The present invention provides a novel method for monitoring the surface concentration of a drug in a polymer blend matrix and the reaction kinetics of the biodegradable polymers. The controller includes a circuit interface, an address decoder coupled to the circuit interface, a plurality of sub-circuits, wherein each sub-circuit includes registers used to configure and control the sub-circuit, and a bus that couples the registers of each sub-circuit to the address decoder. The nose filter mounting device also includes first and second filter magnets connected to the first and second septum magnets, respectively, each filter magnet being configured to mate with filter elements in the nostrils of the user. Both comparisons are repeated over many calculations and the differences analyzed to reliably determine whether there is a real restriction to recirculated exhaust flow.