Ronald J. Sawchuk, PhD
PhD in Pharmaceutical Chemistry and Pharmacokinetics, University of California, San Francisco
MSc in Pharmaceutics, University of Toronto
BSc in Pharmacy, University of Toronto
Dr. Sawchuk's research focuses on basic and applied pharmacokinetics. A significant part of this activity has dealt with absorption and elimination of anticonvulsants in human and animal studies. Clinical studies have been directed toward optimizing therapeutic response by using pharmacokinetics to individualize dosing regimens. A number of anticonvulsants that demonstrate nonlinear (time-dependent and/or concentration-dependent) pharmacokinetics have been the subject of this research.
A major research focus in Dr. Sawchuk's group is the investigation of drug delivery to the middle ear. One goal of this work is to enhance distribution of antibiotics in the treatment of otitis media. His group is also examining the distribution of anti-infective drugs to lung tissue. Other research activities involve the targeting of centrally acting agents to brain tissue. These investigations employ microdialysis coupled to online HPLC in freely moving, conscious animals to continuously monitor the concentration of drug and/or metabolites in tissue extracellular space.
Because of the reliance of pharmacokinetic studies on availability of sensitive and specific methods for analysis of drugs in biological fluids, significant time and effort is devoted to development of analytical methods. The emphasis here is on HPLC and LC/MS/MS. Dr. Sawchuk directs the Bioanalytic and Pharmacokinetic Services Laboratory. This laboratory interacts with the pharmaceutical industry in the conduct of preclinical and clinical studies on new chemical entities and existing drugs.
- C. Dahyot-Fizelier, S. Lefeuvre, L. Laksiri, S. Marchand, R.J. Sawchuk, W. Couet and O. Mimoz. Kinetics of imipenem distribution into the peritoneal fluid of patients with severe peritonitis studied by microdialysis. Clin. Pharmacokinetics 49(5): 323-334 (2010).
- R.J. Sawchuk. Liquid-chromatographic determination of cyclosporin A in blood and plasma. Citation Classic. Clin. Chem. 54: 2076-2077 (2008).
- D.P. Scher, R.J. Sawchuk, B.H. Alexander, and J.L. Adgate. Estimating absorbed dose of pesticides in a field setting using biomonitoring data and pharmacokinetic models. J. Toxicol. Environ. Health A. 71(6): 373-83 (2008).
- J. Karjagin, S. Lefeuvre, K. Oselin, K. Kipper, S. Marchand, A. Tikkerberi, J. Starkopf, W. Couet and R.J. Sawchuk. Pharmacokinetics of meropenem determined by microdialysis in the peritoneal fluid of patients with severe peritonitis associated with septic shock. Clin. Pharmacol. Ther. 83(3): 452-459 (2008).
- Y. Huang, Z. Yang, L. Cartier, B. Cheung, and R.J. Sawchuk. Estimating amoxicillin influx/efflux in chinchilla middle ear fluid and simultaneous measurement of antibacterial effect. Antimicrobial Agents and Chemotherapy 51(12): 4336-4341 (2007).
- R.J. Sawchuk and B.W.Y. Cheung. Application of microdialysis in pharmacokinetic studies, in Handbook of Microdialysis: Methods, Applications and Clinical Aspects, B.H.C. Westerink and T.I.F.H. Cremers (editors), Academic Press, Amsterdam, 2007, pp. 601-622.
- Z. Yang, P. Manitpisitkul and R. J. Sawchuk. In situ studies of regional absorption of lobucavir and ganciclovir from rabbit intestine and predictions of dose-limited absorption and associated variability in humans. J. Pharm. Sci. 95: 2276-2292 (2006).
- B.W.Y. Cheung, L.L. Cartier, H.Q. Russlie and R.J. Sawchuk. The application of sample pooling methods for determining AUC, AUMC and mean residence times in pharmacokinetic studies. Fundamental & Clinical Pharmacology 19: 347-354 (2005).
- Z.Yang, Y. Huang, G. Gan and R. J. Sawchuk. Microdialysis evaluation of the brain distribution of stavudine following intranasal and intravenous administration to rats. J. Pharm. Sci. 94: 1577-88 (2005).
- J.Z. Peng, R.P. Remmel and R.J. Sawchuk. Inhibition of murine cytochrome P4501A by tacrine: in vitro studies. Drug Metab. Dispos. 32: 805-812 (2004).
- T. Zhu, B.W.Y. Cheung, L.L. Cartier, G.S. Giebink and R.J. Sawchuk. Simultaneous intravenous and intramiddle-ear dosing to determine cefditoren influx and efflux clearances in middle ear fluid in freely moving chinchillas. J. Pharm. Sci. 92: 1947-1956 (2003).