Development of an inhaled ion-paired salbutamol formulation

Bridie Dutton, Arcadia Woods, Robyn Sadler, Nathalie Fa, Ben Forbes, Stuart Jones

Ion-pairing is a promising technique to control drug delivery that has been shown to be effective for both transdermal and oral medicines. This strategy could also be very interesting for inhaled formulations as it has the potential to control the delivery of a drug without changing the structure of the molecule. Previously, salbutamol has been shown to bind the negatively charged counter ions sodium sulfate, gluconate and octanoate with varying degrees of strength. However, to administer these ion-pairs to the lung an inhalable formulation must be developed. Spray drying is an attractive method to engineer particles for an inhalable formulation as it allows the control of particle size, which influences lung deposition. In this study spray dried ion-pair formulations were developed using lactose, as the bulking agent, PVP, as a physical stabilizer, and l-leucine, to improve powder dispersion. In vitro deposition studies with the spray dried formulations using the Next Generation Impactor demonstrated that the gluconate and octanoate ion-pairs improved the dispersibility of the salbutamol microparticles. The addition of PVP to the microparticles generally increased their size except for the octanoate formulation, which produced a smaller particle and better dispersion. The addition of l-leucine generally improved the dispersibility of the powders, but it didn’t affect the particle size, hence resulted in a smaller MMAD in comparison to the counter ion/PVP formulations. The results of this study show that it is possible to make an ion-pair formulation that is suitable for inhalation.

Join today to view and download the full abstract/presentation