Treating hair by targeting enzymes

Details Treating hair by targeting enzymes Treating hair by targeting enzymes

2001-06-11

2002-06-04

Tate, Christopher R. (Department: 1651)

Drug, bio-affecting and body treating compositions

Live hair or scalp treating compositions

Permanent waving or straightening

C514S185000, C514S430000

Reexamination Certificate

active

06399052

ABSTRACT:

FIELD OF THE INVENTION
This invention relates to the treatment of hair with activators, inhibitors, co-factors or catalytic substrates for active endogenous hair fibre enzymes.
BACKGROUND AND PRIOR ART
The vast number of biochemical reactions that occur in every human cell are nearly all mediated by enzymes. Enzymes are biological catalysts, facilitating reactions under mild and physiological conditions. All enzymes have a defined function and are highly specific for the reactions they catalyse. A particular enzyme could therefore be targeted by a specific reagent, whilst other enzymes remain unaffected. In addition, the types of reactions catalysed by different enzymes is extremely variable, and each enzyme is capable of catalysing up to a million reaction events per second.
Enzymes are of particular interest for the development of new modes of benefit delivery in hair care. For example, U.S. Pat. No. 5,490,980 describes a composition for topical application to skin, hair or nails containing a beneficial active agent which has been functionalised with an alkylamine moiety, together with the enzyme transglutaminase (a calcium and thiol dependent enzyme responsible for the crosslinking of proteins by the formation of covalent bonds between lysine and glutamine residues). The transglutaminase in the composition is said to act as a catalyst to crosslink the active ingredient with glutamine residues in skin, hair or nails. The transglutaminase in the composition of U.S. Pat. No. 5,490,980 is sourced from guinea pig liver, slime mould, alfalfa or preferably bacterial fermentation.
Problems with the above approach include size exclusion of the exogenous enzyme, the expense of obtaining the exogenous enzyme, the possibility of immunological sensitisation from enzyme-containing formulations, and instability of the enzyme when stored in the formulation, particularly where high surfactant levels are present as in cleansing compositions. Furthermore, Gardner et al. (1995) J. Soc. Cosmet. Chem., 46, 11-28 provides evidence that glutamine residues on the surface of human hair are not, contrary to previous thought, recognised as a substrate for guinea pig liver transglutaminase. The authors of that paper found no conclusive evidence that virgin hair was modified by exogenously applied transglutaminase, and considered that the outer fatty acid layer of the hair probably restricted access to candidate glutamine sites, despite the large abundance of glutamine residues in hair, through hydrophobic repulsion or steric interactions. It was suggested that future work should be directed to cross-linking soluble protein or modified protein films co-deposited on hair together with the exogenous enzyme, so that the hair was not required to donate endogenous residues to the reaction.
Tsushima et al., Arch. Dermatol. Res. 284: 380-385 (1992) describes the purification and characterisation of a cystatin-type cysteine proteinase inhibitor (CPI) in the human hair shaft. In that paper, it is speculated that there are cysteine proteinases in hair, since there is CPI. However, the presence of any such enzymes within the hair fibre has, to date, not been reported in the literature.
The inventors have now found that the mature human hair fibre contains endogenous enzymes, which furthermore have been shown to be active and therefore capable of interaction with exogenously supplied substrates. The precise origin of these active endogenous hair fibre enzymes remains unclear. It is particularly surprising that these endogenous hair fibre enzymes have not only been shown by the inventors to be present, but also to be biologically active. Maturation of hair fibre results in the death of its constituent cells (Tamada et al. (1994) Br. J. Dermatol. 131: 521-524) and this coupled with the increased levels of intracellular cross-linking results in a mature fibre which is metabolically dead. Unexpectedly, the inventors have found that enzyme activity is in fact preserved, rather than denatured, during the processes of cellular keratinisation and death that occur during fibre growth.
SUMMARY OF THE INVENTION
The present invention provides the use of a hair benefit agent as an ingredient in a topical hair treatment composition for the purpose of targeting an active endogenous hair fibre enzyme when the composition is applied to the hair, thereby delivering a hair benefit via the interaction of the hair benefit agent with the enzyme.
Advantageously, the above approach solves the problems associated with the systems described previously involving application of exogenous enzyme. For example, enzyme substrates can be selected which are cheaper, safer and stabler to formulate into hair treatment compositions than exogenous enzyme, and which, unlike exogenous enzyme, are able to penetrate the hair and actually deliver enzyme-linked benefits to the underlying fibre matrix.
DETAILED DESCRIPTION AND PREFERRED EMBODIMENTS
Examples of active endogenous enzymes identified by the inventors to date within the mature human hair fibre fall in various and diverse classes and include:
Transglutaminase
Protease
Lipase
Steroid sulphatase
Catalase
Esterase
Hair Benefit Agents
Ingredients suitable for use as hair benefit agents according to the invention for targeting endogenous hair fibre enzymes may be any material which is capable of specifically interacting with the selected enzyme, or is chemically modified in order to do so. The material may serve as an enzyme activator, enzyme inhibitor, enzyme co-factor or catalytic substrate for the enzyme, in order to derive benefit.
Examples of the type of such ingredients include hair conditioning agents, (such as humectants, softeners and cuticle lubricants), hair colouring agents, antimicrobial compounds, UV-absorbing compounds, fluorescers, hair strengthening agents (such as fibre repair agents or fibre rebuilding agents), antioxidants, perfumes, and mixtures thereof.
Preferred ingredients for use according to the invention are selected to target the endogenous hair fibre enzymes which are classified below:
(i) Transglutaminase
Transglutaminase has been found to be active in the hair fibre, localised predominantly in the cuticle. It is a calcium and thiol dependent enzyme which is responsible for the crosslinking of proteins by the formation of covalent bonds between lysine and glutamine residues.
Ingredients suitable for use as hair benefit agents according to the invention for targeting endogenous hair fibre transglutaminase include catalytic substrates for this class of enzyme.
Catalytic substrates for transglutaminase are required to include (or be modified to include) at least one —R′NH
2
group in which R′ is a hydrocarbon or functionalised hydrocarbon chain. Preferably R′ is a straight aliphatic hydrocarbon chain containing from 1 to 8 carbon atoms.
Transglutaminase crosslinks the substrate through the alkyl amine (R′NH
2
) group to the glutamine residues in hair.
Accordingly, hair benefit agents suitable for use according to the invention as catalytic substrates for endogenous hair transglutaminase may be any compound which has a beneficial effect when delivered to human hair, as long as the compound contains, or is modified to contain, an alkyl amine group.
Use of such hair benefit agents as catalytic substrates for endogenous hair fibre transglutaminase enables a direct, in situ interaction between substrate and enzyme for delivering a localised and sustained hair fibre benefit derived from that interaction. In this way, permanent or internal hair benefits may be obtained from the transglutaminase-catalysed crosslinking reaction between a benefit agent and the substance of the hair fibre itself. Preferred benefit agents in this context are hair conditioning agents and hair colouring agents. Advantageously, such enzyme-catalysed interactions occur under physiological and naturally mild reaction conditions, so harsh chemical treatments are not necessary.
Preferably, in order to optimise the crosslinking reaction between transglutaminase and substrate, the R′

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