Gastrointestinal transit and digestibility of maltitol, sucrose and sorbitol in rats: a multicompartmental model and recovery study

Short-term digestive tolerance of chocolate formulated with maltitol in children

INTRODUCTION

Polyols are molecules of interest for food industries because of their technological and nutritional properties. Maltitol is known for its non-acidogenic and low-energetic properties. Our primary objective was to evaluate the digestive tolerance of maltitol in children. The secondary objective was to compare the organoleptic properties of maltitol and sucrose in chocolate.

METHOD

Healthy children were included in a double-blind, randomized parallel study versus placebo. The subjects received one dose of either maltitol or sucrose chocolate per week. Increasing doses were tested from 5 to 15 g maltitol in chocolate. Abdominal pain, rumbling, bloating and flatulence scores were evaluated using visual analog scales.

RESULTS

Some statistical differences on intestinal parameters were observed in the maltitol group compared with placebo, mainly concerning flatulence scores. Nevertheless, these scores remained low and could be considered minor.

CONCLUSION

Our results suggest that maltitol was well tolerated in children at 15 g in one intake.

A Modern View of Excipient Effects on Bioequivalence: Case Study of Sorbitol

PURPOSE

To examine the effect of common excipients such as sugars (sorbitol versus sucrose) on bioequivalence between pharmaceutical formulations, using ranitidine and metoprolol as model drugs.

METHODS

Two single-dose, replicated, crossover studies were first conducted in healthy volunteers (N=20 each) to compare the effect of 5 Gm of sorbitol and sucrose on bioequivalence of 150 mg ranitidine or 50 mg metoprolol in aqueous solution, followed by a single-dose, nonreplicated, crossover study (N=24) to determine the threshold of sorbitol effect on bioequivalence of 150 mg ranitidine in solution.

RESULTS

Ranitidine Cmax and AUC0-infinity were decreased by approximately 50% and 45%, respectively, in the presence of sorbitol versus sucrose. Similarly, sorbitol reduced metoprolol Cmax by 23% but had no significant effect on AUC0-infinity. An appreciable subject-by-formulation interaction was found for ranitidine Cmax and AUC0-infinity, as well as metoprolol Cmax. Sorbitol decreased the systemic exposure of ranitidine in a dose-dependent manner and affected bioequivalence at a level of 1.25 Gm or greater.

CONCLUSIONS

As exemplified by sorbitol, some common excipients have unexpected effect on bioavailability/bioequivalence, depending on the pharmacokinetic characteristics of the drug, as well as the type and amount of the excipient present in the formulation. More research is warranted to examine other 'common' excipients that may have unintended influence on bioavailability/bioequivalence.

Solution properties and sweetness response of selected bulk and intense sweeteners

Two bulk sweeteners (sucrose and maltitol) and four intense sweeteners (acesulfame K, aspartame, sodium cyclamate, and sodium saccharin) are used in this study. Densities and sound velocity values of the sweeteners in solution are measured at 20 degrees C, and their apparent molar and specific volumes, their isentropic apparent molar and specific compressibilities, as well as their compressibility hydration numbers are calculated and reported. The introduction of solute molecules in water results in a volume change of the solvent as a result of attractive forces exerted by the solute molecules; such forces are in the form of electrostrictive or hydrogen-bonding forces, or charge-dipole attraction. Changes of molar volumes with increasing concentration give an indication of the extent of solute-solute interaction, whereas isentropic compressibilities give a direct measurement of the state of hydration of the solute molecules. The compressibility hydration numbers reported give an indication of the number of water molecules disturbed by the presence of each solute molecule in solution. Isentropic compressibilities seem to be a more sensitive parameter for distinguishing the bulk sweeteners from the artificial sweeteners. The sweetness response of the sweeteners is then explained in terms of their solution behaviors.

Gastrointestinal transit and distribution of ranitidine in the rat

PURPOSE

Ranitidine gastrointestinal distribution was examined in the rat small intestine after oral administration to determine whether intestinal transit or secretion (exsorption) may influence the appearance of secondary peaks in ranitidine serum concentration-time profiles.

METHODS

Male Sprague-Dawley rats received ranitidine (50 mg/kg) by oral gavage, and the mass of ranitidine recovered in all small intestinal segments (approximately 12 cm each) was determined 30, 60, 90, or 120 min after administration. In a separate group of anesthetized rats, the small intestine was divided into two segments of equal length that were perfused with normal saline in a single-pass manner. Rats received an escalating, zero-order IV infusion of ranitidine for 30 min, and venous blood and intestinal effluent were collected over 90 min to quantitate ranitidine exsorption.

RESULTS

Thirty min after oral administration, > 50% of the recovered ranitidine mass resided in the lower half of the small intestine in all rats. Ranitidine mass in 5 of 16 rats displayed a bimodal distribution with significant amounts of ranitidine recovered from the stomach 60 to 90 min after dosing. Ranitidine exsorption was more efficient from the lower jejunum and ileum than from the duodenum and upper jejunum. However, intestinal secretion of ranitidine was minor (5% of the IV dose).

CONCLUSIONS

Ranitidine absorption from the lower ileum contributes significantly to systemic ranitidine concentrations before and during the time of the first concentration maximum. Separation of the drug mass into multiple boluses may contribute to secondary peaks in ranitidine concentration-time profiles. Exsorption did not contribute significantly to ranitidine distribution in the gastrointestinal tract.

Dose dependency of fermentation and the extent of renal excretion of palatinit (isomalt) in rats with respect to its energy value

The impact of dose-dependent caloric salvage by microbial fermentation processes in the lower gut and the extent of renal excretion for the overall energetic availability of the alternative bulk sweetener Palatinit were investigated in rats. To evaluate the extent of dose-dependent fermentation a conventional and a germ-free rat model were used and fecal excretions of Palatinit after intragastric application were compared. Because of the lack of bacterial colonization in the gastrointestinal tract in germ-free rat the difference in fecal excretion of Palatinit between germ-free and conventional rat is mainly due to bacterial fermentation. To determine the amount of renal excretion of Palatinit the urine was collected. The experiments were conducted using different amounts of Palatinit (300 and 1,200 mg/kg body weight = mg/kg b.w.). Fecal excretions of Palatinit and its monomers (sorbitol and mannitol) were measured by high-performance liquid chromatography (HPLC) and for the determination of renal excretions a gas chromatography system was used. After the application of 300 mg/kg b.w. Palatinit only the breakdown product sorbitol could be recovered in the feces of germ-free rats (29% of the applied dose). No intact Palatinit could be found. In contrast, neither Palatinit nor the breakdown products sorbitol or mannitol could be detected in the feces of conventional rats after application of the same dose. After the application of the higher dose only small amounts of intact Palatinit were found in the feces of germ-free rats (average 12%). There was no intact measurable Palatinit in the feces of conventional rats. The fecal excretions of sorbitol and mannitol in the feces of the germ-free rats were 55% and 39%; in conventional rats only 21% sorbitol was excreted. Only traces of Palatinit, sorbitol or mannitol were found in the urine of conventional and germ-free rats after application of the low as well as the high dose. In conclusion, this study clearly shows the dose dependency of fermentation and therefore the dose dependency of the energetic (i.e., caloric) availability of this disaccharide sugar alcohol. In the calculation of the energy value of Palatinit the renal excretion of Palatinit and its monomers can be neglected.