PREPARATION OF SOLUTIONSBy

Dr. Muhammad Ameen

PREPARATION OF SOLUTIONSINTRODUCTION:•Solutions are Dosage forms prepared by dissolving the

active ingredient(s) in an aqueous or non aqueous solvent.

OR

•Solutions are prepared from any combination of solids, liquid and the gas, the three states of matter results in the formation of homogenized single phase mixture.

e.g., syrups, elixirs, spirits and tinctures.

ADVANTAGES OF SOLUTION•Easier to swallow therefore easier for:

children - old age - unconscious people.

• More quickly effective than tablets and capsules.

• Homogenous therefore give uniform dose than suspension or emulsion which need shaking.

DISADVANTAGES OF SOLUTION• Less stable than solid dosage forms.

•Need special storage conditions.

•Harder to measure accuracy.

•Unpleasant taste or odours are difficult to mask.

Classification of Solutions According to Vehicle

a) Aqueous solutionsb) Non-aqueous solutions

•Aqueous Solutions

• Aqueous solutions are those that are prepared by dissolving a solid, liquid or gas in an aqueous medium (vehicle).

• Vehicle: This may be water, aromatic water or extracts.

Non Aqueous Solutions

• The solutions obtained by dissolving a solute in any solvent other than water are called non aqueous solutions (non aqueous means without water).

• Vehicle: This may be benzene, alcohol, ether, carbon disulphide.

Classification of solution according to the route of administration•Oral solution•Otic solutions•Ophthalmic solutions•Topical solution

PRESERVATION OF SOLUTION• Solution may contaminated for number of reasons.• Raw materials used in the manufacture of solution may cause

contamination in it, such as gums, stabilizers, sugars and flavors.

• Due to the presence of water, the growth of microorganism and fungi increases.

• So preservatives should be used which are:1.effective against a wide spectrum of microorganisms 2.stable for its shelf life 3.non toxic, non sensitizing 4.compatible with the ingredients in the dosage form 5.free of taste and odour• Examples: benzoic acid(0.1%), sodium benzoate(0.1-0.2%)

FLAVOURING AGENTS•Flavouring agents are added to increase patient

acceptance.•Flavours used to mask the bitter taste of drug.•EXAMPLES: volatile oils (orange oil),clove oil, citric

acid, glycerin, menthol and vanillin etc.•These flavorings must be water soluble.

COLORING AGENTS•Coloring agents used to impart the preferred color to

the formulation.•The colorants should be water soluble, nonreactive

with the other syrup components and the colour stable under the PH range.

•There are two types of coloring agents:•Natural •Synthetic•For example: mint(green), chocolate(brown)

SWEETENING AGENTS•Sweetening agents employed in liquid formulations

to increase the palatability of the therapeutic agents and to mask the unpleasant taste of the drug.

•EXAMPLES: sucrose, sorbitol, glucose and glycerin etc.

STABILIZERS•A range of chemical stabilizers are used to prevent

chemical reactions between chemicals and improve the chemical stability of the drug.

•These include;•Antioxidants – ascorbic acid (0.2% w/v) and sodium

metabisulfate (0.1% w/v)•Chelators- Ethylene diamine tetra-acetic acid (EDTA)