Loading...
2 results
Search Results
Now showing 1 - 2 of 2
- A poly(ε-caprolactone) device for sustained release of an anti-glaucoma drugPublication . Natu, Mădălina; Gaspar, Manuel; Ribeiro, Carlos; Correia, Ilídio Joaquim Sobreira; Silva, Daniela; Sousa, Hermínio C. de; Gil, MariaImplantable dorzolamide-loaded discs were prepared by blending poly(ε-caprolactone), PCL, with poly(ethylene oxide)-b-poly(propylene oxide)-b-poly(ethylene oxide), Lu. By blending, crystallinity, water uptake and mass loss were modified relative to the pure polymers. Burst was diminished by coating the discs with a PCL shell. All samples presented burst release except PCL-coated samples that showed controlled release during 18 days. For PCL-coated samples, barrier control of diffusion coupled with partition control from the core slowed down the release, while for 50/50 Lu/PCL-coated samples, the enhancement in the porosity of the core diminished partition control of drug release. Nonlinear regression analysis suggested that a degradation model fully describes the release curve considering a triphasic release mechanism: the instantaneous diffusion (burst), diffusion and polymer degradation stages. The MTT test indicated that the materials are not cytotoxic for corneal endothelial cells. A good in vitro–in vivo correlation was obtained, with similar amounts of drug released in vitro and in vivo. The discs decreased intraocular pressure (IOP) in normotensive rabbit eyes by 13.0% during 10 days for PCL-coated and by 13.0% during 4 days for 50/50 Lu/PCL-coated samples. The percentages of IOP decrease are similar to those obtained by dorzolamide eyedrop instillation (11.0%).
- Preparation and chemical and biological characterization of a pectin/chitosan polyelectrolyte complex scaffold for possible bone tissue engineering applicationsPublication . Coimbra, Patrícia; Ferreira, Paula; Sousa, Hermínio C. de; Batista, Patrícia Sofia Pinhanços; Rodrigues, Miguel; Correia, Ilídio Joaquim Sobreira; Gil, MariaIn this work, porous scaffolds obtained from the freeze-drying of pectin/chitosan polyelectrolyte complexes were prepared and characterized by FTIR, SEM and weight loss studies. Additionally, the cytotoxicity of the prepared scaffolds was evaluated in vitro, using human osteoblast cells. The results obtained showed that cells adhered to scaffolds and proliferated. The study also confirmed that the degradation by-products of pectin/chitosan scaffold are noncytotoxic.