In this paper recent patents in pressurised metered dose inhalers have been reviewed. The patents are related to novel valves, dose-counters, formulations, add-on devices, reduction of propellant leakage and inkjet technology. Recently patented dose-counters provide mechanisms that
are less susceptible to inaccuracy, and are battery-less electronic dose-counters with the help of miniature electromechanical generators. Regarding the formulation aspect, recent patents provide methods for combinational pMDIs and more stable products. Advantages of recently patented valves
are being spring-free and less subject to loss of prime. Recent developments in micromachining have allowed patents that incorporate inkjet technology to develop inhalers that are similar to pMDIs, but produce uniform aerosol droplets. Coating canisters with suitable polymers has reduced need
for excipients. Recently patented add-on devices reduce aerosol deposition in the spacer by creating turbulence on the walls of the chamber. Blockage of nozzles in actuators is prevented by providing tapered nozzle channels. In conclusion, these patents show better understanding of pMDIs and
provide methods to achieve products with much improved reliability, aerosol performance and stability.
Recent Patents on Drug Delivery and Formulation publishes review articles by experts on recent patents on drug delivery and formulation. A selection of important and recent patents on drug delivery and formulation is also included in the journal. The journal is essential reading for all researchers involved in the fields of drug delivery and formulation.