Progress 07/01/06 to 06/30/08
Outputs
OUTPUTS: The duration of effect of a single dose of grapefruit juice on the pharmacokinetics of several drugs has been studied extensively. However, data concerning the effect of grapefruit juice on the pharmacokinetics of CYP3A4 substrates after repeated use are limited. Simvastatin, lovastatin and atorvastatin have HMG-CoA reductase inhibitory activity that results in reductions in cholesterol biosynthesis. Right now there is only one case report of a woman developing severe muscle damage from simvastatin (80 mg/day) after she began eating one grapefruit per day. Although there have been no systematic investigations of a grapefruit-simvastatin interaction regarding the duration of consumption, to be on the safe side, patients taking simvastatin are advised now not to eat grapefruit or drink grapefruit juice. The purpose of the study was to assess the magnitude to which GFJ changes the simvastatin (SV) plasma levels after long term use in the rat model and to assess the possibility of adaptive processes. Non-fasted male Sprague-Dawley rats weighing 239-346 g were used. On the first day of the experiment the rats were dosed with their respective simvastatin dose (SVlowdose = 20 mg/kgxday-1 (SV20) Simvastatin, SVhighdose = 80 mg/kgxday-1 (SV80) Simvastatin) and their grapefruit juice permutations (simvastatin and regular strength grapefruit juice; SV20RS and SV80RS, and simvastatin and double strength grapefruit jucie; SV20DS and SV80DS). To establish a pharmacokinetic baseline profile, blood samples (500 ul) were taken from the sublingual vein at 0, 1, 2, 4, 6, 8, 12 hours after drug administration (three blood collections per day; e.g. time points 1, 4, 8; then two weeks washout, then the remaining time points 0, 2, 6, 12 in the same animals). After the acute phase two blood samples 1000 ul was taken each week for 4 weeks right before dosing the drug (trough level) and 2 hours after dosing (peak level). The blood samples were analyzed by HPLC-MS for Simvastatin, Simvastatin acid. Grapefruit juice did not have a significant effect on the pharmacokinetic parameter of either Simvastatin lactone or its hydroxy acid form when administered as 20 mg/kg over 28 days. There were no significant differences in either regular strength or double strength grapefruit juice group. RS and DS GFJ significantly increased the exposure of a 80 mg/kg simvastatin lactone during the first administration by 1.3 fold. The main active metabolite exposure increased by 1.3 fold. During the chronic treatment with RS GFJ the Cmax of SV on day 7 and day 28 increased by around 1.8 fold and 1.7 fold for the hydroxy acid. Cmax of SV increased maximally by 2- fold on day 28 and 2.1 fold on day 14 for SVA. As hypothesized, Grapefruit juice in either concentration (DS or RS) administered daily did not seem to have a relevant effect on the pharmacokinetics on a low acute or chronic dose of simvastatin. When administered with a high dose of simvastatin however, concentrations were elevated up to the last day of the study. Concentrations of the main active metabolite were also elevated up to the end of the study. It seems that the interaction persist over the full range of the study. PARTICIPANTS: Individuals: Veronika Butterweck, PhD, Principal Investigator, (25% effort) is Assistant Professor of Pharmaceutics at the College of Pharmacy, University of Florida. As principal investigator, she was responsible for coordination and execution of all aspects of the research. She did oversee all animals experiments. She did ensure that adequate progress was made in assay execution. She communicated regularly with all co-investigators and personnel to facilitate accomplishment of all specific aims. Along with the other investigators, Dr. Butterweck was involved in data analysis, interpretation, and publication to meet the specific aims herein. Finally, Dr. Butterweck worked to stimulate collaboration between her group and other investigators outside of the current proposal. Hartmut Derendorf, Ph.D., Co-investigator, (25% effort) is Distinguished Professor and Chair of the Department of Pharmaceutics. As Co-investigator, he was responsible for coordination and execution of the PK studies. He was responsible for analysis of data regarding simvastatin and simvastatin acid plasma levels, and also executed PK analysis of different grapefruit juices used in the study. He is also involved in data management, interpretation, and manuscript preparation. Jie Wang, Ph.D., (12 cal months) is a Postdoctoral fellow in Dr. Butterweck's laboratory. Her expertise is in LC/MS/MS analysis