Sweetening agents are employed in liquid formulations designed for oral administration specifically to increase the palatability of the therapeutic agent. The main sweetening agents employed in oral preparations are sucrose, liquid glucose, glycerol, sorbitol, saccharin sodium and aspartame. The use of artificial sweetening agents in formulations is increasing and, in many formulations, saccharin sodium is used either as the sole sweetening agent or in combination with sugars or sorbitol to reduce the sugar concentration in the formulation. The use of sugars in oral formulations for children and patients with diabetes mellitus is to be avoided.

Following is the list of sweetening agents.

Bulk sweeteners Artificial sweetening agents
Sugars : xylose, ribose, glucose, mannose, galactose, fructose, dextrose, sucrose, maltose Sodium cyclamate
Hydrogenated glucose syrup Na saccharin
Sugar alcohols : sorbitol, xylitol, mannitol, glycerin Aspartame
Partially hydrolysed star Ammonium glycyrrhizinate
Corn syrup solids Mixture of thereof

Bulk Sweeteners
Used to replace sucrose and glucose syrups. One example is hydrogenated glucose syrup, in which the free aldehyde group of glucose has been reduced to sorbitol by catalytic hydrogenation; effectively a mixture of glucose and sorbitol. Used in soft drinks and sugar confectionery, and in some diabetic foods as a partial substitute for sorbitol; is 70-80% as sweet as sucrose. Hydrogenated glucose syrup can be used at concentration of 55-70 % w/w, when alginate is absent.

A bulk sweeter is used at concentration of 15-70 % w/w of the total weight of the suspension. This concentration is dependent on presence of other ingredient such as alginate, which have thickening effect. For example, in presence of alginate, sorbitol is used at concentration of 35-55 % particularly at 45 % w/w of the total suspension composition.

Combination of bulk sweeteners can also be used. e.g. Combination of sorbitol and hydrogenated glucose syrup or sucrose and sorbitol. Generally the taste-masking composition consists of at least one sweetening agent and at least one flavoring agent.
Sugar sweetener concentration is dependent on the degree of sweetening effect required by particular suspension, for example the sweetness level of adult and pediatric is not the same. The preferred amount of sugar sweetener should be between 40 to 100 gm per 100 mL of the suspension.

Artificial sweetening agents
Water soluble artificial sweeteners can also be added in place of sugar sweetener or in addition to them. The amount of artificial sweetening agents should be between 0 to 5 gms per 100 mL of suspension. Optimum taste-masking of Active pharmaceutical ingredients in the suspension can be obtained by limiting the amount of water in the suspension, but the amount of water must not be too low to hydrate MCC, Na CMC or other suitable suspending agent. The low amount of water should provide a sufficient aqueous base to impart desired degree of viscosity. The preferred total amount of water contained in the suspension should be between 30 to 55 grams per 100 mL of suspension.