The movement of drug across a micro channels in a manner driven solely by the concentration gradient. Flow field reached at the end of the channel within 38 seconds. Fully developed flow, with sustainable

diffusion rates, occurred at approximately 150 seconds. The results of drug diffusion at 50 seconds through various microchannel Inhibitors,research,lifescience,medical selleck chemicals configurations considered are shown in Figure 6. It is interesting to note that different microchannel configurations will give rise to different diffusion rates. The drug diffusion rate as a function of time for various microchannel configurations is presented in Figure 7. It can be seen from Figure 7 that each of the microchannel configurations exhibits different diffusion characteristics in terms of drug diffusion rates. Initially, there is a drastic increase and after a certain time, the diffusion rate is almost constant. Inhibitors,research,lifescience,medical If the drug was to be delivered at a constant rate over a one-hour period then the inlet flux of straight microchannel would be 6.25 × 10−12kmol/s. Over the first second, there is a rapid increase of diffusion rates up to approximately 1.24 × 10−13kmol/s and then a more gradual increase to approximately 6 × 10−12kmol/s after 105 seconds. Overall, each of the microchannel configurations can deliver the drug at different diffusion rates. Figure 5 Simulation

results of drug diffusion through a straight-type Inhibitors,research,lifescience,medical microchannel configuration. Figure 6 Simulations of drug diffusion at 50 seconds through various microchannel configurations. Figure 7 Diffusion rate for various Inhibitors,research,lifescience,medical microchannel configurations considered. Based on the results obtained through various microchannel configurations, the designs: osmotic I and osmotic II best

satisfied the diffusion rate specifications (less than 0.07nL/min) for the developed ocular drug delivery device. These results are presented in Figure 8. In order to demonstrate the diffusion through the entire device, Inhibitors,research,lifescience,medical an analysis is carried out using the osmotic II microchannel and the reservoir for 1500 seconds using ANSYS software. It is assumed that the thermal conductivity and specific heat and density were set as 0.6W·m−1·K−1, 4181.3J/kg·K, and 850Kg/m3, respectively, for simulating the diffusion through the device. No thermal conduction is considered at the surrounding wall of a device. The temperature those of 120°C at the inlet (center top of reservoir) and 37.5°C at the outlet is applied for this simulation. The result of diffusion at various times is shown in Figure 9. It can be seen from Figure 9 that a very slow diffusion occurs most likely at the narrow channel paths. This demonstrates that the developed microdevice is capable of delivering the drug through the osmotic II microchannel configuration. Figure 8 Diffusion rate comparisons at different times through the microchannel designs (osmotic I and osmotic II) for ocular drug delivery applications.