In Situ Intestinal Perfusion of Irinotecan: Application to P-gp Mediated Drug Interaction and Introduction of an Improved HPLC Assay

Abstract

-Purpose:To determine 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 as a model) on the permeability and toxicity of irinotecan. Methods: Single pass intestinal perfusion of rat's whole length small intestines is applied to assess the permeability of the parent drug and quantify the intestinally excreted metabolite. The perfusion solution contained 30μg/ml of irinotecan (control group) without or with verapamil (verapamil group). A simple reversed phase HPLC method with UV detection is developed and validated for simultaneous determination of irinotecan and SN-38 using camptothecin as an internal standard. Results: HPLC-UV method found to be simple, specific, accurate, and precise. Effective permeability coefficient of irinotecan found to be 4.9±1.7  10 -3 mm/min and was doubled in verapamil group (P=0.007). Average cumulative amount of SN-38 exsorbed found to be 29 ng/cm over 2 hours perfusion time which was decreased to 15 ng/cm in verapamil group (P=0.016). Conculsions: in situ intestinal perfusion method was successfully applied to quantify the permeability of irinotecan and the exsorption of SN-38 in the same experiment, in a manner that robustly reflects real in vivo situation. P-gp inhibition using verapamil found to significantly enhance the intestinal permeability of irinotecan and potentially decrease the intestinal toxicity due to SN-38 exposure.

Modulating TAK1 Expression Inhibits YAP and TAZ Oncogenic Functions in Pancreatic Cancer

“…Gemcitabine (Accord), oxalipatin (Accord), SN38 (Campto, ref. 17), and nab-paclitaxel (Celgene) were used at the indicated concentrations for the indicated time. The proteasome inhibitor MG132 (Z-Leu-Leu-Leu-al, C2211; Sigma-Aldrich) was dissolved in 100% DMSO and used at a 5 mmol/L concentration for 24 hours.…”

Mechanisms of chitosan-coated poly(lactic-co-glycolic acid) nanoparticles for improving oral absorption of 7-ethyl-10-hydroxycamptothecin

“…In situ single-pass intestinal perfusion (SPIP) was used for the evaluation of drug absorption according to the previously reported method [6,28]. Male Sprague-Dawley rats with body weights of 200-240 g were maintained in the laboratory animal facility (22 (±2) • C, 50 (±5)% relative humidity, 12 h light/dark cycle) provided with standard food and water for 7 days before starting the experiment.…”

Liquid chromatographic method for irinotecan estimation: Screening of p-gp modulators

“…Stability studies were performed in quality control samples to assess the stability of analyte in the Tyrode's solution, keeping our experimental condition in consideration. Experiments were performed to establish on-bench stability (25±2°, after 6 h), freeze thaw stability (3 cycles) and short-term stability at −20° for 30 days [16] .…”

“…Gradient-programmed HPLC method coupled with UV-detector was also reported but with a drawback of long run time of 35 min [1] . Furthermore, HPLC-UV analytical methods with lower run time were also reported [3,16] . However, these methods were not validated for their accuracy/recovery with wide range of excipients as per our review of literature.…”