Clinical equivalence of budesonide dry powder inhaler and pressurized metered dose inhaler

Abstract

A delivery device is the most important factor that determines the local/systemic bioavailability of inhaled corticosteroids. Dry powder inhalers (DPIs) and pressurized metered dose inhalers (pMDIs) are the most commonly used delivery devices for localized drug delivery to the airways. This study was to compare the clinical equivalence of budesonide delivered by the Pulmicort Turbuhaler (DPI) and the Aeronide inhaler (pMDI). The two inhalers were compared for their pharmaceutical equivalence and clinical equivalence. The in vitro test included the uniformity of the delivered dose and determination of the aerodynamic particle size of budesonide. The in vivo test was carried out in 36 patients with mild to moderate asthma. This was a randomized, single-blinded study conducted for a period of 3 months. This included assessment of the spirometric parameters [forced expiratory volume in 1 s (FEV1), forced vital capacity (FVC), peak expiratory flow rate (PEFR), forced expiratory flow 25-75% (FEF25-75)], the severity of asthma symptoms, adverse events, frequency of short-acting inhaled bronchodilator usage and measurement of urinary cortisol levels. The aerodynamic particle size was slightly different between the two inhalers (2.3 ± 0.2 µm for Pulmicort Turbuhaler and 2.2 ± 0.2 µm for Aeronide inhaler). Both inhalers passed the uniformity of delivered dose (95.4% and 97.4%) specified in the British Pharmacopoeia. There was no statistically significant difference observed between the two inhalers in terms of the spirometric parameters, symptom-free days, frequency of bronchodilator usage and the level of urinary cortisol. In addition to pharmaceutical equivalence, no clinical difference observed between the two budesonide inhalers.