Solvents for Liquid Preparations PDF

Some Solvents used for Liquid Preparations 1. Purified Water, USP 2. Alcohol, USP: Ethyl Alcohol, Ethanol 3. Diluted Alcohol, NF 4. Rubbing Alcohol 5. Glycerin, USP (Glycerol) 6. Isopropyl Rubbing Alcohol 7. Propylene Glycol, USP  (1) Purified Water, USP...

Some Solvents used for Liquid Preparations 1. Purified Water, USP 2. Alcohol, USP: Ethyl Alcohol, Ethanol 3. Diluted Alcohol, NF 4. Rubbing Alcohol 5. Glycerin, USP (Glycerol) 6. Isopropyl Rubbing Alcohol 7. Propylene Glycol, USP  (1) Purified Water, USP Purified Water, USP, is obtained by distillation, ion exchange, reverse osmosis, or other suitable process. It is prepared from water complying with the federal Environmental Protection Agency with respect to drinking water. Purified water, USP, has fewer solid impurities than ordinary drinking water. It is intended for use in preparation of aqueous dosage forms except those intended for parenteral administration (injections). (2) Alcohol, USP: Ethyl Alcohol, Ethanol Alcohol is the most useful solvent in pharmacy next to water. Alcohol USP is 94.9 to 96% C2H5OH by volume (i.e., v/v) Together with water it forms a hydro alcoholic mixture that dissolves both alcohol-soluble and water-soluble substances, a feature especially useful in the extraction of active constituents from crude drugs.  Certain drugs are insoluble in water and must be dissolved in an alternative vehicle. So, alcohol is used widely as a solvent and excipient in oral pharmaceutical products. Alcohol is frequently used with other solvents, such as glycols and glycerin, to reduce the amount of alcohol required in different liquid dosage forms. It also is used in liquid products as an antimicrobial preservative alone or with parabens, benzoates, sorbates, and other agents. However, concern has been expressed over the undesired pharmacologic and potential toxic effects of alcohol.  Amount of Alcohol USP in OTC products hildren under 6 years of age alcohol limit 0.5% 6-12 years of age 5% Over 12 years of age and adults 10%  (3) Diluted Alcohol, NF Diluted Alcohol, NF, is prepared by mixing equal volumes of Alcohol, USP, and Purified Water, USP. The strength of Diluted Alcohol, NF, is not exactly half that of the more concentrated alcohol but slightly lesser, approximately 49%. Diluted alcohol is a useful hydro alcoholic solvent in various pharmaceutical processes and preparations.  (4) Rubbing Alcohol Rubbing alcohol (synonym: alcohol rubbing compound) contains about 70% ethyl alcohol by volume, the remainder consisting of water, denaturants with or without color additives and perfume oils and stabilizers. It is employed as a rubefacient externally for bedridden patients, a germicide for instruments, and a skin cleanser prior to injection. It also used as a vehicle for topical preparations. The product is volatile and flammable and should be stored in tight containers away from fire.  (5) Isopropyl Rubbing Alcohol Isopropyl rubbing alcohol is about 70% by volume isopropyl alcohol, the remainder consisting Commercially of water with or without 91% isopropyl alcohol color additives, Solution is used stabilizers, and perfume for diabetic patients oils. disinfecting needles, It is used externally as a syringes and skin rubefacient and soothing rub and as a vehicle for topical products.  (6) Glycerin, USP (Glycerol) Glycerin is a clear syrupy liquid with a sweet taste. It is miscible with both water and alcohol. Glycerin has preservative qualities and is often used as a stabilizer and as an auxiliary solvent in combination with water or alcohol. It is used in many internal and external preparations.  (7) Propylene Glycol, USP Propylene glycol, a viscous liquid, is miscible with water and alcohol. It is a useful solvent with a wide range of applications and is frequently substituted for glycerin in modern pharmaceutical formulations.