Background: Oseltamivir Phosphate (OP) is an ethyl ester prodrug prescribed for the treatment
of influenza virus infection. Current marketed formulations of OP have been observed to be supplemented
with an adverse effect during post-marketing surveillance. These prerequisites are sufficed
by developing a sustained release Dry Powder for Inhalation (DPI).
Objective: The objective of the present study was to develop OP-DPI by an innovative formulation
approach comprising of Immediate (IR) and Sustained (SR) Release portions.
Methods: DPI formulation comprising IR and SR portions were prepared by spray drying technique
using Hydroxy Propyl Methyl Cellulose (HPMC) as the rate-controlling polymer for SR portion. The
spray-dried product was further characterized for various pharmaco-technical, in-vitro and in-vivo parameters.
Results: OP-DPI showed a burst release of 49% within 15 min further sustaining the drug release up to
9 hrs. The in-vitro aerodynamic performance of OP-DPI showed maximum deposition at stage 3 and
Fine Particle Dose (FPD) of 1.08 mg indicating deposition in the upper respiratory tract. Solid-state
characterization by DSC and XRD indicated the partial amorphization of OP due to spray drying. In-vivo
toxicological examination revealed no sign of inflammation, indicating the safety of the developed
formulation. Accelerated stability study as per ICH guidelines displayed no significant change in the
solid-state characterization and drug-related performance of OP-DPI.
Conclusion: Prepared novel and scalable OP-DPI may have the potential to overcome the problems
associated with existing marketed dosage forms of OP. Further, localized drug delivery of the antiviral
drug through the pulmonary route might be clinically beneficial in controlling the viral proliferation.