of molecules of interest. She was responsible for quantifying simvastatin and its metabolites in the plasma of all animals and for all aspects involving cell culture studies. She was also involved in preparation of data outputs for analyses, interpretation, and scientific dissemination. Susanne Mertens-Talcott, Ph.D., (12 cal months) worked as a Postdoctoral fellow on this project. She contributed to the in-vitro investigations of components of grapefruit juice and their effect on drug absorption, and prepared abstracts and publications. Immo Zdrojewski, Ph.D., Graduate Student, (12 cal months). He assisted in all aspects of the study including animal studies, cell culture, PK analyses, and clinical execution of the protocol. He has executed the simvastatin-GFJ animal studies and was responsible for data analysis, preparation of abstracts, and manuscripts. Whocely Victor de Castro, Ph.D., Graduate Student (12 cal months). He performed analysis of a variety of commercially available grapefruit juices to study the variability of the ingredients. Furthermore, he established the in-vitro cell culture system to study the effect of grapefruit juice components on drug absorption. Partner Organizations: Florida Departement of Citrus (William Stinson, Ph.D.); USDA/ARS Citrus & Subtropical Products Laboratory, Winter Haven (John Manthey, Ph.D.) Collaborators and contacts: David Greenblatt, MD (Tufts University, Boston); Lawrence Lesko, Ph.D. (FDA) Training or professional development: The work on this project contributed to two Ph.D. dissertations. Furthermore, many other graduate students in the Department of Pharmaceutics interacted in numerous group meetings and seminars. TARGET AUDIENCES: Target audiences: Health Care Providers (Physicians, Pharmacists, Nurses), Patients (Including population groups such as racial and ethnic minorities and those who are socially, economically, or educationally disadvantaged), Pharmaceutical Industry, Food&Drug Administration, other Academic Institutionas and Research Organizations Efforts: Establishment of a Food and Drug Interaction Website (www.druginteractioncenter.org)to provide access to clinically relevant grapefruit juice-drug interaction information for both patients and health care providers. Seminars, Presentations at national and international conferences. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
During the last years, many reports about interactions between various drugs and grapefruit juice have been published. It has become clear that several different mechanisms are involved in these interactions involving both drug metabolism and drug transporter systems. It is of critical importance to fully understand these mechanisms in order to manage and avoid these potential interactions. The research in this project contributes to a better understanding of these interaction mechanisms. It will allow developing a rational approach to evaluate magnitude and relevance of the interaction and make recommendations for specific drugs. For example, for some drugs it has been shown that a grapefruit-juice induced elevation of drug concentrations is not of clinical consequence and hence insignificant. For other drugs, where the interaction with grapefruit juice may be of clinical concern, alternative drugs from the same class may be recommended which provide the same therapeutic benefit but do not interact significantly with grapefruit juice. Regular strength GFJ did not alter the exposure of the low dose of simvastatin and only minimally altered the exposure of the high dose of simvastatin. This is even more interesting considering that we chose a dosing scheme that would reflect a real life situation rather than an artificial overexposure to large quantities of grapefruit juice. The animals were dosed with 5mL/kg juice, which would be equivalent to a regular 8oz glass of RS GFJ or two 8oz glasses when we dosed with DS GFJ. Previous studies have shown that pre-dosing TID with DS or RS GFJ can significantly alter the plasma concentrations in humans. Clear difference however can be seen in the extent to which these plasma concentrations are altered. The fact that large quantities of grapefruit juice can alter the pharmacokinetics of simvastatin has also been recognized by the regulatory authorities and is reflected in the labeling of the drug. In conclusion, this is the first study were a chronic effect of simultaneous administration of drug and grapefruit juice has been investigated. Our results indicate that there is no significant difference between plasma concentration with or without grapefruit juice consumption.
