Classification, Advantage And Disadvantage Of Pharmaceutical Elixir

Elixirs are sweetened hydro-alcoholic (water and alcohol) liquids for oral use. Typically, an elixir is composed of ethanol (3%–23%) and water which are used as solvents when the drug will not dissolve in water alone. In addition to active drugs, they usually contain flavouring and colouring agents to improve patient acceptance. In general, non-aqueous solvents (alcohol, glycerin or propylene glycol) form a significant proportion of the vehicle used in elixirs, or alternatively solubilising agents are included.

Elixir

Elixirs contain at least one active ingredient. It is a liquid drug that usually contains either potent or unpleasant-tasting drugs. The formulation is clear and generally contains a high proportion of sugar or other sweetening agent, included to mask offensive or nauseating tastes. Paediatric elixirs are usually formulated with a fruit syrup as a base flavouring agent.

Compared to syrups, elixirs are less viscous due to the minimal inclusion of sugar components and viscosity enhancers. Moreover, elixirs are mostly composed of liquid constituents, with small quantities of excipients having to be dissolved. Thus compared to syrups, they are more readily prepared. Nonetheless, due to their alcoholic content, drug and excipients’ incompatibilities along with age restrictions should be considered carefully.

Preparation Of Elixirs

Elixirs are usually prepared by simple solution with agitation and/or by admixture of two or more liquid ingredients. They are used either as vehicles or for the therapeutic effect of the medicinal substances that they contain.

Alcohol soluble and water-soluble components are generally dissolved separately in alcohol and in purified water, respectively. Then the aqueous solution is added to the alcoholic solution, rather than the reverse, to maintain the highest possible alcoholic strength at all times so that minimal separation of the alcohol soluble components occurs.

Frequently, the final mixture will be cloudy, principally because of separation of some of the flavoring oils by the reduced alcoholic concentration. If this occurs, the elixir is usually permitted to stand for a prescribed number of hours to ensure saturation of the hydroalcoholic solvent and to permit the oil globules to coalesce so that they may be more easily removed by filtration.

Talc, a frequent filter aid in the preparation of elixirs, absorbs the excessive amounts of oils and therefore assists in their removal from the solution. The presence of glycerin, syrup, sorbitol, and propylene glycol in elixirs generally contributes to the solvent effect of the hydroalcoholic vehicle, assists in the dissolution of the solute, and enhances the stability of the preparation. However, the presence of these materials adds to the viscosity of the elixir and slows the rate of filtration.

Sucrose increases viscosity but decreases the solubility properties of water and so must be added after primary solution has been carried out.

Classification Of Elixirs

Elixirs are divided into two categories: non-medicated elixirs and medicated elixirs.

Non Medicated Elixirs

These are used as solvents or vehicles for the preparation of medicated elixirs. They don't contain therapeutic agents. May only contain alcohol, sweetening agents and colouring agents. They are self preserved. Active ingredients are dissolved in a 15–⁠50% by volume solution of ethyl alcohol. Those containing approximately 25 percent alcohol are simple elixir, Iso-alcoholic elixir or low alcohol elixir. Those containing 8-10% alcohol are high alcoholic elixir. Finally, elixirs with 75-78% alcohol are aromatic elixir and iso alcoholic elixir. Then we have 1compound benzaldehyde elixirs (NF).

Non Medicated elixirs may be useful to the pharmacist in the extemporaneous filling of prescriptions involving:

• The addition of a therapeutic agent to a pleasant-tasting vehicle and

• Dilution of an existing medicated elixir

Medicated Elixirs

Medicated elixirs are solutions of active ingredients dissolved in water and alcohol along with other excipients such as preservatives. Medicated elixirs are employed for the therapeutic benefit of the medicinal agent. Most official and commercial elixirs contain a single therapeutic agent. The main advantage of having only a single therapeutic agent is that the dosage of that single drug may be increased or decreased by simply taking more or less of the elixir, whereas when two or more therapeutic agents are present in the same preparation, it is impossible to increase or decrease the dose of one without an automatic and corresponding adjustment in the dose of the other, which may not be desired.

Examples include;

1. antihistaminic elixirs used against allergy, such as chlorpheniramine maleate (USP) or diphenhydramine HCl

2. sedative and hypnotic elixirs, the former to induce drowsiness, the latter to induce sleep

3. pediatric elixirs such as chloral hydrate expectorant elixirs used to facilitate productive cough (i.e. cough with sputum), such as terpin hydrate

Advantages Of Elixir

1. Elixirs are more fluid than syrups

2. It often is desirable

3.it is more effective in masking such tastes

4. Elixirs are more readily prepared and manufactured than syrups

5. An elixir may contain both water and alcohol soluble ingredients

6. Insoluble drug compounds can be incorporated into the hydroalcoholic vehicle

7. Drug concentrates can be prepared in high-alcohol-containing elixirs

8. Hydroalcoholic vehicles can be self-preserving

9. Elixirs are less viscous and contain a lower proportion of sugar

Disadvantage Of Elixir

1. Alcohol is not good for children patients on antidepressant medication

2. Because they contain volatile materials, it must be stored in a watertight screw-top jar and away from sources of ignition

3. Water-insoluble drug compounds may precipitate due to alcohol evaporation

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