Preclinical pharmacology and safety of a novel avidin derivative for tissue-targeted delivery of radiolabelled biotin.

We recently described an oxidized avidin variant, named AvidinOX(®) , which is a product that chemically links to tissue proteins while maintaining the capacity to uptake intravenously administered biotin. Such product proved to be successful in targeting radionuclide therapy in a mouse model of inoperable breast cancer. Here, we show that the uptake of a single or multiple doses of biotin (up to five times), by the tissue-bound AvidinOX(®) , is stable for 2 weeks.

L-carnitine esters as "soft", broad-spectrum antimicrobial amphiphiles.

A new class of antimicrobial, "soft", quaternary ammonium l-carnitine esters, of the type (CH3)3N+-CH2-CHOCO(R1)-CH2-COO(R2) Cl-, has been designed, with R1 and R2 being in general long-chain alkyl substituents. The series shows good activity against a wide range of bacteria, yeasts, and fungi. Lipophilicity has been measured by RP-HPLC method to give the logarithm of the experimental capacity factor (log k'), and a quantitative relationship has been determined between log k' and the theoretical partition coefficient (CLOGP); also, bond-dipole descriptors have been introduced into calculations by accounting for polar moieties present within the apolar cores of the molecules, giving a more refined calculated capacity factor (log k'calcd).

Evaluation of in vitro and in vivo antimicrobial activity of a new topical antiinfective agent.

ST 1103 (Undecyl [4-N,N,N-trimethylammonium-(R)-3- isovaleroyloxy]-butanoate methanesulfonate) is a novel compound endowed with a broad antimicrobial spectrum. ST 1103 is able to inhibit the in vitro growth of Gram-positive bacteria (mean MIC value of 2.60 micrograms/ml), Gram-negative bacteria (mean MIC value of 27.