Pharmacokinetic Modeling and Prediction of Plasma Pyrrole-Imidazole Polyamide Concentration in Rats Using Simultaneous Urinary and Biliary Excretion Data

Abstract

Pharmacokinetic (PK) modeling has been proposed as a means to improve the efficiency of drug development. It is difficult to develop an appropriate pharmacokinetic model if the lower limit of quantification (LLOQ) of the assay of the plasma drug concentration is high. The mathematical method of determining the plasma drug concentration below the LLOQ was discussed previously. 1,2) The method of analyzing the data including the urine concentration to construct the PK model that cannot be constructed using only plasma concentration data has also been reported.3) Not only the plasma concentration data but also urine and bile data collected over time provided information that was used as basis for the development of a PK model. Although the use of serum or plasma concentration-time profiles was primarily recommended, the use of urinary and/or biliary excretion data was regarded as an alternative approach if the bioanalytical method lacked the appropriate sensitivity to adequately characterize the serum or plasma concentration-time profile. This approach is considered to be used for the analysis of plasma concentration-time profile under LLOQ of various analytical instruments.The purpose of this study was to develop a PK model that describes the plasma concentration profiles under LLOQ of HPLC using urinary and biliary excretion data, and we used pyrrole (Py)-imidazole (Im) polyamides as model compounds. MATERIALS AND METHODS Chemicals and ReagentsThe Py-Im polyamides 1035 and 1666 reported previously 4) were purchased from Gentier Biosystems Co., Ltd. (Kyoto, Japan). Py-Im polyamide 1035 is composed of Ac-ImPyPy-g-ImPyPy-b-Dp (b: b-alanine, Dp: N,N-dimethylaminopropylamine, g: g-butyric acid), and Py-Im polyamide 1666, with a higher molecular weight, is composed of Ac-PyPy-b-PyImPy-g-PyPyPy-b-ImPy-b-Dp. The molecular weights of Py-Im polyamides 1035 and 1666 calculated on the basis of standard atomic weights 5) are 1035.12 and 1665.78, respectively. HPLC-grade methanol, acetonitrile, and distilled water were purchased from Kanto Chemical Co., Inc. (Tokyo, Japan). Midazolam and all other reagents of the highest quality were purchased from Wako Pure Chemical Industries, Ltd. (Tokyo, Japan). Pooled rat liver microsomes, pooled human liver microsomes, reduced nicotinamide adenine dinucleotide phosphate (NADPH) regenerating system solution, 1Ј-hydroxymidazolam, and 4-hydroxymidazolam were purchased from BD Bioscience (Woburn, MA, U.S.A.).Analysis of Py-Im Polyamides Unchanged Py-Im polyamides 1035 and 1666 were extracted from rat urine and bile by solid-phase extraction using Oasis ® WCX and MAX cartridges with both reverse-phase and ion-exchange sorbents. The HPLC method was based on a previous report with minor modification.4) The quantitative analyses of PyIm polyamides 1035 and 1666 including the preparation procedure have been validated using the criteria of the Food and The use of urinary and/or biliary excretion data was considered as an alternative approach if the bioanalytical method lacked the appropriate sensi...

Gene expression changes in a tumor xenograft by a pyrrole-imidazole polyamide

“…Efforts of Nagashima et al established that Py-Im polyamides of different architecture were detectable in rat serum several hours after intravenous (i.v.) administration (12). Matsuda et al further showed that a Py-Im polyamide targeted to the TGF-β1 promoter affected target gene expression in vivo (rat renal cortex) without evidence of systemic toxicity (13,14).…”

Crosstalk of the Androgen Receptor with Transcriptional Collaborators: Potential Therapeutic Targets for Castration-Resistant Prostate Cancer

“…Previous reports have shown that PI polyamides are not absorbed from the intestine [133]. After transvenous distribution in rat organs, PI polyamides were excreted into urine and bile without any metabolism [133,134].…”

“…Previous reports have shown that PI polyamides are not absorbed from the intestine [133]. After transvenous distribution in rat organs, PI polyamides were excreted into urine and bile without any metabolism [133,134]. Matsuda et al showed that PI polyamides accumulated in nuclei of kidney cells in rats and were maintained for about two weeks without any drug delivery system [135,136].…”

Pyrrole-Imidazole Polyamides for Gene Therapy: Bioanalytical Methods and Pharmacokinetics

“…The LLOQ was determined as 1 µg/mL for both PI polyamides A and B. All of the methods were successfully applied to evaluate the pharmacokinetics of the PI polyamides (Fukasawa et al, 2009;Fukasawa et al, 2007;Nagashima et al, 2009b Intra-assay Inter-assay Matrix Table 1. Intra-and inter-assay accuracy and precision for the determination of PI polyamides A and B in rat plasma and urine.…”

“…To predict the effective dose of PI polyamide B in Dahl-S rats administered at 1 mg every 2 or 3 days for 4 weeks, pharmacokinetic simulations of PI polyamide B were performed using a slightly modified pharmacokinetic model (Nagashima et al, 2009b) by NONMEM program. The average plasma concentrations of PI polyamide B after the administration at 1 mg every 3 and 2 days were 0.18 and 0.28 µg/mL, respectively, which were calculated by the area under the concentration-time curves between 0 and 27 days, divided by 27 days.…”