Dermatological gels

Burton et al. reported the assay of benzoic acid, ethyl benzoate, and benzoyl peroxide in dermatological gels and lotions [33]. These workers used a Waters p-Bondapak C g column and UV detection at 254-nm. A mixture of 50% aqueous acetonitrile was used as the mobile phase. 

Today the population is becoming increasingly exposed to ultrafine particles (< 20 nm, e.g., Aerosil, 2) in bodycare and household products. Ion microscopy studies revealed that such particles can, for example, penetrate the horny layer of the skin and can result in unexpected interactions. SIMS and Fourier transform laser microprobe mass spectrometry (FT LMMS) have been applied to study 2 stimulated interaction in thin layers of dermatological gels as a result of UV irradiation.175 For future studies of distribution of ultrafine particles LA-ICP-MS will be employed. 

Carbomer is also compatible with dimethyl sulfoxide. The veterinary product, Domoso (Syntex Veterinary Labs), is a topical gel consisting of carbomer 934 and 90% dimethyl sulfoxide. Carbomer 940 gels exhibit superior optical clarity compared with 934 gels, and can be used in ophthalmic preparations. However, only carbomer 934 is approved for internal use. The mucoadhesive properties of carbomer were studied with triamcinolone acetonide, with acyclovir and to improve protein uptake across the nasal mucosa. Pharmaceutical gel products containing carbomer in their formulations are listed in Table 6. All are dermatological gels except for Anbesol Gel (Whitehall) and Pilopine HS (Alcon). 

S.A. Bhasha, S.A. Khalid, S. Duraivel, D. Bhowmik, K.P. Sampath Kumar. Recent trends in usage of polymers in the formulation of dermatological gels. Indian J Res Pharm Biotechnol. 1 (2) 161-168, 2013. 

Leyden JJ, Grove G, Zerweck C (2004) A doubleblind, comparative facial tolerance study of a new 10% sodium sulfacetamide 5% sulfur aqueous gel (in a 10% urea vehicle) vs a 10% sodium sulfacetamide 5% sulfur topical suspension in rosacea acne subjects with sensitive skin. In Abstract of the 62nd Annual Meeting of the American Academy of Dermatology. Washington DC, February 6-11,2004. Abstract P66... 

Pierard-Franchimont, C. and Pierard, G.E. A double-blind placebo-controlled study of ketoconazole + desonide gel combination in the treatment of facial seborrheic dermatitis. Dermatology, 204, 344—347 (2002). 

The better understanding of the mechanisms of stability incomplex dermatological emulsions stabilized by surfactants and amphiphiles has enabled the development of a rapid microscopic method for evaluation of potential emulsifiers. The method is based on the observation that good emulsifier blends that stabilize emulsions by the formation of multilayers of stable gel phase also swell spontaneously in water at ambient temperature and this process can be observed microscopically. Mixtures that do not form gel phase or form metastable gels only after a heating and cooling cycle cannot be observed to swell spontaneously at ambient temperature. ... 

Aloepfel is the colourless, mucilaginous gel obtained from the parenchyma cells in the central region of the leaves of Aloe barbadensis Mill. It has a dermatological use—see DOS C. 

CRA has been detected in humans [34] and was the first RAR-RXR pan-agonist discovered [35-37] and may be classified as a retinoid/rexinoid. It is the only retinoic acid isomer not approved for the common dermatological diseases. However, it has recently been launched in the US as adjuvant topical treatment of AIDS-associated Kaposi s sarcoma [38-41]. This agent is the first RXR ligand to be approved for the treatment of a dermatological disease. In a randomized study with 268 AIDS-associated Kaposi s sarcoma patients, 35% treated with alitretinoin (0.1% gel) had a positive response, compared with 18% treated with vehicle gel irrespective of the number of concurrent antiretroviral therapies [41], 9-CRA is in clinical trials for the treatment of various cancers, including breast cancer [42], renal cell carcinoma [43,44] and squamous cell carcinoma [45—47]. 

Tazarotene gel, a new retinoid, for topical therapy of psoriasis vehicle-controlled study of safety, efficacy, and duration of therapeutic effect. Journal of the American Academy of Dermatology, Z7, 85-92. 

In general, the preparation of such formulations as poultices and pastes is extemporaneous, and it is unlikely that the industrial pharmaceutical formulator will be required to develop stable, safe and efficacious products of this type. Solutions and powders lack staying power (retention time) on the skin and can only afford transient relief. In modern-day pharmaceutical practice, semi-solid formulations are preferred vehicles for dermatological therapy because they remain in situ and deliver their drug payload over extended periods. In the majority of cases, therefore, the developed formulation will be an ointment, emulsion or a gel. Typical constituents for these types of formulations are shown in Table 14.5. 

Absorption of substances from outside the skin to positions beneath the skin, including entrance into the blood stream, is referred to as percutaneous absorption. This is shovm in Figure 2.5. The absorption of a medicament present in a dermatological such as a liquid, gel, ointment, cream, paste, among others depends not only on the physical and chemical properties of the medicament but also on its behavior in the vehicle in which it is placed and upon the skin conditions. The vehicle influences the rate and degree of penetration, which varies with different drugs and vehicles. 

Nalidone . [UCIB] Sodium PCA moisturizer for dermatological so, shampoos, after-sun lotions, shower gels, moisturizing creams and lotions, hair c[Pg.244]

Tensvccin. [ICI PLC] Sulfosuccinate mild surfactant fcsr shanqxtos, bubble baths, shower gels, dermatological prqtarations. 

Zincidone . [UCIB] Zinc PCA cicatrizing and tissue hardening agent for dermatological sotq>, shampoo, shower gel, deodorants, nutritive creams. 

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