Effect of Unintentional Storage and Handling Errors of Inhaled Medications: What Does This Mean for Therapeutic Equivalence Considerations?

Evaluation of patients' real-world post-dispensing use and storage environments of tiotropium bromide Respimat® soft mist inhaler on its in vitro dose delivery and lung deposition

BACKGROUND

Oral inhalation is the main drug delivery route for treating obstructive lung conditions. Thus, many inhaler devices with various design and pharmaceutical formulation have been introduced. The fine particle dose (FPD) and mass median aerodynamic diameter (MMAD ≤ 5 μm) of the aerosol delivered dose (DD) dictate the therapeutically effective peripheral lung deposition. This study evaluated the in vitro aerosol emission performance of tiotropium bromide emitted from Spiriva® Respimat® soft mist inhalers (R) after living under patients' real-world, post-dispensing handling environments.

METHODS

This was a two-stage investigation. In the first clinical stage, research ethical approval was obtained to enrol patients already been using R for at least 3 months. Those who signed consent were given both new R to use and temperature and relative humidity (RH) handheld, portable data loggers to keep in the vicinity of the given R. The participants returned the given R and data loggers after 2 weeks. Patient recruitment took place in Amman, Jordan, during the summer (RS) and winter (RW). Subsequently, in the second laboratory stage, other R were strictly stored at an average of 21.0 °C and 46.9% RH as control (RC). The Next Generation Impactor (NGI) was used to evaluate the RS, RW and RC. The NGI was operated at a flow rate of 30 L/min.

RESULTS

The RS were exposed to an average (range) 23.6 °C (18.2-37.5 °C) and 43.8% RH (21.4-60.0% RH) that were statistically comparable (p > 0.05) to that of the RW; 17.3 °C (13.2-26.7 °C) and 52.8% RH (26.3-69.1% RH). The RW and RC retention environments were statistically different (p < 0.05), whilst the RS and RC had comparable (p > 0.05) conditions. No significant differences (p > 0.05) were found in the tiotropium bromide DD (2.39 vs 2.43 μg), FPD (0.88 vs 0.90 μg) and MMAD (5.1 vs 4.98 μm) between the RS and RW, respectively. Compared to the RC inhalers, both the RS and RW devices had significantly higher FPD and relatively smaller tiotropium bromide particles.

CONCLUSIONS

Using the R under the fluctuating summer and winter environments of our patients would not affect its overall tiotropium bromide emission performance. The significant increase in the respirable mass of the RS and RW might be offset by the increase in particles <1 μm particularly in patients with poor inhaler technique.

The impact of patients' real-life environmental temperature and humidity use conditions of tiotropium dry powder inhaler on its aerosol emission characteristics

INTRODUCTION

Many factors can affect dry powder inhalers' (DPIs) aerosol emission and lung deposition. The fluctuation of environmental temperature and relative humidity (RH) that inhalers experience in realistic daily use has not been extensively evaluated. This work aimed to evaluate the delivered dose (DD) and aerodynamic particle size distribution (APSD) of tiotropium Handihaler DPI (H) after exposure to patients' real-life use environments.

METHODS

Ethical approval was obtained to enrol adult patients already using H. Patients who gave written consent were given new H to use and HygroLog temperature and RH data loggers to keep in the vicinity of the given inhaler. The H and HygroLog were returned after 2 weeks. Patient recruitment was done during the summer (HS) and winter (HW). As control, other HC were stored as per the leaflet storage instructions. The Next Generation Impactor was used to evaluate the inhalers.

RESULTS

The HC were stored under an average of 21.0 °C and 46.9% RH. The patients' HS and HW lived in an average (range) temperature (°C) 23.2 (18.3-38.2) and 17.8 (13.5-24.6), respectively, and RH 50.8% (24.3-65.3%) and 50.4% (30.6-72.4%), respectively. All H groups had comparable environments (p > 0.05). The HC, HS and HW gave similar tiotropium DD (μg) 7.60, 8.01 and 7.61, respectively (p > 0.05). Moreover, the fine particle dose μg (median diameter (μm)) were HC 2.41 (3.84), HS 2.55 (3.81) and HW 2.37 (3.83) (p > 0.05).

CONCLUSIONS

The aerosol emission behaviour of tiotropium Handihaler was tolerant to real-life retention environments of patients in Amman, Jordan.