No abstract

The radical H2C -CO -CH3 was produced in an acetone/H2O/H2O2 solution by photolysis using techniques similar to those developed by LIVINGSTON and ZELDES. The temperature dependence of the ESR spectrum indicates restricted rotation of the CH2-group relative to the rest of the molecule. A complete line-shape analysis of the spectrum at various temperatures leads to Arrhenius-para-meters Ea= (9.4 ± 0.5) kcal/mol and 10log k0 = 12.9 ± 0.3 which can be interpreted in the frame of the simple HMO theory.

Mathematically based pharmacokinetic models confirmed the general belief that intra-arterial (i.a.) cytostatic drug infusion can produce an increase in local tissue levels and a reduction in systemic drug availability. The increase in local drug concentration depends largely on the blood-flow rate of the infused artery and the rate of drug elimination from the rest of the body. In an experimental canine model the pharmacokinetics of i.a. infusion were studied using the femoral artery as the site of infusion and an Anger camera for continuous measurement of drug concentration in the target region. Several radioactively labelled drugs with different kinetics were infused over 80 min. The decay phase after the end of i.a. infusion was also monitored. The results indicate that even the femoral artery with its high blood flow is a suitable site for i.a. infusion, provided the plasma half-life of the drug is short enough. Consequently, arteries with lower blood flow (e.g., lingual artery) are even more suitable for i.a. infusion. The various diagrams obtained from this study provide a quick indication of whether or not a drug is suitable in a certain clinical situation.