Stability of vancomycin in icodextrin peritoneal dialysis solution.

BACKGROUND: Icodextrin is a glucose polymer used as an alternative osmotic agent in peritoneal dialysis (PD) solutions. There are few data regarding the long-term stability of vancomycin in icodextrin PD solution. OBJECTIVE: To determine the chemical stability of vancomycin in icodextrin PD solution in polyvinyl chloride containers over a 7 day period at 4, 24, and 37 degrees C. METHODS: Study samples were prepared by adding 2000 mg vancomycin HCl to commercially available 2.0 L bags of icodextrin 7.5% PD solution. Nine bags were prepared and stored in the following conditions: 3 under refrigeration (5 degrees C), 3 at room temperature (24 degrees C), and 3 at body temperature (37 degrees C). Samples were withdrawn from each bag immediately after preparation and at predetermined intervals over the subsequent 7 days. Solutions were visually inspected for precipitation, cloudiness, or discoloration at each sampling interval. Total concentration of vancomycin in dialysate fluid was determined by high performance liquid chromatography. RESULTS: Under refrigeration, a mean +/- SD of 99.7% +/- 0.5% of the initial vancomycin concentration remained at 168 hours (7 days). At room temperature, 97.5% +/- 3.4% remained at 168 hours. At body temperature, 94.3% +/- 3.9% remained at 24 hours. Stability was not assessed beyond these time points. CONCLUSIONS: Premixed vancomycin-icodextrin PD solutions, whether stored refrigerated or at room temperature, were found to be stable for up to 7 days. However, we recommend that these solutions be kept refrigerated whenever possible. Solutions stored at body temperature were stable for up to 24 hours, permitting the practice of prewarming solutions prior to administration.

De facto molecular weight distributions of glucans by size-exclusion chromatography combined with mass/molar-detection of fluorescence labeled terminal hemiacetals.

A major capability of polysaccharides in aqueous media is their tendency for aggregation and dynamic formation of supermolecular structures. Even extended dissolution processes will not eliminate these structures which dominate many analytical approaches, in particular absolute molecular weight determinations referring to light scattering data. An alternative approach for determination of de facto molecular weight for glucans with free terminal hemiacetal functionality (reducing end group) has been adjusted from carbohydrates for midrange and high-dp glucans: quantitative and stabilized labeling as aminopyridyl-derivatives (AP-glucans) and subsequent analysis of SEC-separated elution profiles based on simultaneously monitored mass and molar fractions by refractive index and fluorescence detection. SEC-DRI/FL of AP-glucans proved as an appropriate approach for determination of de facto molecular weight of constituting glucan molecules even in the presence of supermolecular structures for non-branched (pullulan), branched (dextran), narrow distributed and broad distributed and for mixes of compact and loose packed polymer coils (starch glucan hydrolizate).

Influence of dietary beta-glucan on growth performance, nonspecific immunity, and resistance to Streptococcus suis infection in weanling pigs.

Three experiments, using 344 pigs, were conducted to evaluate the influence of beta-glucan on growth performance, neutrophil and macrophage function, haptoglobin production, and resistance to Streptococcus suis challenge in weanling pigs. In Exp. 1, 144 pigs were used to evaluate the influence of .1% dietary beta-glucan in a soybean meal- or milk protein-based diet on growth performance and neutrophil function. Pigs fed beta-glucan from d 7 to 14 after weaning had lower ADFI (P < .01) and, although not significant, ADG was lower for pigs fed beta-glucan than for pigs fed control diets. However, no differences were observed in growth performance or neutrophil function for pigs fed control or diets containing beta-glucan from d 7 to 35 after weaning. Experiment 2 was a 28-d growth assay in which pigs were fed a diet with or without .1% beta-glucan, containing 7.5% spray-dried plasma protein and 25% dried whey from d 0 to 14 after weaning. Pigs then were fed corn-soybean mealbased diets containing 2.5% spray-dried blood meal and 10% dried whey. No differences in growth performance were observed. Experiment 3 was a 35-d assay to evaluate growth performance, neutrophil and macrophage function, and plasma haptoglobin concentration. Pigs were challenged on d 28 postweaning with intravenous S. suis. In Exp. 3, pigs were fed diets without or with .025 or .05% beta-glucan. Dietary beta-glucan did not influence neutrophil or macrophage function. However, pigs fed diets containing .025% beta-glucan had increased (P < .05) ADG and ADFI and were heavier (P < .05) on d 28 after weaning than pigs fed the control diet. No differences in feed efficiency (G/F) were detected between treatments. Pigs fed beta-glucan had decreased (P < .10) plasma haptoglobin on d 14, 21, and 28 after weaning. However, Fisher's Exact test revealed that more (P < .04) pigs fed a diet containing .025% beta-glucan died by d 12 after challenge with S. suis. In conclusion, these data suggest the existence of a complex interaction involving growth performance and resistance to S. suis in pigs fed .025% beta-glucan.

Composition and preliminary evaluation of a hydrolyzed rice-based oral rehydration solution for the treatment of acute diarrhea in children.

OBJECTIVE: The purpose of this study was to experimentally develop and clinically evaluate the safety and potential usefulness of a rice-based, short glucose polymer oral rehydration solution (ORS), Amylyte, in the treatment of acute diarrhea. Amylyte has a similar osmolality but a higher caloric density than the WHO ORS. METHODS: Different amounts of rice were cooked in 500 ml of water containing salts (1.5 g NaCl, 600 mg KCl, and 150 mg CaCl2) with varying amounts of thermophilic amylase (252,500 modified Wohlgemuth units). Amylase (25 mg) thinned the gluey rice water when 100 g of rice was cooked in 500 ml of water for 10 minutes. The volume of the resultant supernatant (Amylyte) was approximately 250 ml. A two-part, clinical case study was performed. In study 1, 12 children with diarrhea and mild dehydration were studied to determine the safety of Amylyte. In study 2, Amylyte and the WHO ORS were given to 24 and 31 male children with acute diarrhea and moderate to severe dehydration, respectively. RESULTS: 92-96% of the rice amylose and amylopectin were converted to short polymers of glucose (3-9 molecules of glucose). The osmolality of 7,994 packages used to make the Amylyte solution ranged between 277-340 mOsm/kg. The mean electrolyte composition was Na+ = 68 mEq/L, K+ = 20 mEq/L, Cl = 73 mEq/L, the caloric density 425 kcal/L and rice proteins 0.7 g/L. In study 1, 12 children with diarrhea and mild dehydration were rehydrated successfully with Amylyte ORS and the diarrhea ceased within 48 hours. None developed clinical features of carbohydrate intolerance. In study 2, an open-label clinical case study, children with acute diarrhea given Amylyte ORS had significantly less stool output than children given the WHO ORS. CONCLUSIONS: Amylyte ORS has the advantages of a higher caloric density than the WHO ORS and shares a simple preparation of appropriate osmolality and electrolyte composition. It can safely and effectively rehydrate children with acute diarrhea and dehydration.