Toxic and mutagenic effects of a low molecular weight heparin in rats.

Acute, subacute, chronic toxicity and mutagenicity studies of a new low molecular weight heparin (OP/LMWH) were carried out in rats. The LD50 values resulted lower by i.m. and s.c. route than after i.p. and i.v. administration. OP/LMWH given by subcutaneous route in subacute and in chronic toxicity produced no significant adverse effects at 5 mg/kg, only marginal effects at 10 mg/kg and moderate effects at the dose of 20 mg/kg. In these studies, unfractionated heparin at 10 mg/kg by s.c. route was used for comparison. At 10 mg/kg, heparin presented effects similar to those shown by OP/LMWH at 20 mg/kg. OP/LMWH did not show any mutagenic activity when compared with mutagenic standards.