Polyurethanes based on dihydroxamic acids. Synthesis, chemical characterization, and biological activity.

A series of segmented polyurethanes based on polyethylene oxide/polycaprolactone diol, isophorone diisocyanate, and dihydroxamic acids were synthesized and characterized. Biocompatibility and antitumoral activity were in vivo tested on Wistar male rats and Wistar rats affected with Walker 256 carcinosarcoma, respectively. The effect of dihydroxamic acid structure on the biological properties was determined.

Biological activity of maleic anhydride copolymers. I. Biocompatibility and antitumoural effects of maleic anhydride-vinyl acetate, maleic anhydride-methyl methacrylate and maleic anhydride-styrene copolymers.

A series of maleic anhydride (MA)-vinyl acetate (VA), MA-methyl methacrylate (MM), and MA-styrene (S) copolymers were prepared and characterized. On employing various amounts of initiator, maleic anhydride-vinyl acetate, methyl methacrylate, and styrene copolymers with molecular weights ranging between 18,000 and 200,000 have been obtained. The in vivo and in vitro tests performed on K562 cellular cultures (human chronic myeloid leukemia) have shown that, as a function of the molecular weight, the synthesized copolymers demonstrate a 50% in vitro cytotoxicity and an average tumour regression of maximum 68%.

Drug delivery systems based on inorganic materials: I. Synthesis and characterization of a zeolite-cyclophosphamide system.

Porous material of the CuX zeolite type has been synthesized and used as support for a classic antitumoral drug--cyclophosphamide (CP). The new material obtained represents a physical mixture of the two components. In vivo tests allowed biochemical and anatomopathological evaluation of antitumoral effects determined by oral administration of the CuX zeolite-CP system.

[The specific effects of new phenoxyacetic acid derivatives at the cellular membrane level].

Substances ASFA-2 and ASFA-4, new derivatives of phenoxyacetic acid, induce, in normal conditions, the hyperpolarization of the striated muscle fibre membrane, inhibition the depolarization due to the absence of external Ca2+, the restoration of membrane potential of the liver cells poisoned with ally alcohol and the change of redox potential of the environment. It results that these substances have important pharmacological properties--influence upon the membrane potential and cellular excitability, membrane stabilization, redox modulation and hepatic protection--that can be useful in therapy.