Stability and osmolality of a nutritional food supplement during simulated nasogastric administration.

The stability and osmolality of a commercially available food supplement (Hepatic-Aid, American McGaw) was assessed during a simulated nasogastric feeding; the effects of dilution and adding a suspending agent were also determined. Four product samples of the food supplement were prepared: (1) normal reconstitution strength; (2) 25% normal reconstitution strength; (3) normal strength with 0.3% (w/w) suspending agent; and (4) 25% normal strength with 0.3% (w/w) suspending agent. The suspending agent was 60% carrageenan and 40% cellulose gum. Six-hour nasogastric feeding simulations were performed, and hourly fractions were collected. The freshly prepared samples, the hourly fractions, and the residue remaining in gavage containers and tubing were analyzed for gross composition, osmolality, and pH. During the six-hour period, fractions from the normal reconstitution strength product fluctuated in fat content, and the diluted product had variable fat and carbohydrate content. Adding a suspending agent stabilized fat in the normal but not in the diluted product. The pH, osmolarity, and amino-acid content remained relatively constant throughout the six-hour period in all four products. At no time did any of the products clog the tubing. The creaming and flocculation noted in all reconstituted products caused a slight variation in calories delivered during simulated nasogastric administration because of partial fat and carbohydrate destabilization; adding a suspending agent restored stability only in the normal reconstitution strength product. The critical amino acid content that is needed for the nutritional support of patients with hepatic encephalopathy was maintained in all products.