Other References:
British Journal of Dermatology, Vol. 77, Dec. 1965, pp. 622-626. .
J. of Invest. Derm., Vol. 32, Jan.-June 1959, pp. 599-604. .
Chemical Abstracts, Vol. 65:10423b, Referring to Belg. Patent 670,243 and Vol. 63:1106g to egg yolk..
Description:
BACKGROUND OF THE INVENTION
Prolonged exposure to the sun, particularly in light-skinned persons, generally leads to an initial redness of the skin which becomes brown after a period of time. This redness is generally painful and can result in the skin peeling. The damage to the skin is caused by the ultraviolet portion of sunlight in the range of about290-310 nm. Many attempts have been made to filter off the damaging ultraviolet wave lengths from the skin with externally applied sun screen agents. These sun screen agents are generally satisfactory while they are on the skin. They are disadvantageous since they do not remain on the skin for a sufficiently long time to be adequately effective and as a consequence have to be repeatedly reapplied at frequent intervals. Furthermore, many of the external sun screen agents are rather greasy and uncomfortable to the user.
There is thus a need for an effective sun screen agent which is efficacious upon prolonged use and which is facily administered.
DETAILED DESCRIPTION OF THE INVENTION
It has been found according to this invention that a sun screen agent as hereinafter defined can be administered internally and can be stored in sufficient amounts in the skin to bring about an effect similar to the filtering effect of conventional externally applied sun screen agents. According to this invention, it has been found that the internal administration of canthaxanthin in combination with other carotenoids has the desired effect. It has been found that when canthaxanthin is administered orally in combination with other carotenoids, it, as well as the other carotenoids, will become stored in the skin and prophylactically protect against sun erythema and sunburn and reduce photosenitivity.
While the use of canthaxanthin alone protects against sunburn, sun erythema and reduces photosensitivity, it imparts an undesirable reddish color to the skin, it can, however, be used successfully in combination with other carotenoids which are capable of being stored in the skin and which filter ultraviolet light rays in the 290-310 nm. range. Among those carotenoids which are suitable for use in oral sun screen compositions in combination with canthaxanthin are β-carotene, β-apo-8'-carotenal, β-apo-8'-carotenoic acid ethyl ester, bixin, zeaxanthin, crocetin, echinenone, citranaxanthin, torularhodin aldehyde, apo-4'-β-carotenal, C 30 -dialdehyde, lycopene, capsanthin, rhodoxanthin and astaxanthin.
The most preferred compounds of the above group for combination with canthaxanthin in sun screen compositions according to this invention, are β-carotene, β-apo-8'-carotenal and β-apo-8'-carotenoic acid ethyl ester. Of the remaining carotenoids which are suitable, bixin, zeaxanthin and crocetin are preferred.
The compositions containing the active ingredients are administered internally in any convenient dosage form, preferably in the form of capsules. The oral administration forms which are suitable, e.g., capsules, can contain various amounts of active ingredients, however, a total amount of from about 5 mg. to about 50 mg. of active ingredients, are generally used.
Preferably, however, the oral unit dosage form contains from about 10 mg. to about 30 mg. of active ingredients. The active ingredients are generally administered orally on a daily basis. The daily dosage amounts are usually from about 5 mg. to about 100 mg. of active ingredients administered in one or more doses throughout the day. It is preferable to administer about 50 mg. to about 100 mg. and particularly about 75 mg. of active ingredients daily. The dosages and dosage regimen described relate to adults. The dosage for children is generally about one-half the dosage for adults administered in a similar daily regimen.
In order to insure the prophylactic effect against sun erythema, sunburn and reduction of photosensitivity is effected and in order to insure that sufficient active ingredients have been stored in the tissues of the skin, it is necessary to treat the patient in the manner described continuously during the period of about 10 to 20 days before expected exposure to the sun. Tests on light skinned persons conducted according to the method of Wucherpfennig [Strahlentherapie Vol. 40, page 201 (1931)] have shown that the prophylactic use of the sun screen compositions of this invention produce a significant protective effect against ultraviolet rays and particularly protect against and delay the formation of erythema caused by the ultraviolet rays. Finally, prophylactic administration of the compositions of this invention to persons who are in general strong risks for sunburn, such as those exposed to strong sunlight in high elevations or on lakes, indicates the treatment is successful since such persons exhibited no sun erythema or sunburn.
When the combination preparations of canthaxanthin and one or more of the carotenoids listed are used, then the active combination should preferably contain at least about 50% by weight of canthaxanthin with the upper limit restricted only by the reddish color imparted to the skin. Preferably up to about 75 % canthaxanthin is used in the combination. The remainder of the active combination in the oral dosage form, e.g., from about 25 % to 50 % by weight is a carotenoid or mixtures thereof as listed above. The oral compositions can be made by conventional compounding procedures known in the pharmaceutical art, that is, by mixing the active substances with edible pharmaceutically acceptable non-toxic inert, solid or liquid carriers and/or excipients suitable for systemic administration and conventionally used in oral dosage forms. Additionally, edible, non-toxic pharmaceutically acceptable stabilizers such as the tocopherol compounds usually used as stabilizers in oral dosage forms or edible, non-toxic pharmaceutically acceptable salts thereof as well as ascorbic acid can be included in the compositions. All the above carriers, excipients and stabilizers are intended to include only those suitable for oral administration and all are conventional and known to the pharmaceutical compounding art.
In the following examples which illustrate the invention the expression "10%; water-soluble" signifies water-soluble preparations which contain 10% by weight of the corresponding carotenoid.
EXAMPLE 1
Capsules of the following composition are manufactured in a conventional manner:
Canthaxanthin (10%; water-soluble) 100 mg. carotene (10%; water-soluble) 100 mg. Mannitol 60 mg. Talcum 8 mg.
In the composition prepared according to this example equal weights of either β-apo-8'-carotenal, β-apo-8'-carotenoic acid ethyl ester or citranaxanthin can be used in place of β-carotene.
EXAMPLE 2
Capsules of the following composition are manufactured in a conventional manner:
Canthaxanthin (10%; water-soluble) 100 mg. carotene (10%; water-soluble) 100 mg. DL-α-Tocopheryl acetate 20 mg. Ascorbic acid 40 mg. Mannitol 90 mg. Talcum 12 mg.
In the compositions prepared according to this example, equal weights of either β-apo-8'-carotenal, β-apo-8'-carotenoic acid ethyl ester or citranaxanthin can be used in the place of β-carotene.