Pharmacokinetic Drug Interaction Studies of Irinotecan and Its Active Metabolite SN-38 with P-gp Inhibitors

论文摘要

In order to assess experimentally the intestinal permeability of the anticancer prodrug irinotecan, and to quantify the amount of its cytotoxic metabolite SN-38 that is intestinally excreted （exsorbed） as a predictor of intestinal toxicity, and to assess the effect of p-glycoprotein （P-gp） inhibitors （verapamil, pharmaceutical exipients, and grapefruit） on the permeability and toxicity of irinotecan, the improved form of the single pass intestinal perfusion （SPIP） model was used.And further in vivo experiments are done to further assess the pharmacokinetic interaction of P-gp inhibitors with irinotecan and its active metabolite SN-38 after oral administration of irinotecan.To achieve these goals, reversed phase isocratic high performance liquid chromatographic （HPLC） assay with UV detection is developed for quantification of irinotecan and SN-38 from perfusion samples, and from in vivo plasma samples.The HPLC-UV analytical method for the determination of the prodrug irinotecan and its active metabolite SN-38 was validated and found to be simple, specific, accurate, and precise. And used to apply the improved rat’s in situ single pass intestinal perfusion （SPIP） technique to assess the permeability, and intestinal toxicity of irinotecan predicted to result from exsorbed SN-38.The effects of P-gp inhibitor verapamil were also successfully evaluated and found to increase the intestinal permeability and potentially decrease the intestinal toxicity encountered upon the administration of irinotecan.The effects of commonly used exipients （Cremophor El, Tween 80） was also evaluated and proved ability to increase the permeability while little or no effect on the amount of SN-38 exsorption. The effect of PEG 400 was also investigated to assess its potential effect on the intestinal permeability of irinotecan and the exsorption of SN-38 but neither of the two parameters found to be changed.The effect of grapefruit was also investigated and found to increase the intestinal permeability and potentially decrease the intestinal toxicity encountered upon the administration of irinotecan （due to SN-38 gut exposure）.This method provided a useful tool for predicting oral absorption of irinotecan and the accompanying exsorbed SN-38 in the same experiment, in a manner that robustly reflects real in vivo situation.In addition the HPLC method was further validated for simultaneous assay of irinotecan and SN-38 from plasma samples, and found to be simple, specific, accurate, and precise, and was successfully applied to study the in vivo pharmacokinetics of irinotecan and SN-38 in rats, and to assess the effects of the P-gp modulators Cremophor El, Tween 80, and grapefruit, on the pharmacokinetic parameters of irinotecan and SN-38 compared to control.Introduction1.1. BackgroundIrinotecan 7-ethyl-10-[4-（1-piperidino）-1-piperidino]carbonyloxycamptothecin, also known as CPT-11, is a semisynthetic analog of the naturally occurring alkaloid, camptothecin （CPT）. Irinotecan has been widely used for the treatment of colorectal cancer as both first-and second line-therapy （Potmesil,1994）. Irinotecan has also shown clinical activity against colorectal, lung, gastric, cervical and ovarian cancers, malignant lymphoma and other malignancies (Ohno et al.,1990; Fukuoka et al.,1992;

论文目录

• Abstract
• Introduction
• 1.1. Background
• 1.2. Metabolism and excretion of irinotecan
• 1.3. Role of drug efflux transporters in irinotecan disposition
• 1.4. The Oral Route for Irinotecan Administration
• 1.5. HPLC Assay of Irinotecan and SN-38
• 1.6. The Aim of this Work
• Experimental Part
• 1. Materials
• 2. High Performance Liquid Chromatographic Analysis of Irinotecan and SN-38
• 2.1 Instruments
• 2.2 Chromatographic Conditions for intestinal perfusion samples
• 2.2.1. Mobile phase composition and preperation
• 2.2.3. Instrument adjustment
• 2.2.4. Preparation of Stock and Standard Solutions
• 2.2.5. Sample Preparation
• 2.3 Chromatographic Conditions for analysis of blood samples
• 2.3.1. Mobile phase composition and preperation
• 2.3.3. Instrument adjustment
• 2.3.4. Preparation of Stock and Standard Solutions
• 2.3.5. Sample Preparation
• 2.4. HPLC Method validation for the intestinal perfusion experiments
• 2.4.1 Specificity
• 2.4.2 Linearity
• 2.4.3 Accuracy and precision
• 2.4.4 Recovery
• 2.4.5. Stability studies
• 2.4.6 Lower limits of detection and quantification
• 2.5. HPLC Method validation for the in vivo pharmacokinetic experiments
• 2.5.1 Specificity
• 2.5.2 Linearity
• 2.5.3 Accuracy and precision
• 2.5.4 Recovery
• 2.5.5. Stability studies
• 2.5.6 Lower limits of detection and quantification
• 3. In Situ Single Pass Intestinal Perfusion experiments
• 3.1. Animals
• 3.2 preperation of the Perfusion Solution
• 3.3. Improved In Situ Single Pass Intestinal Perfusion Experiments
• 3.4. Data Analysis and Statistics
• 4. In Vivo Pharmacokinetic experiments
• 4.1. Animals
• 4.2. Animals grouping and drug dosage
• 4.3. Drug solutions preparation
• 4.4. Blood sampling
• 4.5. Pharmaco kinetic Data Analysis
• Results and Discussions
• 1. High Performance Liquid Chromatographic analysis of irinotecan and #23 SN-38
• 1.1 Chromatographic Method for analysis of perfusion samples
• 1.1.1 Specificity
• 1.1.2 Linearity
• 1.1.3 Accuracy and precision
• 1.1.4 Recovery
• 1.1.5 Stability
• 1.1.6 Lower limits of detection and quantification
• 1.2 Chromatographic Method for analysis of plasma samples
• 1.2.1 Specificity
• 1.2.2 Linearity
• 1.2.3 Accuracy and precision
• 1.2.4 Recovery
• 1.2.5 Stability
• 1.2.6 Lower limits of detection and quantification
• 2. Rat's Single Pass Intestinal Perfusion Experiments
• 2.1. Irinotecan-verapamil interaction
• 2.2. Irinotecan Excipients Interaction
• 2.2.1. Cremophor EL
• 2.2.2. Tween 80
• 2.2.3. PEG 400
• 2.3. Irinotecan-Grapefruit interaction
• 3. In vivo Pharmacokinetic experiments
• 3.1 Cremophor El-irinotecan interaction
• 3.2. Tween 80-irinotecan interaction
• 3.3. Grapefruit-irinotecan interaction
• Conclusions
• Acknowledgments
• Publications
• References
• Review
• References