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PARSOL SLX Sunscreen Compositions

IP.com Disclosure Number: IPCOM000006995D
Publication Date: 2002-Feb-15

Publishing Venue

The IP.com Prior Art Database

Related People

Liam Smith: AUTHOR

Abstract

The disclosure relates to the sunscreen Benzylidene Malonate Polysiloxane (PARSOL SLX), (also known as Polysiloxane A as disclosed in US patent No. 6,193,959) solvated in a series of organic solvents. The wavelength of maximum absorbance (lmax) of the sunscreen is shifted through the UV region to differing degrees dependant up on the solvent used. The combination of sunscreen and solvent is then used in topical cosmetic and toiletry formulations to offer sun protection.The combinations of Benzylidene Malonate Polysiloxane with solvent are used in a range of formulations, to achieve the absorbance of UV light in the preferred region, to protect active ingredients as colour, fragrance or vitamins from UV degradation. For example, if a vitamin was sensitive to UV radiation of wavelength 340nm, Almond oil would be used to solubilise the sunscreen prior to incorporation into the formulation. Another area of use is to achieve UV protection in for the skin in other wavelengths unobtainable with the current sunscreen system. It is also possible to select wavelengths to protect or expose specific biological substrates i.e. UV activated repair enzymes in the skin or Langerhans cells in the immune system by using Benzylidene Malonate Polysiloxane and the correct solvent. The solvation of Benzylidene Malonate Polysiloxane in the correct solvent will locate the absorption peak in the area desired.

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PARSOL SLX™ Research Disclosure

The disclosure relates to the sunscreen Benzylidene Malonate Polysiloxane (PARSOL SLX™), (also known as Polysiloxane A as disclosed in US patent No. 6,193,959) solvated in a series of organic solvents.  The wavelength of maximum absorbance (lmax) of the sunscreen is ‘shifted’ through the UV region to differing degrees dependant up on the solvent used.  The combination of sunscreen and solvent is then used in topical cosmetic and toiletry formulations to offer sun protection.

The sunscreen has a polysiloxane backbone with UV absorbing Chromophores branched from it.  The lambda max (lmax) of the sunscreen is recorded at 313nm in ethanol.

The first part of the disclosure relates to the observed ‘shifting’ of this peak in different organic solvent media.  This ‘shifting’ shows the peak moving throughout the UVB-UVA region (290-400nm). The range observed is from 308.8nm-370nm.

Method

1% solutions of the sunscreen Benzylidene Malonate Polysiloxane were prepared in the solvents below and the absorbance profiles measured using a UV spectrophotometer.  The wavelength of the maximum absorbance was then recorded.

Table 1.

Organic Solvent

Absorbance Wavelength of Parsol SLX

Ethanol

313nm

C12-15 Alcohols Benzoate (Crodamol AB)

333nm

Dioctyl Maleate

327.5nm

Ceitol 868

315nm

Isopropyl Palmitate

310.9nm

Isopropyl Myristate

312nm

Silicone Fluid 345DC

308.8nm

Tridecyl Salicylate (Cosmacol ESI)

365nm

Butyloctyl Salicylate

355.4nm

Liquid Paraffin BP

310.7nm

Almond Oil BP

340nm

Deodorised Winter Sunflower Oil

333.4nm

Polydecene (Nexbase)

310.7nm

It is noted that there is a relationship between the (lmax) and the polarity of the solvents.

Ethanol and IPA are included for reference.

The combinations of Benzylidene Malonate Polysiloxane with solvent are used in a range of formulations, to achieve the absorbance of UV light in the preferred region, to protect active ingredients as colour, fragrance or vitamins from UV degradation.  For example, if a vitamin was sensitive to UV radiation of wavelength 340nm, Almond oil would be used to solubilise the sunscreen prior to incorporation into the formulation.  Another area of use is to achieve UV protection in for the skin in other wavelengths unobtainable with the current sunscreen system.  It is also possible to select wavelengths to protect or expose specific biological substrates i.e. UV activated repair enzymes in the skin or Langerhans cells in the immune system by using Benzylidene Malonate Polysiloxane and the correct solvent.  The solvation of Benzylidene Malonate Polysiloxane in the correct solvent will locate the absorption peak in the area desired.

This observation covers Benzylidene Malonate Polysiloxane in formulations present in the amount 0.1% to 10% by weight of the composition alone and in combination with a range of organic and inorganic sunscreening agents, i.e.

Suitable inorganic sunscreening agents include:

a)                     Microfine titanium dioxide;

b)                   Microfine zinc oxide; and

c)                   Iron oxid...