Respiratory drug market dynamics

Bronchodilators use in patients with COPD

BACKGROUND

Bronchodilators are commonly used as maintenance and rescue therapy in patients with COPD. We aimed to examine the prescribing patterns of bronchodilators in clinical practice.

METHODS

We identified patients with COPD who initiated oral or inhaled bronchodilators between 2001 and 2010 from the Taiwan National Health Insurance Research Database. We followed the patients for 1 year. For bronchodilator prescriptions, we classified the treatments based on medication classes and regimens (oral bronchodilators alone, oral and inhaled bronchodilators in combination, or inhaled bronchodilators alone). For inhaled bronchodilator prescriptions, we further classified the treatments as short-acting bronchodilators alone, short-acting and long-acting bronchodilators in combination, and long-acting bronchodilators alone. We evaluated the prescribing patterns and the change with time, in different physician specialists, and in different hospital accreditation levels.

RESULTS

Among a cohort of 4,387 study-eligible patients, we identified 21,235 bronchodilator prescriptions for the analysis. The majority of prescriptions were oral xanthines or beta-2 agonists (62.63% and 47.54%, respectively) rather than prescriptions for inhaled bronchodilators (less than 10%). Nearly 80% of prescriptions were oral bronchodilator alone regimens. Use of oral bronchodilators declined with time and varied with health care providers, which were most commonly prescribed by non-chest specialists and in primary care clinics. Despite limited use of inhaled bronchodilators, it was noted that short-acting bronchodilators alone regimens accounted for 60% of the inhaled bronchodilator prescriptions.

CONCLUSION

Excessive use of oral and short-acting bronchodilators is noted in general practice. Further research and education programs are warranted to decrease inadequate oral bronchodilators and optimize inhaled treatments in the management of patients with COPD.

Effect of device design on the in vitro performance and comparability for capsule-based dry powder inhalers

This study investigated the effect of modifying the design of the Cyclohaler on its aerosolization performance and comparability to the HandiHaler at multiple flow rates. The Cyclohaler and HandiHaler were designated as model test and reference unit-dose, capsule-based dry powder inhalers (DPIs), respectively. The flow field, pressure drop, and carrier particle trajectories within the Cyclohaler and HandiHaler were modeled via computational fluid dynamics (CFD). With the goal of achieving in vitro comparability to the HandiHaler, the CFD results were used to identify key device attributes and to design two modifications of the Cyclohaler (Mod 1 and Mod 2), which matched the specific resistance of the HandiHaler but exhibited different cyclonic flow conditions in the device. Aerosolization performance of the four DPI devices was evaluated by using the reference product's capsule and formulation (Spiriva capsule) and a multistage cascade impactor. The in vitro data showed that Mod 2 provided a closer match to the HandiHaler than the Cyclohaler and Mod 1 at 20, 39, and 55 l/min. The in vitro and CFD results together suggest that matching the resistance of test and reference DPI devices is not sufficient to attain comparable aerosolization performance, and the improved in vitro comparability of Mod 2 to the HandiHaler may be related to the greater degree of similarities of the flow rate of air through the pierced capsule (Q(c)) and the maximum impact velocity of representative carrier particles (V(n)) in the Cyclohaler-based device. This investigation illustrates the importance of enhanced product understanding, in this case through the CFD modeling and in vitro characterization of aerosolization performance, to enable identification and modification of key design features of a test DPI device for achieving comparable aerosolization performance to the reference DPI device.