Drug – bio-affecting and body treating compositions – Topical sun or radiation screening – or tanning preparations
Patent
1998-04-16
1999-04-20
Azpuru, Carlos A.
Drug, bio-affecting and body treating compositions
Topical sun or radiation screening, or tanning preparations
424 63, 424401, 424600, 424639, 424641, 424630, 514836, A61K 740, A61K 742
Patent
active
058956425
DESCRIPTION:
BRIEF SUMMARY
The present invention relates to a topical composition which is suitable for the treatment of tyrosinase-positive depigmentation disorders and, in particular, treatment of vitiligo. The composition is also suitable for the enhancement of suntanning, particularly the suntanning of fair skin (ie types I and II skins). The composition has improved catalase activity compared to previously known compositions. Methods are also provided for the improvement of the catalase activity of a pseudocatalase composition.
WO-A-92/20354 discloses that vitiligo and other tyrosinase-positive depigmentation disorders can be treated by exposing a patient to UVB light after topical application of a pseudocatalase. A preferred pseudocatalase is manganese (II) bicarbonate complex, prepared by adding manganous chloride to an aqueous solution of sodium bicarbonate, and then mixing the resulting liquid with a hydrophilic cream (100 g of Neribas).
WO-A-92/20321 discloses that suntanning can be enhanced by topical application of a pseudocatalase. The same pseudocatalases are exemplified as in WO-A-92/20354.
Both of these treatments rely upon the in vivo catalytic dismutation of hydrogen peroxide by the pseudocatalase.
It has now been discovered that the said catalytic activity of a pseudocatalase can be increased by the addition of a chelating agent. Particularly suitable chelating agents are EDTA or EDTA analogues and salts thereof.
WO-A-92/20354 and WO-A-92/20321 disclose a composition of manganous chloride (380mg), a solution of sodium bicarbonate (2.3 g) in purified water (3.0 ml), and Neribas (100 g). Neribas is a well-known cream vehicle which contains Macrogol stearate 2000; stearyl alcohol; liquid paraffin; white soft paraffin; polyacrylic acid; sodium hydroxide; disodium EDTA (i.e. ethylenediaminetetraacetic acid disodium salt); methyl and propyl paraben (i.e. 4-hydroxybenzoic acid methyl and propyl esters); and water. The EDTA is present in the cream base for the conventional purposes of removing trace elements which can catalyse autoxidation of oxygen sensitive excipients and boosting the antimicrobial activity of preservatives (eg parabens). There is no suggestion in either of the earlier applications that EDTA improves the catalytic activity of manganese (II) bicarbonate and there was no appreciation at that time that such an effect might exist.
Preferred pseudocatalases disclosed in the Applicant's earlier applications are transition metal bicarbonate complexes. It has now been discovered that the stability of a topical composition comprising a transition metal bicarbonate complex can be improved by storing the composition under carbon dioxide, preferably under pressure in aerosol form. Manganese (II) bicarbonate is thought to be in equilibrium with carbon dioxide, manganese (II) carbonate and water. The presence of carbon dioxide is thought to shift the equilibrium in favour of bicarbonate ions, thereby stabilising them.
According to a first aspect of the present invention, there is provided a topical composition comprising a complex of ions of a transition metal, bicarbonate ions and a chelating agent for chelating the transition metal, provided that, when the composition includes a cream vehicle comprising EDTA, the amount of EDTA is more than 0.1% w/w of the vehicle.
In a second aspect of the invention there is provided a topical composition in aerosol form, comprising a propellant and a complex of ions of a transition metal, bicarbonate ions and a chelating agent for chelating the transition metal.
In a preferred embodiment, the composition additionally comprises a lipid, for example petrolatum, stearyl alcohol, parol, liquid paraffin, white soft paraffin, coconut oil, almond oil, squalene, or any combination thereof.
It is thought that the complex may be partially soluble in the lipid phase, thereby causing the equilibrium between manganese (II) carbonate and manganese (II) bicarbonate to shift towards the latter. This may serve to increase the amount of complex which can be formed so that the activity of compositi
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Matkin David A.
Sanders Colin
Wareham Neale C.
Azpuru Carlos A.
Seidleck Brian K.
Stiefel Laboratories, Inc.
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