Study on hydrophilic properties of gelatin as a clinical wound dressing. II. Water-absorbing property and hemostatic effect of gelatin.

For clinical use of gelatin as a dressing, we determined the water-absorbing capacity of gelatin for isotonic sodium chloride solution (ISCS) and bovine serum albumin-isotonic sodium chloride solution (BSA-ISCS). There was no significant difference between water absorption of gelatin with ISCS and with BSA-ISCS. The water-absorbing capacity of gelatin increased with increasing viscosity: gelatins No. 1 > No. 2 > No. 3. Enormous spaces of 20 to 30 microns or approximately 10 microns in size were observed on the gelatin surface. Scaly materials of 10 to 20 microns in size were also observed. The pores of 10 A in radius were predominant in all the gelatins studied. Since the sizes of cellular blood components range between 2 and 17 microns, they can enter the spaces but not the pores of 10 A in radius. On the other hand, water molecules, the major component of plasma, can enter the pores. Of theoretical sorption isotherms, Henderson's and Chung-Pfost's equations were fitted within the range of relative humidity between 1.5 and 75%. Gelatin No. 1 had the smallest constants n, K, B, and C followed by gelatins No. 2 and No. 3, suggesting that gelatin No. 1 is the most flexible for water and thus is fitted most easily to a raw area such as a wound or burn surface. The study of hemostatic effects of gelatin in rats demonstrated that when used at concentrations more than 50% of the bleeding amount, gelatin absorbed water from blood, and was stuck to and covered the wound surface.