Elixirs are clear, liquid, flavored hydroalcoholic preparation intended for oral use. They contain one or more medicaments, pleasantly flavored, usually attractive color containing high proportion of alcohol or sucrose or suitable polyhydric alcohols together with suitable additives (including antimicrobial agents). The alcoholic contents in elixir vary from 5% to 40%. In general they are more stable than mixture as sufficient alcohol is added to maintain the drug in solution. Most of the elixirs become turbid when moderately diluted by aqueous fluids.
Elixirs are mainly of two types
1. Non-medicated elixir:
They are used purely as diluting agents or solvents for drugs containing approximately 25 percent alcohol, e.g., simple elixir, Iso-alcoholic elixir or low alcohol elixir (containing 8-10% alcohol), High alcoholic elixir (containing 75-78% alcohol)
ADVERTISEMENTS:
2. Medicated elixirs:
Elixirs containing therapeutically active compounds are known as medicated elixirs, e.g., Phenobarbital elixir USP, Dexamethasone elixir USP, Chlorpheniramine Maleate elixir USP, Diphenhydramine Hydrochloride elixir USP, Piprazine Citrate elixir, Terpin Hydrate elixir etc.
The elixir is used as a vehicle for other drugs in many commercially available cough syrups viz. dextromethorphan hydrobromide, codeine phosphate, pyrilamine maleate, ammonium chloride, creosote, chloroform, and a wide variety of other drugs with expectorant and antitussive properties.
Some proprietary elixirs (phenethicillin and phenoxymethyl penicillin) are available in the market in granule or powder form because active ingredients are unstable in solution. They are dispersed by adding measured amount of water or at a specified point in bottle and shaken until solution is complete. The preparation is labeled so as to be stored in cool place and used within one week.
ADVERTISEMENTS:
Formulation
Generally elixirs contain following ingredients.
Vehicles:
About 10% to 20% of alcohol is used for keeping oils, vegetable extracts, tannin etc., in solution form. Faint opalescence from flavoring agents containing essential oils and light precipitants from vegetable extracts are not considered acceptable in elixirs. Glycerol and propylene glycol are used as solvents.
ADVERTISEMENTS:
Stabilizers:
In neomycin elixir, citric acid is used to adjust pH 4.0 to 5.0 to minimize the darkening that occurs on storage. Disodium edetate should be used to sequester heavy metals that catalyse decomposition of the antibiotics.
Flavouring agents:
Sweetening agents and fruit flavors are used in many medicinal preparations e.g., Black currant syrup in chloral elixir, Concentrated raspberry juice with inverted syrup in paracetamol elixir, Lemon spirit with invert syrup in ephedrine elixir, compound orange spirits with glycerol in phenobarbital elixir.
ADVERTISEMENTS:
Preservatives:
In elixir, fermentation and mold growth are inhibited when it contains more than 20% of alcohol, propylene glycol or glycerol. Syrup containing saturated solution of sucrose is also inhibitory to many microorganisms because of high osmotic pressure. The commonly used preservatives are double strength chloroform, spirit, and benzoic acid and methyl ester of p- hydroxy benzoic acid.
Method of Preparation
Elixirs are prepared by dissolving the ingredients with agitation / or by admixture of two or more liquid components in the suitable solvent. Usually, the alcohol soluble substances are dissolved in alcohol and water soluble in water separately. As a rule, the aqueous solution is always added to alcoholic solution.
ADVERTISEMENTS:
The aqueous solution is then added to the alcoholic solution with constant stirring and make up the volume with the solvent or vehicle specified in the formulation. At this stage the product may not be clear due to the separation of some of the flavouring agents because the alcoholic strength is reduced. In such case the elixir is allowed to stand for some time to ensure the saturation of the hydroalcoholic solvent and permit the oil globules to coalesce. Talc (upto 3%) can be used to absorb the excess of oils and assist in their removal from solution. Filtration gives a bright clear product.
Container
It should be dispensed in narrow mouthed, screw capped, colorless plain bottle.
Example 01: Prepare and Dispense Low Alcohol Elixir
ADVERTISEMENTS:
Compound orange spirit 1.0 ml
Alcohol 10.0 ml
Glycerin 20.0 ml
Sucrose 32.0 ml
Purified water, sufficient to produce 100.0 ml
Method of Dispensing:
Mix the alcohol, glycerin and 50.0 ml of purified water and add measured amount of compound orange spirit with agitation. Allow to stand for 24 hours, Filter this solvent mixture through filter papers and dissolve the weighed amount of sucrose in the filtrate by agitation or percolation and finally add the solvent mixture to make volume to1OO ml.
Method of Dispensing:
Dissolve the compound orange spirit and the saccharin in 70.0 ml of alcohol and add glycerin. Add sufficient amount of alcohol to produce 100.0 ml and mix properly. Filter the mixture and preserve in suitable container.
Example 03: Prepare and dispense simple elixir
Orange tincture
Syrup
Chloroform water, sufficient to produce
Method of Dispensing:
Mix orange tincture with the syrup and add sufficient chloroform water to produce 100.0 ml. Add 5% of purified talc and shake vigorously. Filter the elixir and preserve in a suitable container.
Example 04: Prepare and dispense Paediatric Paracetamol Elixir
Paracetamol : 2.4 ml
Ethanol (96%) :10.0ml
Propylene glycol :10.0ml
Concentrated raspberry juice :2.5 ml
Chloroform spirit : 2.0 ml
Invert syrup : 27.5 ml
Amaranth solution : 0.2 ml
Glycerin, sufficient to produce : 100.0 ml
Method of Dispensing:
Mix ethanol (96%), propylene glycol and chloroform spirit and make a mixture. Dissolve paracetamol and shake it, add other additives and sufficient amount of glycerin to produce 100 ml.