Publications
- Polymethoxylated flavones and other phenolic derivates from citrus in their inhibitory effects on P-glycoprotein-mediated transport of talinolol in Caco-2 cells. MERTENS-TALCOTT, S., DE CASTRO, W.V., MANTHEY, J.A., DERENDORF, H., BUTTERWECK, V. J Agric Food Chem. 55(7):2563-8 (2007)
- Grapefruit juice-drug interactions: Grapefruit juice and its components inhibit P-glycoprotein (ABCB1) mediated transport of talinolol in Caco-2 cells. DE CASTRO, W.V., MERTENS-TALCOTT, S., DERENDORF, H., BUTTERWECK, V.; J Pharm Sci 96 (10): 2808 - 17 (2007)
- Potential of pharmacokinetic profiling for detecting herbal interactions with drugs. BUTTERWECK, V., DERENDORF, H., Clin Pharmacokinet. 2008;47(6):383-97
- Effect of Grapefruit Juice, Naringin, Naringenin, and Bergamottin on the Intestinal Carrier-Mediated Transport of Talinolol in Rats. DE CASTRO, W.V., MERTENS-TALCOTT, S., DERENDORF, H., BUTTERWECK, V.; J Agric Food Chem. 56(12):4840-5 (2008)
- Evaluation of Grapefruit Juice and its components on P-glycoprotein activity. BUTTERWECK, V., DE CASTRO, W.V., DERENDORF, H.; Lecture: Experimental Biology Annual Meeting, section: PHENRIG, Washington DC, USA, April 28th-May 2nd, 2007
- Exploring mechanisms of grapefruit juice drug interactions and its potential toxicity. BUTTERWECK, V., ZDROJEWSKI, I., DE CASTRO, W.V., DERENDORF, H.; Keynote Lecture: 55th Annual Meeting of the Society of Medicinal Plant Research, Graz, Austria; September 1st-6th, 2007
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Progress 07/01/06 to 06/30/07
Outputs
The duration of effect of a single dose of grapefruit juice on the pharmacokinetics of several drugs has been studied extensively. However, data concerning the effect of grapefruit juice on the pharmacokinetics of CYP3A4 substrates after repeated use are limited. Simvastatin, lovastatin and atorvastatin have HMG-CoA reductase inhibitory activity that results in reductions in cholesterol biosynthesis. Rhabdomyolysis (muscle toxicity) is known as a rare but severe adverse effect of these agents. Right now there is only one case report of a woman developing severe muscle damage from simvastatin (80 mg/day) after she began eating one grapefruit per day. Although there have been no systematic investigations of a grapefruit-simvastatin interaction regarding the duration of consumption, to be on the safe side, patients taking simvastatin are advised now not to eat grapefruit or drink grapefruit juice. The purpose of this study was to determine in vivo the effect of different
concentrations of grapefruit juice and different doses of the cholesterol lowering drug simvastatin on the physiology and pathophysiology. So far, we assessed the potential risk of myopathy development due to the concomitant intake of GFJ and simvastatin. Non-fasted male Sprague-Dawley rats weighing 350 - 400 g were used and their body weight was checked daily. Grapefruit juice (GFJ) (5ml/kg) at different concentrations (double and normal strength), or water (5ml/kg) were administered together with their respective simvastatin dose (SVlowdose = 20 mg/kg Simvastatin, SVhighdose = 80 mg/kg Simvastatin) over a period of 4 consecutive weeks. The animals were fed GFJ and Simvastatin through an oral feeding needle daily. At the end of the study the rats were sacrificed, blood was be collected (for determination of simvastatin plasma levels) and muscle samples were taken to assess differences in muscle histology and organs will be weight to assess organ changes. During the study, one blood
sample of 1000 mcL was taken once a week right before dosing the drug. After the last blood sample of the chronic study phase, muscle strength parameters were measured. This was achieved using equipment where the rat holds on to a bar and is pulled back manually. The force after with the animal releases the bar is an indicator for is muscle strength. In addition, extremity temperature and open field parameters were evaluated. When GFJ was administered together with 20 or 80 mg/kg of simvastatin, a stable body weight development was observed. In addition, no changes in organ weights (e.g. liver, kidney, spleen, testes, heart, adrenals) were measured, indicating no signs of toxicity (decrease or increase of organ weights are the first signs of toxicity). All treatment groups also showed a stable grip strength development and a comparable paw temperature (a decrease in paw temperature is also a first sign of muscle toxicity). Further, no differences in the number of line crossings in the
open field were detected, indicating normal locomotor activity. Pharmacokinetic data as well as data regarding the muscle histology are currently under investigation.
