Excipient reducing agents

Reducing agents These have a lower redox potential than the drug or excipient they are protecting Ascorbic acid... 

One of the critical factors in excipient selection and concentration is the effect on preferential hydration of the biopharmaceutical product [53, 54], Preferential hydration refers to the hydration layers on the outer surface of the protein and can be utilized to thermodynamically explain both stability enhancement and denatur-ation. Typical excipients used in protein formulations include albumin, amino acids, carbohydrates, chelating and reducing agents, cyclodextrins, polyhydric alcohols, polyethylene glycol, salts, and surfactants. Several of these excipients increase the preferential hydration of the protein and thus enhance its stability. Cosolvents need to be added in a concentration that will ensure their exclusion from the protein surface and enhance stability [54], A more comprehensive review of excipients utilized for biopharmaceutical drug products is available elsewhere [48],... 

Reducing agents these have a lower redox potential than the active substance or excipient they are protecting. The agent (e.g. sodium metabisulfite, sodium formaldehyde-sulfoxylate, ascorbic acid) is oxidised more easily than the active substance. 

Mouthwashes are aqueous concentrated solutions containing one or more active ingredients and excipients. They are used by swishing the liquid in the oral cavity. Approximately 15-30 ml. of mouthwash are used for single mouthful of rinse for about a minute. Mouthwashes can be used for therapeutic and cosmetic purpose. Therapeutic mouthwashes are used to reduce plaque, dental caries, gingivitis and stomatitis while cosmetic mouthwashes are used to reduce bad breath and it contains used antimicrobial and/or flavoring agent. Mouthwashes other than used for cosmetic purpose, should only be used under the direction of physician/dentist since it contains certain medicines. 

Tonicity agents are added to injectable preparations to prevent osmotic shock at the site of injection upon administration, and thereby reduce local irritation. Typical excipients used for tonicity adjustment include saline, glycerin, mannitol, dextrose, and trehalose. Tonicity is a colligative property that depends primarily on the number of dissolved particles in solution. Hence, the amount of tonicity agent to be added depends on the specific formulation. Typically, osmolality of 280 to 320mOsm is considered iso-osmotic. 

An alternative approach is to reduce the rate of mucociliary clearance and hence increase the retention time of the drug. This can be achieved by including an excipient in the formulation with a reversible ciliostatic effect such agents include certain preservatives. However, it is important that the chosen strategy does not permanently compromise mucociliary clearance, which would adversely affect airway homeostasis and defense. 

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