Bases, dermatological

Williams, H. et al., Evidence-Based Dermatology. BMJ Publishing Group, London, 2003. 

Williams, H., Dowling Oration 2001. Evidence-based dermatology—a bridge too far , Clin. Exp. Dermatol., 26, 714, 2001. 

Barfod, T.S., Placebo in evidence-based dermatology, in Evidence-based dermatology, McKibbon, A. BC Decker Inc, Hamilton, 2002, pp. 97-112. 

Although the field is served by general dermatologists, occupational physicians, and occupational dermatologists, other health workers are also frequently involved. For this reason, we have deliberately included a number of redundancies in an attempt to make it easier for the reader. Whenever possible, we have emphasized evidence-based dermatology, and the authors were chosen on the basis of both their scientific approach and clinical good sense. 

The anhydrous petrolatum base may be made more miscible with water through the use of an anhydrous liquid lanolin derivative. Drugs can be incorporated into such a base in aqueous solution if desired. Poly-oxyl 40 stearate and polyethylene glycol 300 are used in an anti-infective ointment to solubilize the active principle in the base so that the ointment can be sterilized by aseptic filtration. The cosmetic-type bases, such as the oil-in-water (o/w) emulsion bases popular in dermatology, should not be used in the eye, nor should liquid emulsions, owing to the ocular irritation produced by the soaps and surfactants used to form the emulsion. 

Caldero, G., Pi Subirana, R., Llosas Bigorra, J. and Torres Fernandez, M. (2001) Use of alkyl(ether) phosphates (I). European Patent EP 1264633. Sonneville-Aubrun, O. and Simonnet, J.-Th. (2001) Nanoemulsion based on anionic polymers, and uses thereof especially in the cosmetic, dermatological, pharmaceutical and/or ophthalmic fields. European Patent EP 1160005. 

Based on a combination of available human case studies and experiments with laboratory animals, the major public health concerns associated with exposure to 1,4-dichlorobenzene are effects on the liver, kidneys, and blood. Some immunological, dermatological, and neurological effects have also been reported in exposed humans. There is information from animal studies which raises the question of whether 1,4-dichlorobenzene can cross the placenta and elicit structural effects on the developing fetus. Data from a study conducted in rats using the intraperitoneal route have demonstrated sperm abnormalities. Cancer of the liver as a result of lifetime exposure to 1,4-dichlorobenzene has been shown in mice, and renal cancer has been reported in male rats. However, recent studies related to the mechanism of renal carcinogenesis in rats suggest that these tumors may not be expected to occur in exposed humans. Issues relevant to children are explicitly discussed in Section 2.6, Children s Susceptibility, and Section 5.6, Exposures of Children. 

All dermatologic agents having a lipophilic base adhere to the skin as a water-repellent coating. They do not wash off and they also prevent (occlude) outward passage of water from the skia The skin is protected from drying, and its hydration and elasticity increase. 

In the light of these observations and the newer trends in product formulation, it was decided to study the in vitro release and permeation of propranolol hydrochloride from various hydrophilic polymeric matrices using the cellulose membrane and the hairless mouse skin as the diffusion barriers and to evaluate the effects of some of the additive ingredients known to enhance drug release from dermatological bases. 

The remarkable efficacy of topical corticosteroids in the treatment of inflammatory dermatoses was noted soon after the introduction of hydrocortisone in 1952. Numerous analogs are now available that offer extensive choices of potencies, concentrations, and vehicles. The therapeutic effectiveness of topical corticosteroids is based primarily on their antiinflammatory activity. Definitive explanations of the effects of corticosteroids on endogenous mediators of inflammation await further experimental clarification. The antimitotic effects of corticosteroids on human epidermis may account for an additional mechanism of action in psoriasis and other dermatologic diseases associated with increased cell turnover. The general pharmacology of these endocrine agents is discussed in Chapter 39. 

Urea in a compatible cream vehicle or ointment base has a softening and moisturizing effect on the stratum corneum. It has the ability to make creams and lotions feel less greasy, and this has been utilized in dermatologic preparations to decrease the oily feel of a preparation that otherwise might feel unpleasant. It is a white crystalline powder with a slight ammonia odor when moist. 

Since 1969, bovine pancreatic DNase 1 has been used for the treatment qf ulcers in dermatology [82-84]. It degrades the polynucleotides that are a main constituent of dwid ullr. One dermatolosical moduet based on DNase f is EImc . 

Early on, x-rays were used for structure determination, and Bragg, father and son, are justly regarded as portal figures in this basic research application of the mysterious rays. The development of this and other analytical methods based on x-ray techniques has had a pronounced impact on modern biology. This chapter will briefly outline the history of x-ray absorption in biological research and then concentrate on the application of micro probes with special reference to the proton probe in experimental dermatology. References to results from other techniques will, however, be included. 

Petrolatum continues to be used quite extensively in dermatological applications, primarily for three purposes (1) as an inert patch testing base, (2) as a vehicle in the dermal application of pharmaceuticals, and (3) as a treatment product itself. 

There are some well-described deficiency syndromes, the well-established therapeutic use of vitamin K antagonists as oral anticoagulants and the well-known positive effects of pantothenic acid on skin hydration/moisturization and wound healing, which apparently lacks scientific solid base. Apart from that there are not many studies available on the treatment of dermatological disorders with these vitamins, either systemically or topically. Even less is known about transdermal penetration, stability, and formulation dependencies of possible topical applications. 

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