Cosmeceuticals Part 5

Peptides

Microcollagen
pentapeptides

Fibroblasts in aged tissue produce less collagen than those in younger skin, but their capability to produce collagen is still present. Fibroblast collagen production has been reported to be stimulated by a pentapeptide fragment of the collagen molecule.

At the carboxyl-terminal end of the collagen molecule is a fragment that has been identified as a participant in the regulation of its own synthesis. Lys-Thr-Thr-Lys-Ser pentapeptide is a potent stimulator of collagen and fibronectin synthesis, which are­ both important components of the interstitial matrix.

Copper peptides

The copper-dependent lysyl oxidase (LO) plays a critical role in the biogenesis of connective tissue matrices by crosslinking the extracellular matrix proteins, collagen and elastin. Levels of LO increase in many fibrotic diseases, while expression of the enzyme is decreased in certain diseases involving impaired copper metabolism.

Within the past decade, the gene encoding LO has been cloned, facilitating investigations of the regulation of expression of the enzyme in response to diverse stimuli and in numerous disease states. Transforming growth factor-beta, platelet-derived growth factor, angiotensin II, retinoic acid, fibroblast growth factor, altered serum conditions, and shear stress are among the effectors or conditions that regulate LO expression. Since the production of both collagen and elastin is reduced in aging skin and in skin exposed to ultraviolet light, copper peptides may be able to help produce new collagen and hence repair aged skin.

Antimicrobial agents

The use of antimicrobial agents in cosmetics and related toiletries has been rampant in recent years. It is increasingly found in baby oils, creams, and lotions to help prevent and control impetigo and milia; in deodorants, to inhibit microbial decomposition of perspiration; and in various scalp preparations, to inhibit microorganisms that are associated with seborrheic dermatitis.

Triclosan

This is the latest rage in the arsenal of antibacterial chemicals, included in detergents, dish washing fluids, soaps, deodorants, cosmetics, lotions, creams, and even toothpaste. Triclosan (2, 4, 4'-trichloro-2'-hydroxydiphenyl ether) is a broad-spectrum antimicrobial agent, routinely used in various personal care products. It is also incorporated into polymers through melt-mixing, with the aim of providing persistent antibacterial action on the surface of the polymer.

Chlorhexidine

Chlorhexidine is effective against a wide range of gram-negative and gram-positive vegetative bacteria, yeasts, dermatophyte fungi, and lipophilic viruses. It is inactive against bacterial spores except at elevated temperatures.

Povidone iodine

This compound is soluble in water, forming a golden brown solution. Like iodine, the solution of the iodine complex is bactericidal and fungicidal. However, unlike solutions of iodine, it is does not stain. The antiseptic action of
povidone-iodine solutions is due to the available iodine present in the complex.

PCMX (para-chloro-meta-xylenol)

PCMX is effective against both gram-positive and gram-negative bacteria and fungal and yeast microorganisms. PCMX has been tested as safe for use in long-term wound care and is more effective on a broader range of microorganisms than the other antiseptics.

Hydrogen peroxide

In solution, hydrogen peroxide provides mechanical cleansing and some debridement of wounds by its effervescent action; however, it can cause ulceration of newly formed tissue and can create granulomas. It is toxic to fibroblasts
and, therefore, should never be used as an aftercare solution for wounds.

Antidandruff preparations

Most preparations for the treatment of dandruff largely depend on antimicrobial agents for their therapeutic effect. One leading antidandruff lotion is a combination of benzethonium chloride and N-trichloroethyl mercapto-4-cyclohexene-1,2-dicarboximide. Biphenamine hydrochloride provides an excellent bacteriostatic antifungal property and local anesthetic action.

Zinc pyrithione

Zinc-2-pyridine-thiol-1-oxide is one of the most widely used antimicrobial agents, while lauryl
isoquinolinium bromide and bislauryltrimethylammonium polythionate are 2 other popular agents. In addition to their antiseborrheic properties, 2,2'-thiobis-4-chlorophenol and diiodohydroxyquin also exhibit antiseptic qualities.

