Maintaining a fixed distance during coating of drug coated balloon

A method of coating an expandable member of a medical device, comprising:

• providing an expandable member having an inflated configuration, wherein the expandable member is transversly displaceable along its length in the inflated configuration;
• providing an applicator in fluid communication with a fluid source, the applicator having at least one outlet for applying fluid therefrom;
• positioning the applicator proximate a surface of the expandable member in the inflated configuration;
• establishing relative movement between the at least one outlet and the surface of the expandable member along a coating path;
• maintaining a substantially fixed distance between the at least one outlet and the surface of the expandable member during relative movement therebetween by externally constraining transverse displacement of the expandable member proximate the at least one outlet during relative movement therebetween;
• and
• applying fluid from the at least one outlet to form a direct coating of fluid on the surface of the expandable member along the coating path.