Several years ago a friendly looking young man walked into my office at the University Department of Dermatology in Cologne, introduced himself as a diplomate chemist, executive member of a family-owned, rather small German company manufacturing hair care products, and proposed to me straight forward to organize an international meeting on hair research. In view of the large number of new developments in the field something like this should be done after all, he said; he also promised to provide financial support. Such a meeting should be on the highest possible level, I said; and he agreed. I took the challenge and my visitor kept his promise. Three years later the First International Hair Congress was organized at the sophisticated new Congress Center in Hamburg, in which 630 participants from 36 countries were registered. After three and a half days of formal sessions, informal discussions, workshops and poster presentations our unanimous feeling was that this has been a most successful meeting. The young chemist was right. The idea was excellent. The growth and presence of hair and its distribution over the human body as a cosmetic attribute has become during the last two decades a matter of tremendous emotional significance. Hair can be rather easily formed according to one's sence of style, representing his personal image and his social feeling. If it becomes unacceptable or out of fashion, the hair style can be easily changed; the hair regrows as a biological requisite, without any additional cost.

With the aromatic retinoic acid analog Tigason oral and intravenous pharmacokinetic studies have been performed in 5 normal volunteers. Simultaneous fitting of single i. v. and oral data to a three-compartment model assuming first-order absorption was possible. Using Nonlin parameter estimates of the single-dose data, one is able to predict the decline in plasma levels of parent drug following cessation of a 10 days multiple dosing regimen up to 24 hours. The model is however unable to predict a phase of prolonged elimination observed beyond 24 hours. Moreover in 5 patients, who underwent chronic therapy (8-15 months), substantial plasma levels of both unchanged drug and main metabolite (corre sponding carboxylic acid) were observed up to 140 days after cessation of the therapy. An apparent half-life of elimination of 80-100 days can be calculated. The drug appears to be stored at some yet unknown storage site. Investigation of metabolism of Tigason in rats and humans revealed 19 different bio transformation products thus far, most of them appearing in the urine in low amounts (20010 of dose). A few of them (mainly the acid Ro 10-1670) after conjugation to glucuronic acid are excreted in the bile in high amounts (60-80% of dose). No drug appeared unchanged in the excreta after i. v. administration to rats. References 1. Bollag W (1971) Effects of vitamin A acid (NSC-122758) on transplantable and chemically-induced tumors. Cancer Chemother Rep 55:53-58 2."