Mannitol relative sweetness

The most important hexitols are o-glucitol and D-mannitol. The most important pentitol is xyhtol. The relative sweetness of both hexitols (in 10% solutions) and xyhtol, compared with saccharose, is about 60 and 100%, respectively. AU three polyols have very Kttle effect on blood glucose level and are therefore used as sweeteners for diabetics. However, their content must be included in the total energy intake. They exhibit mild laxative effects (such as prunes, which contain higher amounts ofglucitol than other fruits). 

Acid or enzymatic hydrolysis of sucrose, inversion, produces an equimolar mixture of n-glucose and n-fructose known as invert sugar. Invert sugar is used as a food additive substance, usually in the form of syrup (relative sweetness is 95-105% of saccharose sweetness). It also serves as a starting material for obtaining d-glucose and D-fructose, the sweeteners mannitol and glucitol and other substances. 

Most commercial ODTs have been developed using mannitol as the bulk excipient of choice because of its extremely low hygroscopicity, excellent compatibility, good compressibility, better sweetness, and relatively slower dissolution kinetics. Although lactose also has a relatively low aqueous solubility compared with other excipients that have acceptable palatabilities, the dispersibility of a bulk excipient is more important than its aqueous solubility for a successful ODT formulation. Many of the initially marketed ODTs were prepared by the wet granulation of mannitol followed by direct compression. However, added functionality mannitols are now available to simplify the process of ODT manufacturing by direct compression. 

This and other nonabsorbable sugars such as sorbitol and mannitol are hydrolyzed in the colon to short-chain fatty acids, which stimulate colonic propulsive motility by osmotically drawing water into the lumen. Sorbitol and lactulose are equally efficacious in the treatment of constipation caused by opioids and vincristine, of constipation in the elderly, and of idiopathic chronic constipation. They are available as 70% solutions, which are given in doses of 15 to 30 mL at night, with increases as needed up to 60 mL per day in divided doses. Effects may not be seen for 24 to 48 hours rafter dosing is begun. Abdominal discomfort or distention and flatulence are relatively common in the first few days of treatment but usually subside with continued administration. A few patients dislike the sweet taste of the preparations dilution with water or administering the preparation with fruit juice can mask the taste. 

Because mannitol and sorbitol are both moderately sweet and relatively inexpensive, they have been considered as special dietary constituents 63). The content of sorbitol in diabetic foods should be counted as available carbohydrate, and the label of foods containing sorbitol should indicate the amount present. Probably owing to the slow intestinal absorption of sorbitol, doses greater than 50 g. are laxative in humans, but smaller doses are well tolerated. Care needs to be exercised in determining more fully the possible harmful effect of ingesting considerable amounts of sugar alcohols, before their general use as food additives is accepted. 

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