Drug – bio-affecting and body treating compositions – Inorganic active ingredient containing – Elemental sulfur or compound thereof
Reexamination Certificate
2001-06-11
2004-02-10
Pak, John (Department: 1616)
Drug, bio-affecting and body treating compositions
Inorganic active ingredient containing
Elemental sulfur or compound thereof
C424SDIG001, C514S875000, C514S880000, C514S881000, C514S919000, C514S937000, C514S944000
Reexamination Certificate
active
06689394
ABSTRACT:
INTRODUCTION TO THE INVENTION
The present invention relates generally to the removal of ectoparasites from the bodies of humans and animals, and more particularly to a topical treatment to facilitate such removal.
Ectoparasitic infestation of humans and animals is a serious health problem throughout the world. Of particular importance as a public health issue is pediculosis, or infestations with lice, which are pervasive among children and can quickly be spread in a school setting. A very common parasite is
Pediculus humanus
var
capitis
, the common head louse, although there are other important parasites, including
Pthirus pubis
(the pubic louse) and
Pediculus humanus
var
corporis
(the body louse). Infestations are frequently accompanied by itching and skin damage. Infections may occur when the skin is scratched in an attempt to relieve the itching. Further, lice are known to be capable of transmitting serious diseases, including trench fever, relapsing fever and typhus.
Pediculosis is most frequently treated by applying pesticidal compositions, such as lotions or shampoos, to the affected body areas, such as the hair, and then exhaustively combing with a fine-toothed comb made especially for the purpose of removing nits. Commercially available preparations may include as their active ingredients pyrethrins, piperonyl butoxide, malathion, lindane or permethrins, many of which unfortunately have neurotoxic properties, are readily absorbed through the skin and therefore can establish undesirable systemic concentrations. It is perceived that the effectiveness of pesticides has recently diminished, as the parasites appear to continually become more resistant to their action. The resistance may be aggravated by small amounts of residual pesticide on the treated areas, following the procedure. This resistance also contributes to an increased opportunity for toxic systemic exposure to the active ingredients, since the preparations must be applied repeatedly to obtain an eradication of the infestation. Further, the pesticides do not usually kill the parasite's eggs that may be present on a host, so the tedious mechanical removal techniques must also be used.
DiNapoli et al., “Eradication of Head Lice with a Single Treatment,”
American Journal of Public Health
, Vol. 78, pages 978-980, 1988, reported a study in which 7 percent of patients treated with a commercial 1 percent permethrin cream rinse, and 16 percent of patients treated with a commercial product containing 0.3 percent pyrethrins, 3 percent piperonyl butoxide, 1.2 percent petroleum distillate and 2.4 percent benzyl alcohol, experienced adverse reactions including pruritis, erythema, tingling, rash and other conditions. Further, by 14 days following treatment 38 percent of the patients treated with the pyrethrin product were found to host live lice, considered a treatment failure. Permethrin is described as having residual activity on the hair for up to two weeks.
R. J. Roberts et al., “Comparison of Wet Combing with Malathion for Treatment of Head Lice in the UK: a Pragmatic Randomised Controlled Trial,”
The Lancet
, Vol. 356, pages 540-544, 2000, report that mechanical removal of lice with a commercial comb every 3-4 days for two weeks gave a “cure” rate of only 38 percent, while two treatments with 0.5 percent malathion lotion seven days apart gave a “cure” rate of 78 percent.
Published results for the various topical pesticidal treatments were compared by. R. H. Vander Stichele et al., “Systematic Review of Clinical Efficacy of Topical Treatments for Head Lice,”
British Medical Journal
, Vol. 311, pages 604-608, 1995. It was concluded that only permethrin had sufficient evidence of efficacy.
There are other approaches to treating the infestations, including the application of heavy, oily substances such as mineral oil, petrolatum, mayonnaise and the like in an attempt to suffocate the ectoparasites, but these have not been found particularly effective, esthetically pleasing or convenient. One major disadvantage of such treatments is the prolonged time (usually several hours) required to achieve suffocation, after the agent has been applied.
The suffocation technique has been refined, such as by the approach of U.S. Pat. No. 6,139,859 to Precopio which utilizes air-impermeable water-dispersible liquid compositions containing surface active agents. Another type of treatment refinement is the technique of Pearlman et al. in PCT International Publication WO 99/18800, involving the topical application of surfactant substances as “pediculostatic agents” which immobilize the parasites to permit their removal by combing.
It remains desirable to have a treatment for ectoparasitic infestations which is efficacious, acts rapidly and does not generate great discomfort or require any exposure of the host to toxic agents.
SUMMARY OF THE INVENTION
The present invention is a treatment for ectoparasitic infestations, particularly those involving fleas, ticks, mites or lice, comprising establishing environmental conditions whereby systemic moisture is removed from the ectoparasites, for a time sufficient to cause immobilization or death of the ectoparasites, then removing the pests by mechanical means such as combing.
This invention involves topical applications of compositions containing active ingredients which have a strong affinity for water, such as is present in organisms such as ectoparasites. Contact of the organisms with the active agents causes desiccation which results in immobilization and/or mortality of the parasites, facilitating their mechanical removal by combing and other techniques. In many instances, the active agents also change the microenvironmental pH conditions; this can also have a significant adverse effect on mobility of the organisms and viability of their eggs.
Treatment of ectoparasites can be conducted using a composition which generates a strong hydration reaction, when contacted with water. In one embodiment, the composition is a particulate solid, a semi-solid or a fluid containing substantially no aqueous matter, or in some instances only a small amount of water, and which contains a particulate inorganic substance that undergoes a strong hydration reaction in the presence of water. Examples of suitable substances are salts of alkali metals and alkaline earth metals. The hydration reaction is not necessarily one which results in formation of any new chemical compound, but can be an absorption-type reaction, and may be exothermic, endothermic or not involve any significant temperature changes.
DETAILED DESCRIPTION OF THE INVENTION
The invention will be described primarily as it relates to the reduction of human head lice infestations, although those skilled in the art will recognize its applicability to other ectoparasites and animal subjects, and the inventors intend that their invention will have such applicability.
In the following description and the claims, it is intended that a reference to a percentage means percent by weight, unless the context clearly indicates otherwise. Since the chemical names for certain composition ingredients are quite cumbersome, some ingredients are identified herein by their adopted names as given in standard reference works, including J. A. Wenninger et al, Eds.,
International Cosmetic Ingredient Dictionary and Handbook,
8
th
Ed., The Cosmetic, Toiletry and Fragrance Association, Washington, D.C., 1999.
Lice egg cases (“nits”) are thought to be attached to hair by means of mucopolysaccharide adhesive substances. Removal of the nits therefore requires a very thorough combing operation, and is not appreciably facilitated by many of the usual pesticide treatments. However, embodiments of the present invention provide both desiccation and a changed pH in the microenvironment of the nit, which can alter the physical and chemical nature of the egg casing itself. The provision of lubricious agents in a composition also can facilitate lice and nit removal by combing.
Suitable active agents for use in the present invention are generally those salts of alkal
Anthony Frank A.
Schlesinger Marcia S.
Van Scoik Kurt G.
Franks Robert A.
Pak John
Schering-Plough HealthCare Products Inc.
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