Essential Fatty Acids and Emollients Quiz

Introduction to Cosmetic Formulation

• Cosmetic science is a multidisciplinary field that encompasses concepts and principles from different fields of science.
• Cosmetics are defined as substances or preparations intended to be placed in contact with external parts of the human body to clean, perfume, change appearance, correct body odors, protect, or keep them in good condition.

Cosmetic vs. Drug

• A cosmetic differs from a drug in its intended use, not by the ingredients or amount of active ingredients.
• Consumer perception also plays a role in distinguishing between cosmetics and drugs.

Terms in Cosmetic Formulation

• Cosmeceuticals: multi-function products containing bioactive ingredients, can be purchased as cosmetics and advertised to have specific benefits.
• Personal care products: products used for hair, body, and teeth, also referred to as toiletries.
• Hypoallergenic: products that claim to produce fewer allergic reactions, but do not guarantee zero allergic reactions.
• Cruelty-free: products that use alternative methods to animal experiments for safety testing, but do not necessarily mean vegan.
• Preservative-free: products that replace water with higher percentages of alcohol or have a pH that prevents microbial growth.

Emollients

• Emollients are used to replenish oils and lipids in the skin.
• Types of emollients: animal-based (e.g. stearic acid, palmitic acid), vegetable-based (e.g. coconut oil, palm-kernel oil), and petroleum-based (e.g. petrolatum, mineral oil).
• Long-chain alcohols are useful as emollients and emulsion stabilizers.
• Esters of fatty alcohols and fatty acids make excellent emollients.

Moisturizers

• Moisturizers add or retain moisture in the skin.
• Subclasses of moisturizers:
  • Humectants: hygroscopic, prevents drying of preparations (e.g. glycerin, sorbitol, urea, propylene glycol).
  • Emollients: replenish oils and lipids in the skin.
  • Occlusives: hydrophobic, keeps moisture in (e.g. petrolatum, mineral oil, paraffin, carnauba or candelilla waxes).
  • Enhancers of the Skin Barrier: skin rejuvenators, enhance barrier function of the skin (e.g. collagen, keratin, elastin).

Waxes and Thickeners

• Waxes: long chain FA, solid at room temperature, has sealing properties (e.g. beeswax).
• Thickeners:
  • Cellulose: swells in hot water.
  • Carbopol: swells when neutralized.
  • Bentonite Clays: swells.
  • Carrageenan: used in foods, usually employed in gels.
  • Pectin: usually employed in gels.
  • Locust Bean: for flavoring.

Active Ingredients

• Acts physiologically to lighten, tighten, and firm the skin.
• Examples:
  • Fruit Acids (e.g. alpha-hydroxy acids).
  • Aluminum Chlorohydrate: employed as an antiperspirant.
  • Salicylic Acid: used for acne-prone skin.
  • Benzoyl Peroxide: used for acne-prone skin.
  • Dimethicone: skin protectant.
  • Petrolatum: skin protectant.

Pigments and Dyes

• Pigments: incorporated to impart color.
• Examples:
  • Face Powders: blending inorganic oxides with fillers.
  • Fillers: inert, inexpensive materials (e.g. kaolin, talc, silica, mica).
  • Eye shadows, Blushers, and Lipsticks: oils, zinc stereate.
  • Pearlescent Pigments: formed by precipitating a thin layer of color on thin platelets of mica.
  • Organic Pigments: lacks precipitating salt.

Preservatives and Antioxidants

• Preservatives: prevent microbial contamination and rancidity.
• Examples:
  • Parabens.
  • Phenoxyethanol.
• Antioxidants: prevent formations of free radicals in the skin.
• Examples:
  • Vitamin E (alpha-tocopherol).
  • Butylated hydroxytoluene (BHT).

Other Additives

• pH Buffers: to match the formulation's pH with that of the application surface.
• Examples:
  • Citric acid.
  • Lactic acid.
  • Sodium hydroxide.
  • Triethanolamine.
• Plasticizers: added to films to soften and impart flexibility.
• Examples:
  • Camphor.
  • Castor oil.
  • Glycerin tribenzoate.
• Propellants: added to aerosol preparations to maintain pressure and help expel contents.
• Examples:
  • Isopentane (liquified gas).
  • Butane.
  • Sobutane.
  • Propane.

Solvents

• Polar solvents: water, glycerin, propylene glycol.
• Semi-polar solvents: ethanol, isopropyl alcohol, acetone, ethyl acetate.
• Non-polar solvents: mineral oil, petrolatum, flower oils, seed oils, hexane, toluene, dimethyl ether.

Physical Absorption

• UV Filters:
  • PABA Derivatives (e.g. octyl dimethyl PABA).
  • Cinnamates (e.g. octyl methoxycinnamate).
  • Salicylates (e.g. weak UVB absorber).
  • Benzophenones (e.g. poor stability, used less frequently).
  • Avobenzone (e.g. UVA absorber, not photostable).
  • Titanium dioxide (e.g. broad spectrum, non-irritant, amphiphilic).
  • Zinc oxide (e.g. 200 nm particle size appears transparent, less whitening).

Vitamins

• Vitamin E: non-enzymatic antioxidant, alpha-tocopherol acetate ester converted to tocopherol in the skin.
• Vitamin C: water-soluble non-enzymatic antioxidant, protects from UVB damage if combined with Vitamin E.
• Vitamin A: stimulates cell proliferation and cell renewal, increases collagen content of the dermis, and increases elasticity and barrier function of the skin.
• Biotin: good for nails and hair due to effect on keratinization.
• Vitamin D: UV barrier.
• Vitamin B6: for decreasing sebum protection.
• Beta-Carotene: partnered with Vitamin E and C to protect the skin against UV damage.