Deodorants

Antimicrobial substances, such as hexachlorophene, aluminum phenolsulfonate, and zinc peroxide, as well as various quaternaries, such as cetyltrimethylammonium bromide, alkyldimethylbenzylammonium chloride, and iisobutylphenoxyethyldimethylbenzylammonium chloride, have been used in antiperspirant and deodorant formulations.

Tyrothricin and neomycin have also been used in deodorant formulations. Studies have shown that neomycin alone or in combination with aluminum chlorhydroxide produces effective odor suppression, along with a significant increase in gram-negative organisms. Its effectiveness as a deodorant is essentially attributed to its exceptional suppression of gram-positive organisms.

Trichlorocarbanilide is a high-duty, wide-spectrum bacteriostatic agent also used in deodorants. It has lasting safe and stable bactericidal effect. It also has high effects on inhibiting and killing gram-positive, gram-negative bacteria, fungus, saccharomycetes, and virus.

Other antimicrobial preparations

Several diverse chemical substances are used in the therapy for various fungal infections, including fatty acids and their derivatives (eg, zinc, calcium, alkanolamine undecylenates), phenolics (4-halothymols), halogenated quinolines (iodochlorhydroxyquin), quaternary ammonium salts (hexadecamethylenebis-isoquinolinium chloride), and sulfur and
sulfur compounds (zinc ethylene bisdithiocarbamate). Phenol and polyphenol derivatives that are used in cosmetic formulations include hexylresorcinol, p-chloro-m-xylenol, o-phenylphenol, and chlorothymol. Quaternary ammonium compounds that are used in cosmetic formulations include benzalkonium chloride, benzethonium chloride, cetylpyridinium chloride, and cetyltrimethylammonium bromide.

Topical anesthetics and antipruritics

Specific local anesthetic agents are often found in a variety of topical drugs and toiletry products, such as hand and scalp lotions, foot preparations, and aftershave products, to relieve local discomfort and to reduce pruritus. The anesthetic agents are also found in formulations designed to be useful in diaper dermatitis, sunburn, and acne vulgaris.

Ethyl aminobenzoate

Ethyl aminobenzoate (benzocaine) perhaps has been one of the most widely used local anesthetics; however, the increasing incidence of sensitization has prompted the introduction of noncaine anesthetics.

Benzyl alcohol

In creams, lotions, and ointments, benzyl alcohol at a 2% level provides effective local anesthetic effects and preservative qualities.

Diperodon hydrochloride

Diperodon hydrochloride and monohydrate are piperidine compounds in the class of N-substituted aminobenzenes. At approximately a 1% level, they provide local anesthetic effects and antipruritic actions.

Pramoxine hydrochloride

Pramoxine hydrochloride, which is reportedly more potent than cocaine, is used in topical preparations at concentrations of about 1%; however, the monohydrate salt is often preferred in some applications because it is not alkali sensitive, it is more soluble with various solvents, and it may avoid certain color changes or darkening in products that contain
hydrochloride-sensitive components. Specific local anesthetic agents, such as benzocaine, pramoxine, and diperodon, exert their effects on mucous membranes and abraded, broken, or irritated cutaneous membranes. They are not effective on unbroken skin.

Menthol

Menthol and related cooling compounds are widely used in products that range from common cold medications to toothpastes, confectionery, cosmetics. Menthol affects the nerve endings to provide a cooling antipruritic action.

Capsaicin

Topical application of capsaicin is thought to deplete substance P from local sensory nerve terminals. In experiments on human skin, inflammation was induced by injection of substance P (SP) or histamine intradermally, UV
irradiation, nonimmunologic contact urticaria, tuberculin reaction, contact allergens, and benzalkonium chloride with or without capsaicin pretreatment. The flare response to SP and histamine was suppressed by capsaicin pretreatment, whereas the wheal was enlarged. Interestingly, capsaicin pretreatment enhanced the responses to all other inflammatory agents.