Does leucovorin alter the intratumoral pharmacokinetics of 5-fluorouracil (5-FU)? A Southwest Oncology Group study

Polyamidoamine Dendron-Bearing Lipids as Drug-Delivery Excipients

An amine-terminated polyamidoamine (PAMAM) dendron and two long alkyl groups were designed as a novel drug carrier that possesses an interior for the encapsulation of drugs and a biocompatible surface. We synthesized three dendron-bearing lipids, DL-G1, DL-G2, and DL-G3, which included first, second, and third generation polyamidoamine dendrons, respectively. The synthesized dendrimer encapsulating anticancer drug, 5-fluorouracil (5-FU), was prepared by extraction with chloroform from mixtures of the dendrimers and varying amounts of the drug. In vitro cytotoxicity of PAMAM conjugated di-n-dodecylamine micelles (G1, G2, G3) were analyzed on human gastric adenocarcinoma cells (AGS) by water-soluble tetrazolium-1 (WST-1) cell proliferation assay. Upon exposure to 5-FU loaded micelles, the viability of the cells decreased gradually in all generations. Cytotoxicity increased with increasing generation and reached its highest rate of 69.8 ± 3.2% upon 15 µM 5FU-loaded 25 µM PAMAM DL-3 micelle treatment. These results demonstrate that 5FU-loaded PAMAM conjugated di-n-dodecylamine treatment inhibits the proliferation of AGS cells in a generation-dependent manner.

A novel 5-Fluorocuracil multiple-nanoemulsion used for the enhancement of oral bioavailability in the treatment of colorectal cancer

5-Fluorouracil (5-FU) is a drug of choice for colorectal-cancer. But oral therapeutic efficacy of 5-FU is restricted due to their very little bioavailability because of poor membrane permeability and GIT-absorption. We have developed a multiple nanoemulsion (w/o/w i.e. 5-FU-MNE) in which 5-FU incorporated to improve their oral-absorption. Globule-size of opt-5-FU-MNE was 51.64 ± 2.61 nm with PDI and ZP 0.101 ± 0.001 and −5.59 ± 0.94, respectively. In vitro 5-FU-release and ex vivo permeation studies exhibited 99.71% release and 83.64% of 5-FU from opt-nanoformulation. Cytotoxic in vitro studies-exhibited that 5-FU in opt-5-FU-MNE was 5-times more potent than 5-FU-S on human-colon-cancer-cell-lines (HT-29). The enhanced C_max with AUC_0-8h with opt-5-FU-MNE was shown extremely significant (p < 0.001) in wistar rat’s plasma in the comparison of oral and i.v. treated group of 5-FU-S by PK-observations. Furthermore, opt-5-FU-MNE was showed much more significant (p < 0.001) results as compared to 5-FU-S (free) on cell lines for human colon cancer (HT-29).

Cholesterol-Conjugate as a New Strategy to Improve the Cytotoxic Effect of 5-Fluorouracil on Liver Cancer: Impact of Liposomal Composition

Purpose:

Hepatocellular carcinoma (HCC) is a common liver malignancy, which has a low survival rate of all cancers. 5-fluorouracil (5-FU) is clinically recognized to treat HCC. However, the success of this therapy is highly limited due to rapid clearance and non- selective distribution. Cholesterol- conjugate (5-FUC) loaded liposomes proposed to facilitate the transport of 5-FUC into tumor cells via Low-Density Lipoprotein receptor (LDL receptor) that overexpressed in HCC. Thus, the aim of this study was to use 5-FUC loaded liposome as a promising strategy to combat HCC and improve the response of HCC to chemotherapy.

Methods:

5-FUC and 5-FU loaded liposomes were optimized based on Cholesterol (CHO) ratio and type of phospholipid to achieve a potential effect on HCC. Liposomes were prepared by the thin-film hydration method, and evaluated in terms of particle size, polydispersity, zeta potential, Entrapment Efficiency (EE), morphology, drug release and cytotoxicity.

Results:

The obtained liposomes had a suitable nano-range particle size with negative zeta potential, and acceptable EE%. In vitro drug release of 5-FUC loaded liposomes showed a lower cumulative release over 24 h as compared to 5-FU loaded liposomes. 5-FUC loaded liposomes exhibited a higher in vitro cytotoxic effect as compared to the free drug and 5-FU loaded liposomes against HepG2 cell lines after 48 h via MTT assay.

