example the host the mode of administration and the nature and severity of the condition being treated however in general satisfactory results are indicated to be obtained systemically at daily dosages of from about 0 15 mg kg to about 1 5 mg kg animal body weight for the larger mammal an indicated daily dosage is in the range from about 0 01 mg to about 100 mg of a compound of formula i conveniently administered for example in divided doses up to four times a day for topical use satisfactory results are obtained with local administration of a 1 3 concentration of active substance several times daily e g 2 to 5 times daily examples of indicated galenical forms are lotions gels and creams the compound of the invention may be administered by any conventional route in particular enterally e g orally e g in the form of tabiets or capsules or topically e g in the form of lotions gels or creams pharmaceutical compositions comprising a compound of formula i as defined above in association with at least one pharmaceutical acceptable carrier or diluent may be manufactured in conventional manner by mixing with a pharmaceutically acceptable carrier or diluent unit dosage forms contain for example from about 0 0025 mg to about 50 mg of a compound of formula i topical administration is e g to the skin a further form of.