Microdosing studies are effective in enabling the early identification of the pharmacokinetic properties of compounds administered to humans. However, the nonlinearity of the pharmacokinetics between microdose and therapeutic dose, attributable to the saturation of metabolic enzymes and transporters, is a major concern. Verapamil and quinidine are good substrates of both the multidrug...
The authors evaluated the contribution of the SLCO2B1 polymorphism to the pharmacokinetics of celiprolol at a microdose (MD) and therapeutic dose (TD) and compared pharmacokinetic proportionality between the 2 dose forms in 30 SLCO2B1 genotype-matched healthy volunteers. Three drugs (celiprolol, fexofenadine, and atenolol) were orally administered as a cassette dosing following the MD (totally...
Abstract BACKGROUND: As alkylating agents, platinum (Pt) analogs kill cancer cells mainly through induction of DNA damage. We hypothesize that low levels of Pt-induced DNA damage are predictive of chemoresistance. Accelerator mass spectrometry (AMS) is an ultrasensitive method for measuring radiocarbon with 10−18∼21 mole sensitivity. By measuring 14C bound to DNA, AMS detects...
264 Background: DNA damage is the critical step in cancer cell response to platinum (Pt) chemotherapy. We hypothesize that low levels of Pt-induced DNA damage are predictive of chemoresistance. Accelerator mass spectrometry (AMS) is an ultrasensitive method for measuring radiocarbon. By measuring 14C bound to DNA, AMS can detect carboplatin-induced DNA damage after patients receive one subtoxic...
The aim of the present study is to investigate the pharmacokinetics of our newly developed aromatase inhibitors (cetrozole and TMD-322) in healthy subjects by a cassette microdose strategy. A cocktail of cetrozole and TMD-322 was administered intravenously or orally (1.98 μg for each drug) to six healthy volunteers in a crossover fashion. Anastrozole (1.98 μg) was also included in the oral...
Formation and repair of platinum (Pt)-induced DNA adducts is a critical step in Pt drug-mediated cytotoxicity. Measurement of Pt-DNA adduct kinetics in tumors may be useful for better understanding chemoresistance and therapeutic response. However, this concept has yet to be rigorously tested because of technical challenges in measuring the adducts at low concentrations and consistent access to...
The microdose (MD) clinical study enables to select a "better" compound for new drug candidate that shows desirable PK profiles in human. This new methodology is highly expected to streamline the drug development and to increase the success probability in the clinical trial. Since only a small amount of the test compound (less than 100 μg) is administered, the risk of harmful events to a human...
Microdosing came onto the scene with the first publication of data in 2003. Since this time the number of compounds where the pharmacokinetics observed at a microdose compared to a therapeutic dose has grown steadily. Based on current data in the public domain, there are 23 drugs where microdose and therapeutic dose pharmacokinetics can be compared. Of these, 84% scale within a factor of 2 for...
Abstract BACKGROUND: DNA damage is the critical step in cancer cell response to platinum (Pt) chemotherapy. We hypothesize that low levels of Pt-induced DNA damage are predictive of chemoresistance. Accelerator mass spectrometry (AMS) is an ultrasensitive method for measuring radiocarbon. By measuring 14C bound to DNA, AMS can detect carboplatin-induced DNA damage after patients receive one...
The use of microdose pharmacokinetic studies as an essential tool in drug development is still to catch on. While this approach promises potential cost savings and a quantum leap in efficiencies of the drug development process, major hurdles still need to be overcome before the technique becomes commonplace and part of routine practice. Clear regulations in Europe and the USA have had an...