Danderine was advertised as early as 1889 without the name Knowlton's associated with it. I am not sure whether it was the same product or if Knowlton just took the name. According to Urquhart Knowltoin's Danderine was invented (1895) and patented (1908) by Sterling Products, of Ontario. The box on a later variant (3) mentioned the Sterling Products (Inc.) of Chicago and Wheeling, W.V. Knowlton's Danderine Co. itself was listed in Chicago from 1898 until 1909. It was probably then that they were bought out by Sterling Products. Danderine was still for sale at least as late as 1922 in the Montgomery Wards Catalog.
According to the label, the Danderine was 9% alcohol. The label also mentioned the Pure Food and Drug Act of 1906.
There was an awesome write up in The New England Magazine called Greater Industries of America - A Brief History of Danderine. In this article, it says Danderine started in 1901 in Oklahoma. In the article they state that the product was invented by Dr. E. W. Knowlton. They said the company eventually moved to Chicago and added several other products. Apparently at one time Hoagland Drug Co ordered $55,000 worth and McKesson & Robbins ordered $30,000 worth.