Impacts
During the last years, many reports about interactions between various drugs and grapefruit juice have been published. It has become clear that several different mechanisms are involved in these interactions involving both drug metabolism and drug transporter systems. It is of critical importance to fully understand these mechanisms in order to manage and avoid these potential interactions. The research in this project contributes to a better understanding of these interaction mechanisms. It will allow to develop a rational approach to evaluate magnitude and relevance of the interaction and make recommendations for specific drugs. For example, for some drugs it has been shown that a grapefruit-juice induced elevation of drug concentrations is not of clinical consequence and hence insignificant. For other drugs, where the interaction with grapefruit juice may be of clinical concern, alternative drugs from the same class may be recommended which provide the same
therapeutic benefit but do not interact significantly with grapefruit juice. Results from our research demonstrate that polyphenolic components from grapefruit do have an inhibitory effect on the efflux-transporter P-gp. Overall, the research in this project provides valuable information regarding citrus compounds which have a potential to interact with drug-transport and also helps to develop and test alternative methods of juice production and breeding procedures with the goal of designing products with lower drug interaction potential.
Publications
- Variation of Flavonoids and Furanocumarins in Grapefruit Juices DE CASTRO, W.V., MERTENS-TALCOTT, S., RUBNER, A., BUTTERWECK, V., DERENDORF, H. J Agricul Food Chem 54(1):249-55 (2006)
- Grapefruit-drug interactions: can interactions with drugs be avoided? MERTENS-TALCOTT, S., ZADEZENSKY, I., DE CASTRO, W.V., DERENDORF, H., BUTTERWECK, V. Clin Pharmacol. 46 (12):1390-416 (2006)
- Grapefruit Juice Drug Interactions: grapefruit juice and its components inhibit P-glycoprotein mediated transport of talinolol in Caco-2 Cells DE CASTRO, W.V., MERTENS-TALCOTT, S.U., DERENDORF, H., BUTTERWECK, V. Lecture: 54th Annual Meeting of the Society of Medicinal Plant Research, Helsinki, Finland, August 29st - September 2nd, 2006
- Grapefruit Juice Drug Interactions: grapefruit juice and its components inhibit P-glycoprotein mediated transport of talinolol in Caco-2 Cells DE CASTRO, W.V., MERTENS-TALCOTT, S.U., DERENDORF, H., BUTTERWECK, V. Poster Presentation on the 47th Annual Meeting of the American Society of Pharmacognosy, Arlington, VA, USA, August 5th - 9th, 2006
- Effects of grapefruit juice and its components on the activity of P-glycoprotein DE CASTRO, V.W., TALCOTT, S., BUTTERWECK, V., DERENDORF, H. Posterpresentation on the AAPS Annual Meeting, San Antonio, October 2006
- Citrus flavonoids in the inhibition of P-glycoprotein in vitro TALCOTT, S., DE CASTRO, V.W., DERENDORF, H., BUTTERWECK, V. Poster Presentation on the AAPS Annual Meeting, San Antonio, October 2006
- Drug-Interactions of Grapefruit- and Other Citrus-Polyphenolics - What have we learned? MERTENS-TALCOTT, S.U., ZDROJEWSKI. I., DE CASTRO, W.V., BUTTERWECK, V., DERENDORF, H. In: FRANCIS LAM, Y.W., HUANG, S.M., HALT, S.D., Herbal Supplement-Drug Interactions, Taylor and Francis., New York, pp 147-190 (2006)
- Polymethoxylated flavones and other phenolic derivates from citrus in their inhibitory effects on P-glycoprotein-mediated transport of talinolol in Caco-2 cells. MERTENS-TALCOTT, S., DE CASTRO, W.V., MANTHEY, J.A., DERENDORF, H., BUTTERWECK, V. J Agric Food Chem. 55(7):2563-8 (2007)
- Grapefruit juice-drug interactions: Grapefruit juice and its components inhibit P-glycoprotein (ABCB1) mediated transport of talinolol in Caco-2 cells. DE CASTRO, W.V., MERTENS-TALCOTT, S., DERENDORF, H., BUTTERWECK, V.; J Pharm Sci (in press) 2007
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