Oral dose preparation at pharmacies: evaluation of pharmaceutical dust exposure

Pharmaceutical tablets, especially uncoated tablets, can shed dust. This dust is a potential source of inhalation exposure for pharmacists and pharmacy technicians if work tasks or processes take place that aerosolize the dust. Health effects from exposures to multiple pharmaceuticals over a working lifetime, as could be encountered in a pharmacy setting, are not well understood. Some oral pharmaceuticals are included on the NIOSH List of Hazardous Drugs, are highly potent, or have special handling requirements. Production of these “specialty” oral drugs appears to be increasing. We embarked on a study to assess inhalation exposure to pharmaceutical dust at three outpatient pharmacies. Automatic dispensing machines were used at each pharmacy to fill between 2,000 and 14,000 prescriptions per day. We evaluated 43 employees’ exposures to pharmaceutical dust by collecting a total of 72 inhalable dust air samples in the employees’ breathing zones. We selected 57 of the samples for analysis of lactose. We used real-time optical particle monitoring results, observations, and information from employees on the dustiness of pharmaceuticals to select 28 samples for the analysis of specific active pharmaceutical ingredients (APIs). We found that pharmaceutical dust was released into employees’ breathing zones during the following tasks: emptying, refilling, and cleaning of automatic dispensing machine canisters, and hand filling of oral prescriptions. Employees who did these tasks were exposed to higher median air concentrations of lactose (5.0 – 12 µg/m³) than other pharmacy employees (0.04 – 1.3 µg/m³). In addition to lactose, we detected multiple APIs in air including lisinopril, levothyroxine, and methotrexate; the latter of which is on the NIOSH List of Hazardous Drugs. These findings suggest that pharmacy employees can be exposed to multiple APIs during specific tasks. During this presentation, we will also present our particle size measurements of pharmaceutical dust released during specific tasks, which will influence lung deposition, transport, and residence time of particles in air. Lastly, we will discuss possible control measures that can be used to minimize pharmaceutical dust exposures.