Bayer MaterialScience has developed a new line of drug-releasing coatings under the trade name Baymedix® CD. By carefully balancing the ratio of hydrophobic to hydrophilic elements, these coatings can be customised to achieve different release rates of the drug they contain.

Baymedix® CD is widely tunable, allowing the target drug to be completely released in as little as a few hours, or up to several months. The tunability also means a range of active substances can be released, from small molecule drugs to biopharmaceuticals. Release kinetics are first-order with little or no burst effect.

The coatings are suitable for many demanding applications. Baymedix® CD coatings are available for both rigid and flexible substrates, allowing them to be used, for example, on expandable stents. The smooth, uniform appearance of the coatings, applied by spraying or dipping, is an additional benefit. Baymedix® CD technology has been developed primarily with an eye on the market for medicine-coated stents, but collaborations are already under way with manufacturers of a variety of drug-releasing medical devices.

Although it can also be coated onto polymeric substrates, the coating has principally been engineered to provide good adhesion to metals like stainless steel and nitinol. The process for coating a medical device involves a surface activation step, an additional surface modification step, and then application of the coating along with the drug. The surface modification allows a covalent bond to form between the substrate and the coating, giving excellent, long-lasting adhesion.

Baymedix® CD’s suitability for implantation has been demonstrated by 28-day and 90-day porcine coronary artery tests. Additional biocompatibility tests support the inertness of these coatings. They can be sterilized by means of gamma irradiation or ethylene oxide..