Up to five per cent of patients reported having trouble removing the release liner from the sticky part of Daytrana (methylphenidate transdermal system) patches, which are used for the treatment of ADHD. While the mechanics did not affect the release of the drug, Shire decided to take the "proactive step" to withdraw the product. The UK company, which has the global license for Daytrana, said in a statement the patches could continue to be used as long as they were not damaged. Meanwhile, Noven and Shire, in the first quarter of this year, implemented enhancements to the Daytrana release liner by increasing the release coating on the liner to provide an easier removal. The improved patches would replace those being withdrawn, which are Daytrana packages with an expiration date of March 31, 2009 or earlier, and Daytrana packages with lot numbers 2563511, 2563611, 2570411. The withdrawal was not believed to have any affect on either Shire or Noven or on the patches' manufacturing, Shire spokeswoman Jessica Mann told in-PharmaTechnologist.com. The withdrawal should cost less than $10m (€7.35m), according to a report by Reuters. Daytrana, developed and manufactured by Noven, was approved in the US by the FDA last year, and is the first and only transdermal medication approved to treat the symptoms of ADHD. It is approved for children aged six to twelve years with the disorder. Since its approval, an estimated 700,000 patches have been sold, with last year's sales to Shire totalling $8.6m, with $5.9m recognized in related license revenues. At the end of July, Shire's net sales of Daytrana exceeded $50m in the 12-months preceding June 30, 2007, triggering a $25m milestone payment to Noven. The product is based on Noven's proprietary DOT Matrix transdermal technology, which the company claims has significant advantages over standard patch products. The system uses a patented multiple adhesive mix of silicone, acrylic and the required drug so that the drug is mixed in with the adhesive that holds the patch on the skin. Each patch is a thin, three-layer laminate made up of the patch backing, the drug/adhesive mix and the release liner (the part that gets peeled off and thrown away once the patch is applied). The patches themselves are compatible with a wide range of medications, and as they deliver the drug more effectively than other competing products they tend to be smaller than other transdermal systems. In addition to this, the patches use one adhesive to hold the drug, and another to make the patch stick to the skin, resulting in superior adhesion to the skin. The Noven transdermal system is already in use in other products beyond Shire's ADHD patch, including DentiPatch (a transmucosal patch for dental pain), Vivelle-Dot (the world's smallest transdermal estrogen patch), and a number of other hormone therapy patches. In June, Shire acquired development rights to a new transdermal patch product for ADHD, using amphetamine, after Shire and Noven decided to proceed with clinical development of the patch. According to Noven, amphetamine products represent about half the US market for stimulant ADHD therapies, and a patch product could bring significant advantages to patients and enhance compliance.