Sunscreen agents
AssigneeChesebrough-Pond's USA Co., Division of Conopco, Inc.
InventorsStuart W. Carr, Kevin R. Franklin, Charles C. Nunn, Jeffrey J. Pasternak, Ian R. Scott
Life of this patent
Estimating the term…
Abstract
A sunscreen composition for application to human skin comprises an ultraviolet absorber which is introduced as an anion into a layered double hydroxide of the general formula [N.sub.m N.sub.n (OH).sub.2(m+n) ].sup.y+ X.sup.x-.sub.y/x .multidot.zH.sub.2 O where M is a divalent metal or lithium, N is a trivalent metal and X denotes anions present as an interlayer between layers of metal atoms joined through the OH groups. Such layered double hydroxides are, for this invention, suspended in a cosmetically acceptable vehicle.
Claims18
A sunscreen composition for application to human skin comprising an effective amount of:
- (i) cosmetically acceptable vehicle;
- and incorporating
- (ii) from 0.05% to 50% by weight of the composition of a layered double hydroxide of the formula
- [M.sub.m N.sub.n (OH).sub.2(m+n) ].sup.y+ X.sup.x-.sub.y/x .multidot.zH.sub.2 O (I)
- wherein N is one or a mixture of trivalent metal ions selected from the group consisting of aluminum, chromium, iron, nickel, manganese, and scandium M is a divalent metal ion selected from the group consisting of magnesium, zinc, calcium, cobalt, nickel, copper, manganese and iron, or is lithium,
- if M is divalent y=n and if M is lithium y=(n-m),
- and X denotes interlayer anions, from 5 to 100 mole % of which display ultraviolet absorption with a molar extinction coefficient of at least 2.times.10.sup.3 over at least a portion of the wavelength range from 290 to 400 nanometers.
- wherein said layered double hydroxide is dispersed in said vehicle.
The composition of claim 8 wherein a majority of the interlayer anions X are selected from the group defined in claim 12.
A sunscreen method for application to human skin comprising an effective amount of:
- (i) a cosmetically acceptable vehicle;
- and
- (ii) from 0.05% to 50% by weight of the composition of a layered double hydroxide of the formula
- [M.sub.m N.sub.n (OH).sub.2(m+n) ].sup.y+ X.sup.x-.sub.y/x .multidot.zH.sub.2 O (I)
- wherein N is one or a mixture of trivalent metal ions selected from the group consisting of aluminum, chromium, iron, nickel, manganese, and scandium, M is a divalent metal ion selected from the group consisting of magnesium, zinc, calcium, cobalt, nickel, copper, manganese and iron, or is lithium,
- if M is divalent y=n and if M is lithium y=(n-m),
- and X denotes interlayer anions, from 5 to 100 mole % of which display ultraviolet absorption with a molar extinction coefficient of at least 2.times.10.sup.3 over at least a portion of the wavelength range from 290 to 400 nanometers,
- wherein said layered double hydroxide is dispersed in said vehicle.
Dependencies are inferred from the claim text.