Abstract 4257: Pharmacokinetics (PK) and tissue penetration of the novel VEGFR-3/FAK inhibitor, Chloropyramine

Abstract

Purpose: Previous reports demonstrate that chloropyramine has anti-tumor efficacy as a single agent, and in combination with cytotoxic agents like doxorubicin through modulation of the FAK-VEGFR-3 pathway. Since limited information is available about the pharmacokinetics of chloropyramine, we investigated the pharmacokinetics and tissue distribution of the drug following a single intraperitoneal (IP) injection. Methods: Female CD-1 mice received a single 50mg/kg dose of chloropyramine; plasma and tissue samples were collected at serial timepoints of 0.5, 1.0, 2.0, 4.0, and 6.0 hours. The tissues included brain, heart, spleen, liver, lung, muscle, and sternum. Each timepoint contained three mice. Chloropyramine concentrations were determined in both plasma and tissues, using a validated LC-MS/MS. Assay was validated with an LLOQ of 0.25ng/ml with the calibration curve ranging from 0.25-100ng/ml (3.42-12.4%CV). Noncompartmental PK analysis was performed using WinNonlin (Pharsight, Version 5.3). Pharmacokinetic parameters including: Maximal concentration (Cmax), terminal elimination half life (T1/2), area under the curve (AUC0-6hr), apparent clearance (Cl/F), apparent volume of distribution (Vd/F), and partition coefficients (Kp). Results: Following IP injection, chloropyramine followed either a mono- or bi-exponential decay in both plasma and tissues. Chloropyramine is cleared from plasma and all tissues within 12hr; thus chloropyramine does not exhibit a great potential for accumulation. Cmax was achieved within 1.0 hour for plasma and all tissues. Chloropyramine distributes well into various tissues such as the spleen, liver, lung, kidney, brain, and heart. The highest level of chloropyramine was achieved in lung tissue with a mean (sd) Cmax concentrations of 41.6 (11.6) μg/ml, respectively. In contrast, the mean Cmax in plasma was approximately 0.5 μg/ml; much less compared to tissues. The mean T1/2 was 0.83 (0.19) hr. The lungs exhibited the highest total tissue penetration of chloropyramine, representing a mean AUC of 51.3 μg-hr/g. The least total exposure was in muscle, with a mean AUC of 8.5 μg-hr/g. The apparent CL/F from plasma was 28.5 L/hr/kg while it was 0.9 L/hr/kg for lung tissue. Conclusions: These results illustrate the wide tissue distribution of chloropyramine, despite of the short plasma half-life. In addition, these results are of great importance because it provides supportive evidence of the tissue levels that will lead to anti-tumor efficacy through inhibition of FAK and VEGFR-3. Thus, evaluation of plasma and tissue concentrations of the drug elucidates the pharmacokinetics of this compound in an effort to identify target tissues into which it has a high degree of penetration to maximize antitumor efficacy. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 4257. doi:10.1158/1538-7445.AM2011-4257

Pharmacokinetic analysis of the FAK scaffold inhibitor C4 in dogs

“…Serum concentrations were detectable to 24 hrs with a mean concentration of 0.16±0.01 μg/mL; however, the assay limit of quantitation was not described. The rat T ½ and terminal concentrations reported by Kaverina are inconsistent with the observations reported in mice by Thudium (2011), who observed a T ½ of 0.83±0.34 hrs following a 44.6 mg/kg free base IV dose and no observable concentrations at 24 hrs despite having an analytical method with greater sensitivity. Although the animal species and route of administration are different (gavage in rats vs. IV in mice), some of the observations for the two rodent species are unexpected.…”

“…The concentrations of C4 remaining in the plasma at these latter time points were low (<35.0 pg/mL), and likely the result of slow C4 release after extensive tissue distribution as suggested by the large V ss . In the absence of tissue data from the current study, results from the IP administration of C4 to mice (Thudium 2011) support this premise. C4 concentrations in mouse plasma and tissues versus time profiles were obtained following 44.6 mg/kg IP administration of C4 free base to CD1 mice (n=3 per time point).…”

“…A stable-labeled C4 compound was not commercially available; therefore, N-DMP was chosen as the internal standard due to its close structural similarity and chemical behavior. We previously developed a protein precipitation LC-MS/MS assay to measure C4 in mouse plasma with linearity over the calibration range of 0.250 to 100 ng/mL using an AB Sciex API 3000 mass spectrometer (Thudium, 2011). Based on the proposed doses of C4 being administered to dogs, and the observed mouse pharmacokinetic data, a new assay was required with an approximate 40-fold increase in sensitivity (proposed LLOQ ∼6.0 pg/mL) in an attempt to quantify the 24 hr samples since none were detectable using the prior methodology for the mouse samples.…”

“…Since the intent is to develop C4 as an oncolytic agent in the United States, the corresponding preclinical studies need to be performed to define its pharmacokinetics and toxicology. The pharmacokinetics and tissue penetration of C4 in mice following intraperitoneal (IP) administration has been previously reported (Thudium et al 2011). The goals of this study included the development and validation of a highly sensitive and selective HPLC method with tandem mass spectral detection (LC-MS/MS), application of the method to quantitate C4 concentrations in dog plasma samples following IV and oral administration, and to characterize C4 pharmacokinetics.…”