Non-Sting Medical Barrier Film Range Medi Derma-S Barrier Film provides long lasting barrier protection on mild/moderate skin damage. Medi Derma-S Barrier Film is a silicone-based, long-lasting, non-sting medical grade liquid which forms a protective uniform film when evenly applied to the skin. Its barrier properties protect damaged and intact skin from the harmful effects of moisture, irritants and from potential skin damage that may be caused from the application of adhesive wound dressings or pouches.