Conclusion:

These results concluded that 5-FUC loaded liposomes could be used as an alternative tactic to increase the therapeutic index of 5-FU and pave the way for potential clinical applications.

The Unique Pharmacometrics of Small Molecule Therapeutic Drug Tracer Imaging for Clinical Oncology

Simple Summary

New clinical radiology scans using trace amounts of therapeutic cancer drugs labeled with radioisotope injected into patients can provide oncologists with fundamentally unique insights about drug delivery to tumors. This new application of radiology aims to improve how cancer drugs are used, towards improving patient outcomes. The article reviews published clinical research in this important new field.

Abstract

Translational development of radiolabeled analogues or isotopologues of small molecule therapeutic drugs as clinical imaging biomarkers for optimizing patient outcomes in targeted cancer therapy aims to address an urgent and recurring clinical need in therapeutic cancer drug development: drug- and target-specific biomarker assays that can optimize patient selection, dosing strategy, and response assessment. Imaging the in vivo tumor pharmacokinetics and biomolecular pharmacodynamics of small molecule cancer drugs offers patient- and tumor-specific data which are not available from other pharmacometric modalities. This review article examines clinical research with a growing pharmacopoeia of investigational small molecule cancer drug tracers.

Magnetic resonance spectroscopy of cancer metabolism and response to therapy

Magnetic resonance spectroscopy allows noninvasive in vivo measurements of biochemical information from living systems, ranging from cultured cells through experimental animals to humans. Studies of biopsies or extracts offer deeper insights by detecting more metabolites and resolving metabolites that cannot be distinguished in vivo. The pharmacokinetics of certain drugs, especially fluorinated drugs, can be directly measured in vivo. This review briefly describes these methods and their applications to cancer metabolism, including glycolysis, hypoxia, bioenergetics, tumor pH, and tumor responses to radiotherapy and chemotherapy.

Chemotherapy Dosing Part I: Scientific Basis for Current Practice and Use of Body Surface Area

Cytotoxic chemotherapy is characterised by a low therapeutic index and significant variability in therapeutic and toxic effects. In an attempt to reduce this variability, most chemotherapy doses are individualised according to patient body surface area (BSA). This practice, which was introduced almost 50 years ago, clearly has practical and economic implications for the healthcare system. Furthermore, the clinical value of this approach has, in recent years, been questioned. Despite established practice, chemotherapy dose selection remains complicated, partly because treatment effects are difficult to measure, partly because drugs are used in combination with other treatment modalities, and also because the patient's condition may change with disease progression. Various patient-related factors can affect drug pharmacokinetics (PK) and pharmacodynamics (PD), for example organ function, expression and activity of metabolising enzymes, drug resistance, body size, gender, age, concomitant disease and co-administration of other drugs. These factors may be of clinical significance in chemotherapy dose determination and measures of PK, PD or both feature in attempts to devise more rigorous methods for chemotherapy dosing. Part I of this series of two reviews describes the history and clinical impact of BSA-based chemotherapy, and examines the scientific evidence to support BSA dosing. It evaluates the factors affecting PK and PD for specific drugs that could inform and refine dose determination.

Monitoring fluoropyrimidine metabolism in solid tumors with in vivo (19)F magnetic resonance spectroscopy

(19)Fluorine magnetic resonance spectroscopy ((19)F MRS) offers unique possibilities for monitoring the pharmacokinetics of fluoropyrimidines in vivo in tumors and normal tissue in a non-invasive way, both in animals and in patients. This method may therefore be useful for predicting response to fluoropyrimidine-based therapy with or without the effects of modulating agents, and this may be of value for the individualization of anticancer therapy and the strategic development of new anticancer drugs. (19)F MRS has been very valuable in elucidating the basic aspects of fluoropyrimidine metabolism, especially in animal studies. Studies in humans have indicated its clinical potential, but widespread application has been hampered by the relatively low detection sensitivity of the method. The recent introduction of clinical MR scanners with magnetic fields above 1.5 T may stimulate increased clinical use of (19)F MRS.