Liquid dosage forms, (Emulsion & Suspension)

Liquid dosage forms.Unit-3
Helpful for students of Bachelor of Pharmacy, First semester, Pharmaceutics.AKTU, LUCKNOW

1. LIQUID DOSAGE FORMS Ruchi Pal Assistant Professor Maa Bhagwati College Of Pharmacy, Lucknow .

2. CONTENT Introduction Advantages & Disadvantages Pharmaceutical Additives used in liquid dosage form Classification of Liquid dosages forms Monophasic liquid dosage forms Biphasic liquid dosage forms Pharmaceutical Emulsion Introduction Classification Uses Advantages & Disadvantages Methods of preparation Pharmaceutical Suspension Introduction Advantages & Disadvantages Classification Flocculated & Deflocculated suspension Evaluation of suspension

3. LIQUID DOSAGE FORM Liquid dosage form are liquid in nature & are meant for internal, external or simple meant to insert into body cavities. For example-Solution, Syrup, Elixir, Suspension.

4. Syrup : A viscous oral liquid that contains one or more active ingredients in solution. The base generally contains large amounts of sucrose, other sugars, or sweetening agents. Syrups may contain ethanol (95%) as a preservative or as a solvent for flavors. Antimicrobial agents may also be added to syrups to maintain the microbial quality of preparation . Oral Suspension : an oral liquid that contains one or more active ingredients suspended in a suitable base . Oral Solution : an oral liquid that contains one or more active ingredients dissolved in a suitable base . Oral Drop : an oral liquid that is prepared to take in small quantity with the help of a suitable measuring device such as a dropper . Oral Emulsion : an oral liquid that contains one or more active ingredients that are unstable in the water phase and is stabilized oil-in-water dispersions; either or both phases of the preparation may contain dissolved solids . Mixtures : an oral liquid containing one or more active ingredients suspended or dispersed in a suitable base . Linctus : a viscous oral liquid that contains one or more active ingredients dissolved in a suitable base that generally contains a higher concentration of sucrose or other sugars. Elixir : a clear, flavored oral liquid containing one or more active ingredients dissolved in a suitable base that contains a high proportion of sucrose and may also contain ethanol (95%) or a diluted ethanol.

5. Advantages of liquid dosage form- Most convenient dosage form for infants and childrens. Possible to formulate drugs with bitter odour & taste in liquid dosage form by addition of sweetning & flavouring agent. Adjustment of dose as per the requirment, need & nature of patient is possible. Liquid dosage form have good absorption as compared to solids. Disadvantages of liquid dosage form- They are difficult to handle, carry, store and transport. Liquid dosage form containing alcohol as vehicle in various cup syrup, & may account to severe toxicity when administered in children. Accuracy of dose is major issue in case of liquid dosage form. Two incompatible drug cannot be formulated as liquid dosage forms.

6. Pharmaceutical Additives/Excipients used in liquid dosage form

7. Antioxidants -Vitamin A,C, E, Beta carotene, Lutein, Lycopene Solvents - Water, Polyhydric alcohol, Hydro-alcoholic solution etc. Surfactants - SLS, Tween, Span Preservatives - Benzoic acid, Potassium Nitrate, Sodium Benzoate Coloring agents - Turmeric, Safaranin . Flavouring agents- Lemon, Mango, Strawberry. Sweetning agents - Glucose, Sucrose, Saccharin. Solubilizing agents - Glycerine .

8. Methods of S olubility Enhancement Solubility- The ability to be dissolved, especially in water. The maximum amount of a substance that will dissolve in a given amount of solvent at a specified temperature. METHODS- Particle size reduction Surfactant PH adjustment Salt formation Solid dispersion

9. Emulsifying agent(Emulsifier) The emulsifying agent is a surface-active substance to make an emulsion, which is both fat and water-soluble. It helps the dispersed phase to uniformly dispersed in the continuous phase . Examples of Emulsifying agent(Emulsifier ): Natural Emulsifying Agents:  Acacia, Tragacanth, etc . Synthetic Emulsifying Agents:  Polysorbate 20, Polysorbate 80, Sodium lauryl sulfate(SLS), Sorbitan laurate, Sorbitan stearate, etc.

10. Pharmaceutical Emulsion An emulsion is a two phase system consisting of two completely immiscible liquids one of which is dispersed as fine globules into other. This thermodynamically unstable system is stabilised by presence of emulsifying agents. There are two phases in an emulsion. One is the dispersed phase and another is the continuous phase. The concept is a dispersed phase (liquid), which is dispersed or spread in the other phase(continuous phase ). Examples of emulsions:  Milk (fat in water), Butter (water in oil), Liquid paraffin (paraffin in water), etc.

11. Advantages- Cover up the unpleasant taste. Increase the bioavailability of the dose. Sustained release medication. Very cost-effective. Disadvantages- Problem of creaming and sedimentation Phase inversion problem of handling.

12. Method of Preparation of Emulsion

13. Stability of Emulsion

14. Uses of Emulsion Pharmaceutical Application:  Due to the high bioavailability and absorption rate, it used in the pharmaceutical industry. Mostly it used for topical preparations like creams, lotions, etc. Cosmetic industry:  There is a huge application of emulsion in the cosmetic industry. Example: creams, lotions, hair conditioners, etc. Food industry:  Food products like milk, peanut butter, ice cream, etc. are some examples of emulsion. So you can easily understand the application of emulsion in this industry. Paint industry:  Examples like emulsion paints and inks.

15. Pharmaceutical Suspension The pharmaceutical suspension is  a biphasic liquid or semi-solid dosage form where the finely divided insoluble solid drug particles are homogeneously dispersed in a liquid or semi-solid medium . The insoluble solid drug particles act as the dispersed phase or internal phase . Properties of Suspension A suspension is a heterogeneous mixture. The size of solute particles in a suspension is quite large. The particles of a suspension can be seen easily. The particles of a suspension do not pass through a filter paper. So a suspension can be separated by filtration. The suspension is unstable. The particles of a suspension settle down after some time. A suspension scatters a beam of light passing through it because of its large particle size .

16. Examples of Suspension Muddy water Milk of magnesia- Milk of magnesia is  the common name for magnesium hydroxide, which is a type of saline laxative . It's recommended for occasional constipation. You can expect to have a bowel movement within 6 hours of taking milk of magnesia . Sand particles suspended in water Flour in water Slaked lime for whitewashing Paints in which dyes are suspended in turpentine oil.

17. Classification of Pharmaceutical Suspensions

18. Oral Suspension

19. Externally applied suspension

20. Parenteral Suspension

21. Rectal suspension

22. Flocculated & Non-flocculated Suspension

23. Evaluation of Stability of Suspension Prepared suspension were evaluated by studying different parameters like pH, sedimentation volume, redispersibility, Flow rate (F), viscosity, Degree of flocculation- A most important parameter in the evaluation stability of the suspension. Sedimentation volume is a ratio of the ultimate volume of sediment (Vu) to the original volume of sediment (VO) before settling. The sedimentation volume gives only a qualitative account of flocculation . effect of temperature etc.

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