GB695787A - Improvements in anticoagulants - Google Patents

Abstract

The invention comprises the water-soluble salts of sulphuric esters derived from dextrans of intrinsic viscosity less than 0.04, said esters having 9 per cent or more of sulphur in their sodium salts. The compounds are made by the degradation of high molecular weight dextrans, fractionation of the mixture to remove products whose intrinsic viscosity is 0.04 or more, esterifying the lower fraction with a sulphating agent and converting the ester into a water-soluble salt, e.g. of an alkali or alkaline earth metal. The ester may have up to 3 sulphate groups per glucose unit and its sodium salt preferably has 14 per cent or more sulphur. The molecular weight is less than 22,000. An example is given of the preparation of a suitable ester-salt, using chlorosulphonic acid with pyridine for the esterification and sodium hydroxide for neutralization; the product has 17.15 per cent of sulphur. Specification 603,571 is referred to. According to the Provisional Specification the dextran may be any whose molecular weight is less than 25,000.ALSO:Anticoagulants for use with blood and plasma consist mainly or entirely of a water-soluble salt of dextran sulphate, the latter being the sulphuric ester of a dextran whose intrinsic viscosity is less than 0.04; the ester has a sulphur content of not less than 9 per cent calculated on its sodium salt. The ester may have up to 3 sulphate groups per glucose unit, the molecular weight being less than 22,000. A sterile isotonic solution can be made by autoclaving a solution of the salt together with sodium chloride and a buffer, e.g. sodium bicarbonate. The salt may be of an alkali or alkaline earth metal, especially sodium. A test is described to ensure that the anticoagulants are non-toxic in vivo. Specification 603,571 is referred to. According to the Provisional Specification there may be used any dextran whose molecular weight is less than 25,000.