The drug-releasing hollow fiber and hollow fiber patch

Abstract

Purpose. To develop a new drug delivery system made of hollow fiber fabric. We report preliminary in vitro results of drug-impregnated hollow fiber and hollow fiber fabric. Methods. (1) Impregnation of chemicals into the hollow space: Dacron hollow fiber (T-334W, 1 hole with 15% void, 5.5 Denier per filament, DuPont, USA) was submerged in the liquid solution and placed inside a vacuum chamber (−30 Torr, 5 min). The fiber was examined by microscopy. (2) Hollow fiber model: 4 g of 3.81-cm-long Dacron hollow fiber was impregnated with solutions (150 ml of 5 M NaCl and 40,000 IU/150 ml of low molecular weight heparin (Fragmin, Pfizer, NY, USA)) as mentioned above. They were placed in room air for 48 h to be dried and placed in 200-ml distilled water at 37°C. The cumulative conductivity was measured for 4 weeks. (3) Fabric model: a knitted patch (5 × 30 mm) made of hollow fiber was impregnated with 10,000 IU/3 ml of Fragmin as mentioned above. The cumulative conductivity was measured in 50 ml distilled water for 4 weeks. The concentration of solution and the rate of emission were calculated with calibration curve of each chemical. Results. (1) Under microscopy, fibers filled with liquid looked clear, although un-removed air remaining in the hollows appeared as dark streaks. (2) The cumulative release kinetics were curve-fit as follows: NaCl (mol) = 1.91 Ln( t) + 13.5 ( R 2 = 0.879); Fragmin (IU) = 825.6 Ln( t) + 10010 ( R 2 = 0.81), where t is time measured in days. The amount of NaCl or Fragmin released in each time interval decreased over time until day 4 or 5 and is thereafter relatively constant and zero order. The cumulative amount released of NaCl and Fragmin at day 28 was 18.9 mol and 12,174 IU. (3) In patch model, the results were almost the same as the fiber model. The cumulative released Fragmin (IU) = 18.0 Ln( t) + 57.4 ( R 2 = 0.92) (125 IU at day 28). The emission rate decreased over time until day 4 and is thereafter relatively constant: rate (IU/day) = 18.0/ t. Conclusions. It was confirmed that chemicals were impregnated into hollow space with a vacuum chamber and they were released continuously from the hollow fiber and hollow fiber fabric models for more than 2 weeks. This new drug delivery system would be useful as an artificial patch or a graft in the field of cardiac or vascular surgery.