extract and tetracycline-HCl in two buffer solutions simulating intestinal and gastric media (phosphate buffer-pH 7 and 0.1 HCl-pH 1.2 respectively). In the in-vivo availability studies, ten adult healthy Yemeni volunteers participated. The obtained in-vivo availability data indicated a statistically significant reduction in most pharmacokinetics parameters. A statistically significant % reduction in the maximum plasma tetracycline-HCl concentration (Cmax) and absorption rate constant (Ka) as well as a significant enhancement of time to reach the peak plasma concentration (Tmax), were observed as a result of taking tetracycline-HCl just before khat chewing (trial B) and more pronounce during khat chewing (trial D) compared to the control (trial C). In addition a statistically significant % reduction in area under curve (AUC0→∞) has been observed reflecting a reduction in the extent of in-vivo tetracycline-HCl availability as a result of khat chewing. Statistically significant % reductions in the biologic half-life (t½) and elimination rate constant (Kel) were also observed.The reduction in tetracycline-HCl concentration when mixed with khat extract, as shown by in-vitro data, may reflect a possible formation of tetracycline-HCl complexes with one or more of khat constituents. The reduction in the rate and extent of in-vivo tetracycline-HCl availability as a result of khat chewing, may be due to the possible formation of non-absorbable tetracycline-HCl complexes with one or more of khat constituents or possible delaying of gastric emptying induced by khat that may prolong the resident time of tetracycline-HCl in the stomach leading to its possible degradation into the less antimicrobial active form epitetracycline.
Keywords
Availability, Pharmacokinetics Parameters, Tetracycline-HCl, Khat.
