Surfactants in Drug Delivery and Industry
Explore the role of surfactants in drug delivery, their types, properties, and applications in various industries. Learn how surfactants enhance drug solubility, control release, and minimize toxicity, while also serving as emulsifiers and stabilizers in industrial settings.
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Presentation Transcript
Surfactants Kausar Ahmad http://staff.iium.edu.my/akausar akausar@iium.edu.my Physical Pharmacy 2 1
Contents Role of surfactants Types of surfactants Non-ionic surfactants HLB concept Effect of structure Stability of polyoxyethylene chain Natural surfactants Physical Pharmacy 2 2
POP QUIZ! Name ONE surfactant Physical Pharmacy 2 3
ROLE OF SURFACTANTS IN DRUG DELIVERY Enhance effective drug solubility Increase therapeutic efficiency Control of drug release Facilitate control of drug uptake Minimise drug degradation Contribute to reduced drug toxicity Physical Pharmacy 2 4
WHAT ARE SURFACTANTS? Emulsifier, Dispersant, Wetting agent, Stabiliser Common application: cleaning dirty clothes and kitchenware, writing on paper with a pen, greasing of cooking surfaces Surfactants in industry: emulsion polymerisation, paper coating food, pharmaceuticals, cosmetics Physical Pharmacy 2 5
PROPERTIES OF SURFACTANTS Adsorb at miscellaneous interfaces Changes interfacial tension wettability, foaming property, dispersibility Sufficient effect can be seen at 0.05% - 0.5% w/w or up to the c.m.c. in water depending on the surfactant system Physical Pharmacy 2 6
Example: EFFECT OF SURFACTANT CONCENTRATION ON O/W EMULSION Particle size decreases Stability increases Less creaming Less coalescence Physical Pharmacy 2 7
Example: EFFECT OF SURFACTANT CONCENTRATION ON DISPERSION Particle size decreases Stability increases Less sedimentation Less caking Less coagulation/aggregation Physical Pharmacy 2 8
TYPES OF SURFACTANTS Molecule consists of a hydrophobic group and a hydrophilic group; MW >200 hydrophilic groups: anionic cationic amphoteric nonionic Physical Pharmacy 2 9
TYPICAL HYDROPHILIC GROUPS Anionic Cationic quarternary ammonium salts N+(CH3)3Cl- carboxylates: -COO- sulfonates: -SO3- sulfates: -OSO3- phosphates: -OPO32- Amphoteric Nonionic betaine: - N+(CH3)2CH2COO- polyoxyethylene group Physical Pharmacy 2 10
POP QUIZ What is the problem with ionic surfactants? Physical Pharmacy 2 11
Typical hydrophobic groups Hydrocarbon Most popular group contains 8 to 22 carbon atoms 1) oils & fats: triglycerides, fatty acid, fatty alcohol 2) petroleum & petrochemicals: n-paraffin, alkylbenzene, synthetic alcohol Fluorocarbon fluorated fatty acid and alcohol Organosilicone polysiloxanes Physical Pharmacy 2 12
Structure of hydrophobic groups Linear Branched Aromatic Cyclic Physical Pharmacy 2 13
Cationic surfactant e.g. Bactericides Medicine Dosage Bactericide Base benzalkonium chloride Skin disease 0.20 mg 1 g benzalkonium Eye lotion 0.05 mg 1 g benzalkonium + R2 1 ml Nasal congestion 1 mg benzalkonium N R1 R3 X- R4 10 mg Wounds benzetonium 10 g Oral hygiene 40 mg benzetonium 1 ml Physical Pharmacy 2 14
HYDROPHILE-LIPOPHILE BALANCE The HLB is an important criterion for the selection of an emulsifier in determining oil-in-water (O/W) or water-in-oil (W/O) emulsion Oil Phase Required HLB Number W/O 6-9 ? ? 8 O/W 12.5 7-9 14-16 15 Kerosene Palm oil Camphor oil Lanolin Physical Pharmacy 2 15
Required HLB in Products Application HLB Surfactant (%) Emulsion paint 14 - 16 1 - 2 Ointment for penicillin 8 10 Suppository 10 90 Ointment containing sulfur 5 0.25 Household detergent 13 15 Shampoo 14 - 15 2 - 10 Physical Pharmacy 2 16
Phase Inversion Temperature (PIT) Temperature at which Possible because of changes in the solubility of nonionic surfactant as a function of temperature O/W emulsion changes to W/O emulsion Hydration power of hydrophilic group decreases as temperature increases Destroying ether linkage Entropy consideration Free movement of water molecules Physical Pharmacy 2 17
NATURAL SURFACTANTS Plant extracts: leaves, seeds, stems Proteins Lanolin Eggs E.g. Entana spiralis (locally known as beluru/sintok) e.g. milk casein w/o emulsifier Physical Pharmacy 2 18
REFERENCES Martin Malmsten, Surfactants and Polymers in Drug Delivery, Marcel Dekker (2002) Chapter 1 F Nielloud & G Marti-Mestres, Pharmaceutical Emulsions and Suspensions, Marcel Dekker, New York (2000) Chapter 1 ME Aulton, Pharmaceutics: The Science of Dosage Form Design, Churchill Livingstone (1988) Chapter 4 DM Collett & ME Aulton, Pharmaceutical Practice, Churchill Livingstine (1990) Chapter 13 Protein-based surfactants, Marcel Dekker, New York (2001) Physical Pharmacy 2 19
