Pharmacokinetic and Pharmacological Aspects of a Papain-Based Enzyme Solution for Rescuing Clogged Enteral Feeding Tubes.

Successful enteral feeding depends on patent enteral feeding tubes to permit trouble-free entry of nutritional formula into the alimentary tract. However, tube clogs can be a challenging complication of enteral feeding. This report addresses questions about using a papain-based enzyme solution to unclog enteral feeding tubes, including any effects that papain may have on patients and if solution use should be contraindicated in patients on ketogenic diets. The gastrointestinal tract is not permissive for significant papain activity and papain absorbed into the blood would likely be neutralized by antiproteases. In vitro examinations do not suggest toxic effects of papain in vivo, and those recognized in the latter setting are due to papain loads that exceed those used to unclog enteral feeding tubes. Allergies to papain occur infrequently and are probably attributable to an immunoglobulin E-mediated reaction to this enzyme. Although the amount of carbohydrate consumed upon single use of the unclogging solution is very low, a provider should decide whether using the papain-based enzyme solution for enteral feeding purposes is appropriate in patients who practice ketogenic diets. The benefits of using the papain-based enzyme solution to unclog enteral feeding tubes appear to outweigh any risks associated with its use.

The methanol method for the quantification of ascorbic acid and dehydroascorbic acid in biological samples.

We present a fast to perform spectrophotometric method for the quantification of ascorbic acid and its oxidized form dehydroascorbic acid in biological samples. The assay detects a chromophore formed during the reaction of dehydroascorbic acid with methanol in phosphate/citrate buffer. This reaction can also be employed for the determination of ascorbate (vitamin C) in the presence of ascorbate oxidase. The major advantage of the developed protocol for the determination of both forms of vitamin C is a simple spectrophotometrical single end point determination. It is demonstrated that the methanol method is an improvement compared with a commercially available test kit for the determination of vitamin C. Using the methanol method, a dose-dependent increase in intracellular ascorbic acid was determined upon incubation of L-929 cells and RAW 264.7 macrophages with increasing concentrations of extracellular ascorbate. In blood serum, vitamin C was determined at concentrations between 46 and 97 microM. Supplementation with different amounts of ascorbate showed satisfying recovery. In L-929 cells, even unphysiologically high amounts of reactive nitrogen species were unable to completely oxidize intracellular vitamin C.