Drugs dithranol

It has been proposed that anthralin-associated toxicity might be suppressed by systematic antioxidant administration [295]. The treatment of psoriatic patients with another drug dithranol resulted in a decrease in in vivo oxygen radical generation [296]. 

A few drugs depend for their therapeutic action upon light activation. Included in this review are dithranol, which has been suggested to exert its antipsoriatic action in this way, and the psoralens, which have long been used in combination with sunbathing to treat various skin conditions and now are also used against surface cancers. 

In a second experiment (Hanhijarvi, Nevalainen, and Mannisto, 1985), the chronic, cumulative dermal effects of anthralin chemicals were studied in minipigs. Using only 12 animals, they were able, by having 32 sites per animal, to study the effects of two different chemicals (dithranol and butantrone both anthralins) in three different formulations at three different concentrations each. The protocol also included observations for systemic toxicity, clinical laboratory measurements, plasma drug analyses, and gross and histopathological examinations. 

Dantron (danthron 1,8-dihydroxyanthraquinone) (Figure 3.34) is known as a natural product, but for drug use is produced synthetically. It is prescribed to relieve constipation in geriatric and terminally ill patients. Dithranol (1,8-dihydroxyanthrone) is used as topical agent to treat troublesome cases of psoriasis. Diacetylrhein is marketed in some countries for the treatment of osteoarthritis. 

A second indication for keratolytical and some moisturizing agents (e.g., urea) is the penetration enhancement of topically applied antipsoriatic drugs (e.g., salicylic acid in the dithranol and coal tar treatment or corticosteroids). This may result in an economical benefit.11... 

Urea has been shown to be an efficient accelerant for the penetration of different drugs.52-57 Increased levels of hydrocortisone, triamcinolone acetonide,53 dithranol,54 and retinoic acid52 were found in various layers of isolated human skin after 1000 min of exposure time to creams containing 10 to 12% urea. Also the penetration of ketoprofen through isolated rat skin was enhanced by the addition of urea.56 Furthermore, it has been shown that the time of onset of erythema, induced by hexyl nicotinate, was significantly reduced by simultaneous exposure to an oily cream containing urea.55... 

Aluminum tubes are often used as the immediate package for dermal preparations. One important point to remember is that after the application of creams, ointments, or gels to the skin, all of the photo protection provided by the packaging is lost and photodegradation can occur. Topically applied drug substances with proven photoinstability, e.g., corticosteroids (36), retinoic acid (37), dithranol (38), and anti-mycotics (natamycine and nystatine) (39) fall into this category. 

Dithranol (an anthracene compound) is incorporated in a number of preparations, and is the most powerful drug presently used to treat chronic or milder forms of psoriasis in topical application. It is thought to work by inhibiting cell division (antimitotic) and may be used in combination with direct keratolytics. 

Dithranol is effective but has to be applied carefully to plaques of psoriasis avoiding normal skin, because it stains the skin violet-brown, leaving discoloration of healed areas. For this reason, and because it also stains clothing and bedding, patient compliance is poor with this drug. Its use is more successful with hospital inpatients and it has relatively few other side effects. 

A study in 19 healthy subjects found that the absorption of topical minoxidil was increased by almost threefold by the use of topical tretinoin 0.05% applied 1 hour before the minoxidil. The manufacturers note that topical drugs that alter the stratum corneum barrier, such as tretinoin or dithranol, could result in increased absorption of minoxidil if applied concurrently. They suggest that, theoretically, one possible effect of minoxidil absorption would be potentiation of orthostatic hypotension caused by vasodilator drugs. The exact drugs are not stated but this caution would be expected to cover drugs such as the nitrates and hydralazine. 

Guenther U, Smirnova 1, Neubert RH H (2(X)8) Hydrophilic silica aerogels as dermal drug delivery systems -Dithranol as a model drug. Eur Jo Pharmac Biopharmac 69 935 942... 

Dendrimers Synthetic Controlled and sustained drug delivery, bacterial infection, antiviral, vaccine and gene therapy Oncolytic agent Methotrexate,Paclitaxel, Docetaxel, Dithranol... 

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