| 摘要 |
The present invention relates to a method of treating acne or psoriasis by topically administering Tazarotene, a compound of formula (I), substantially free of dimer impurity 4,4-dimethyl-6-[4-(4,4-dimethyIthiochroman-6-yl)-buta-l,3-diynyl]-thiochromans a compound of formula (II) |
