Surfactants Formulations Kausar Ahmad Kulliyyah of Pharmacy IIUM

Surfactants & Formulations Kausar Ahmad Kulliyyah of Pharmacy, IIUM Physical Pharmacy 2 1

Choice of surfactants 1. 2. 3. 4. l l HLB PIT H/L numbering Water absorbing method Applicable for simple phase emulsions but not for complex phase materials. Normally based on trial and error Physical Pharmacy 2 2

Characteristics of Emulsifiers l Combination of anionic and nonionic to give excellent emulsion stability and viscosity control l Examples of nonionic fatty acid monoglycerides, sorbitan fatty acid esters, sugar esters, derivatives of polyoxyethylene fatty alcohol ethers/fatty acid esters/sorbitan fatty acid esters/hydrogenated castor oil l Examples of anionic fatty acid soaps, fatty alcohol sulfates Physical Pharmacy 2 3

Surfactants Application Advantages Fatty acid monoglycerides w/o vanishing creams/lotions Not sticky, excellent thickening Sugar esters Cosmetic formulation Not efficient but complete safety POE fatty acid esters & hydrophobic Creams & milky lotions Great thickening BUT hydrolysis Fatty acid soaps creams & nonionic Excellent chemical stability, gloss and viscosity BUT alkaline Alkyl sulfate & nonionic Low foaming BUT skin irritation creams Physical Pharmacy 2 4

Surfactants in Cosmetics l Determine appearance, chemical & physical properties, usage and storage conditions l From soaps changed to nonionic surfactants – less toxic l Emulsifiers should satisfy the following: l No toxicity and skin irritation l Chemically and physically stable (expiry? ) l Surfactants should not affect other ingredients – too many ingredients! Physical Pharmacy 2 5

Formulation Examples of Creams and Ointments O/W COLD CREAM 1. Stearic acid 2. Liquid paraffin 3. Vaseline 4. Cetyl stearyl alcohol 5. POE polyol f. a. esters 6. 7. 8. 9. 10. Physical Pharmacy 2 Glycerine TEA Deionised water Methyl paraben perfume 6

Cosmetic Bases 1. 2. 3. 4. 5. 6. Fats and oils Waxes Hydrocarbons Fatty acids Alcohols esters l Requirement l Low toxicity and skin irritation l No harmful effect on dermophysiology l Physical and chemical stability l No propagation of bacteria Physical Pharmacy 2 7

Shampoos l Surfactants l Anionic POE alkyl ether sulfate l Amphoteric imidazoline (low iritant) l nonionic fatty acid alkalonamides l Requirement l Satisfactory cleansing power l Easy rinsing – no scum l Soft & good manageability l Luster l Low irritation to skin & eyes Physical Pharmacy 2 8

Additives for Shampoo l l Preservatives benzoic/salicylic acid Thickening agents cellulose Anti-oxidant BHT Ultraviolet rays absorbent benzophenone l l l Conditioning agent fats/oils, cationic surfactant Anti-dandruff agent selenium disulfide Opacifier mica, polystyrene Physical Pharmacy 2 9

Example of Shampoo Formulation Refer YOUR actual shampoo formulation! Physical Pharmacy 2 10

Cream Rinse and Conditioner l Primary ingredient is cationic surfactant ca. 1 -5% e. g. dialkyl dimethyl ammonium salt; the longer the alkyl chain, the greater the softening effect (thick conditioner? ) l E. g. of nonionic POE sorbitan fatty acid ester Physical Pharmacy 2 11

Ingredients other than surfactants l Fats & oils l Solvent and humectant l Thickener Physical Pharmacy 2 12

Dentrifices l Pastes blended suspension of liquid paste thickened with binders l Gels l Powders l Liquids Physical Pharmacy 2 13

Ingredients and Composition of Toothpaste Polishing agents: sodium metaphosphate 25 -60 Humectants: glycerine 10 -30 Foaming agent: sodium alkyl sulfate 0. 5 -2 Binder: carrageenan 0. 5 -2 Flavour: peppermint 0. 5 -3 Sweetener: sodium saccharine 0. 1 -1 Preservative Therapeutic agent: neem, gamat? water To 100% Physical Pharmacy 2 14

Surfactants in Toothpaste l Provide the expected foaming l Reduce surface tension l Penetrate and loosen surface deposits l Emulsify and suspend debris which toothpaste removes from surface of teeth l E. g sodium lauryl sulfate, sodium coconut monoglyceride sulfonate Physical Pharmacy 2 15

Exercise l Identify surfactants in l Hair shampoo l Mouth l wash What are their specific functions? Physical Pharmacy 2 16