Explain Biphasic liquid dosage form
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Answer:
BIPHASIC LIQUID DOSAGE FORMS
Additives used in suspension dosage forms
1. Wetting agents: Some substances (e.g. sulfur, hydrocortisone etc.) are both insoluble in water and are poorly wetted by it. During preparation it is difficult to disperse the clumps and the foam produced on shaking. So wetting agents are used to reduce the interfacial tension between the solid particle and the vehicle and increase wetting of the particle.
e.g. alcohol, glycerin, propylene glycols, saponins of quillaia extract etc.
2. Flocculating agents: On standing for a long period the suspension may become difficult to redisperse on shaking. That time, controlled flocculation is required to prevent compact sediment, which is difficult to redisperse. Controlled flocculation can be produced either by,
(i) electrolytes (e.g. potassium citrate, phosphate salts), (ii) surfactants, and (iii) polymers.
3. Suspending agents / Thickening agents: Suspending agents are the substances, which are added to a suspension to increase the viscosity of the continuous phase so that the particles remain suspended for a sufficiently long time and it becomes easy to measure an accurate dose.
Due to increase in viscosity of the vehicle, the particles sediment at a much slower rate.
e.g. methylcellulose, hydroxy propyl methyl cellulose, sodium carboxymethylcellulose, bentonite, veegum etc.
4. Preservative: The aqueous vehicle may be liable for bacterial growth, so a preservative should be used. e.g. benzoic acid, sodium benzoate, methylparaben, proptlparaben etc. may be used.
5. Organoleptic additives: Colors, sweeteners and flavoring agents may be used to make the oral suspensions more palatable.
Colors: e.g. Amaranth, Tartrazine, Caramel, and other approved colors
Sweeteners: e.g. Sucrose
Flavors: e.g. Peppermint oil, Chocolate flavor, Raspberry syrup etc.
Explanation: