Skin definition

Morizot, F., Le Fur, I., and Tschachler, E., Sensitive skin, definitions, prevalence and possible causes, Cosmet. Toiletries, 113, 59, 1998. 

To understand perfume behaviour on these surfaces and/or matrices, we must consider the range of attractive or repulsive forces between the perfume components and the surface itself. The situation is complicated by the way in which perfume is delivered to the surface. For example, for a perfume ingredient in a soap bar to be substantive it must first be efficiently delivered to the skin during washing, it must then survive rinsing and, finally, it must be retained for some time on the skin. Definitions of substantivity and of retention vary, but here retention is used to indicate the affinity a perfume has for a substrate when delivered to it, whilst substantivity also includes delivery barriers. 

Toxicology. The acute oral and dermal toxicity of naphthalene is low with LD q values for rats from 1780—2500 mg/kg orally (41) and greater than 2000 mg/kg dermally. The inhalation of naphthalene vapors may cause headache, nausea, confusion, and profuse perspiration, and if exposure is severe, vomiting, optic neuritis, and hematuria may occur (28). Chronic exposure studies conducted by the NTP ia mice for two years showed that naphthalene caused irritation to the nasal passages, but no other overt toxicity was noted. Rabbits that received 1—2 g/d of naphthalene either orally or hypodermically developed changes ia the lens of the eye after a few days, foUowed by definite opacity of the lens after several days (41). Rare cases of such corneal epithelium damage ia humans have been reported (28). Naphthalene can be irritating to the skin, and hypersensitivity does occur. 

This definition estabUshes the legal difference between a dmg and a cosmetic. It is clearly the purpose of, or the claims for, the product, not necessarily its performance, that legally classifies it as a dmg or a cosmetic in the United States. For example, a skin-care product intended to beautify by removing wrinkles may be viewed as a cosmetic because it alters the appearance and a dmg because it affects a body stmcture. 

Tbe term structural foam was originally coined by Union Carbide to describe an injection moulded thermoplastic cellular material with a core of relatively low density and a high-density skin. The term has also been used to describe rigid foams that are load bearing. Today it is commonly taken to imply both of the above requirements, i.e. it should be load bearing and with a core of lower density than the skin. In this section the broader load-bearing definition will be used. Whilst structural foams are frequently made from polymers other than polystyrene, this polymer is strongly associated with such products and it is convenient to deal with the topic here. 

Is it likely to eause skin eontamination or be absorbed through the skin (NB some materials have a definite Sk notation in EH 40.)... 

Class and Definition Cutaneous hazards- affect the dermal layer (skin) of the body... 

TABLE 21 Skin Irritation Scores and Verbal Definitions... 

In conclusion, until now insufficent data have been available to define general rules to predict for which drugs liposome encapsulation will be therapeutically beneficial when applied to the skin. It is too early to draw definite conclusions about the advantage of the vise of liposomes over alternative dermal delivery systems in the therapy for drugs designed to exert a pharmacological effect either locally or systemically. 

A vitamin is defined as an organic compound that is required in the diet in small amounts for the maintenance of normal metabofic integrity. Deficiency causes a specific disease, which is cured or prevented only by restoring the vitamin to the diet (Table 45-1). However, vitamin D, which can be made in the skin after exposure to sunhght, and niacin, which can be formed from the essential amino acid tryptophan, do not stricdy conform to this definition. 

The AUC is a measure of bioavailability, i.e. the amount of substance in the central compartment that is available to the organism. It takes a maximal value under intravenous administration, and is usually less after oral administration or parenteral injection (such as under the skin or in muscle). In the latter cases, losses occur in the gut and at the injection sites. The definition also shows that for a constant dose D, the area under the curve varies inversely with the rate of elimination kp and with the volume of distribution V. Figure 39.6 illustrates schematically the different cases that can be obtained by varying the volume of distribution Vp and the rate of elimination k both on linear and semilogarithmic diagrams. These diagrams show that the slope (time course) of the curves are governed by the rate of elimination and that elevation (amplitude) of the curve is determined by the volume of distribution. 

The cause of pruritus is unknown, although several mechanisms have been proposed. Vitamin A is known to accumulate in the skin and serum of patients with CKD, but a definite correlation with pruritus has not been established. Histamine may also play a role in the development of pruritus, which may be linked to mast cell proliferation in patients receiving hemodialysis. Hyperparathyroidism has also been suggested as a contributor to pruritus, despite the fact that serum PTH levels do not correlate with itching. Accumulation of divalent ions, specifically magnesium and aluminum, may also play a role in pruritus in patients with CKD. Other theories that have been proposed include inadequate dialysis, dry skin, peripheral neuropathy, and opiate accumulation.43... 

Early diagnosis of skin cancer is the key to improved prognosis. Diagnostic accuracy and clinical skills are two essential factors in the appropriate management of skin cancer. On presentation to a clinician s office, patients may offer a history of a new growth or an area of irritation. Conversely, the skin cancer may have been present for years undetected by the patient. The definitive diagnosis of any suspected cutaneous malignancy should be confirmed by a biopsy prior to treatment. 

FMC. 1991b. Durad 125. Non-definite primary skin irritation study in rabbits. FMC Corporation, Princeton, NJ. 

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