1. PRINCIPLES OF COMPOUNDING Terrick Andey College of Pharmacy & Pharmaceutical Sciences Florida A&M University February 2013

2. SUSPENSIONS Definition: a two phase system consisting of a coarse dispersion finely divided insoluble solids dispersed in a liquid Suspensions may be classified as: – Suspensions – Mixtures – Magmas – Gels – lotions

3. SUSPENSIONS - Stability Two stability issues for suspensions are: – Caking – Crystallization Caking is prevented by the use of flocculating agents Crystallization is attenuated by the use of viscosity enhancers Wetting agents are used to enhance the uniform dispersion of powders

4. SUSPENSIONS – Flocculating agents Flocculating agents: electrolytes with an opposite charge to the net charge of the suspended particles Flocculating agents facilitate the formation of floccules which are easily dispersible and prevent caking Examples: KCl and NaCl

5. SUSPENSIONS – Viscosity enhancers Viscosity enhancers: also known as thickening agents or suspending agents Thickens the dispersion medium thus, retarding the rate of sedimentation Examples: acacia, agar, bentonite, gelatin, carboxymethylcellulose, pectin, tragacanth, sodium alginate

6. SUSPENSIONS – Wetting agents Powders to be incorporated into suspensions must be wetted first Wetting ensures uniform dispersion of particles in the dispersion medium Powders can be hydrophilic or hydrophobic Hydrophilic powders can be wetted with water or other polar substances (e.g. alcohol, glycerin) – Examples: ZnO, MgCO 3 Hydrophobic powders can be wetted glycerin, alcohol, or other organic solvents (e.g. mineral oil) – Examples: Sulphur, Charcoal

7. SUSPENSIONS Suspension: these are dispersion of solids in a liquid for oral administration These are usually flavored or sweetened to enhance compliance

8. LOTIONS Definition: liquid suspensions or dispersions intended for external application to the body Extemporaneous preparation involves the trituration of ingredients to a smooth paste and incorporation of remaining liquid phase Example: Calamine Lotion

9. LOTIONS – Calamine lotion Calamine Lotion R x : Calamine8 % Zinc Oxide8 % Glycerin2 % Bentonite Magma25 % Calcium Hydroxide q.s. ad to 90 ml Procedure: 1.Dilute Bentonite Magma in a beaker with an equal volume of Calcium Hyrdoxide solution. 2.Mix the powder intimately in a glass mortar with the glycerin and about 9 ml of the diluted Bentonite Magma. 3.Triturate the mixture until a smooth paste is formed. 4.Gradually incorporate the remainder of the diluted Bentonite Magma. 5.Transfer the mixture into a three ounce bottle. 6.Add enough Calcium Hydroxide Solution to make 90 ml, and shake well.

10. THE END