Perfluorohexyloctane (F6H8) as a delivery agent for cyclosporine A in dry eye syndrome therapy - Langmuir monolayer study complemented with infrared nanospectroscopy.

One of the key challenges in dry eye syndrome therapy is to find a suitable carrier for immunosuppressant drug - cyclosporine A (CsA) - delivery to the eye. To investigate this issue, herein we present a methodology based on the combined analysis in macro- (Langmuir monolayers), micro- (Brewster angle microscopy) and nanoscale (atomic force microscopy and infrared nano-spectroscopy). The applied approach proves that CsA affects the phospholipid part of the tear film lipid layer by loosening molecular packing. This effect can be reversed by the addition of perfluorohexyloctane (F6H8). We have highlighted that F6H8 increases the availability of CsA and therefore is appropriate carrier for CsA topical delivery to the eye in the dry eye syndrome. In addition, the applied herein procedure provides a simple, low-cost laboratory tool for preliminary studies involving membrane active pharmaceuticals, preceding in vivo tests.