GB863544A - Improvements in or relating to blood plasma substitutes - Google Patents

Abstract

A blood plasma substitute comprises a 0.2-0.4% w/v. sterile aqueous solution of purified sodium alginate containing dissolved glucose, the specific viscosity of the solution being between 1.5 and 2.3. The solution preferably contains 5% w/v. glucose. It is prepared by treating a high-quality seaweed with aqueous alkali to remove the epidermis, a solution of sodium alginate in aqueous alkali being formed, separated and alginic acid gel precipitated by addition of organic or inorganic acid, the gel being redissolved in alkali and reprecipitated with acid, the step of redissolution and precipitation with acid being repeated if desired one or more times, the alginic acid gel finally obtained being washed with hot purified water to remove substantially all added acid and redissolved in aqueous alkali to form an aqueous solution of sodium alginate which is then coagulated by addition of an alcohol to yield solid sodium alginate which is then dissolved in glucose solution and heat sterilized. Riziri seaweed is preferably used. The precipitating acid is preferably hydrochloric; sulphuric and oxalic are also evaluated. Sodium hydroxide or carbonate may be used as the alkali. The sodium alginate solution is preferably filtered through a bag filter after the first alkali treatment, and is preferably filtered through paper pulp with or without charcoal or diatomaceous earth after each alkali redissolution step. The alcohol precipitation is preferably effected with methanol, preferably at a concentration above 45% and preferably at a pH of about 7.5 to 8, and then dehydrated by progressively increasing concentrations of alcohol.