Development and characterization of a scalable microperforated device capable of long-term zero order drug release

Abstract

A drug delivery system that consists of microperforated polyimide microtubes was developed and characterized. Two groups of polyimide tubes were used. One set consisted of microtubes (I.D. = 125 μm) with 32.9 ± 1.7 μm size holes. The second set consisted of larger tubes (I.D. = 1000 μm) with 362–542 μm holes. The number of holes was varied between 1 and 3. The small tubes were loaded with crystal violet (CV) and ethinyl estradiol (EE) and the drug release studies were performed in 0.01 M phosphate buffered saline (PBS) (pH 7.1–7.4) at 37.0 ± 1.0°C for upto 4 weeks. The large tubes were loaded with CV and the drug release was studied in vitro in PBS and also ex vivo in rabbit’s vitreous humor. Linear release rates with R2 > 0.9900 were obtained for all groups with CV and EE. Release rates of 7.8 ± 2.5, 16.2 ± 5.5, and 22.5 ± 6.0 ng/day for CV and 30.1 ± 5.8 ng/day for EE were obtained for small tubes. For large tubes, a release rate of 10.8 ± 4.1, 15.8 ± 4.8 and 22.1 ± 6.7 μg/day was observed in vitro in PBS and a release rate of 5.8 ± 1.8 μg/day was observed ex vivo in vitreous humor.