Pharmaceutical Dust Exposure at Pharmacies Using Automatic Dispensing Machines: A Preliminary Study

Abstract

Automatic dispensing machines (ADMs) used in pharmacies concentrate and dispense large volumes of pharmaceuticals, including uncoated tablets that can shed dust. We evaluated 43 employees’ exposures to pharmaceutical dust at three pharmacies where ADMs were used. We used an optical particle counter to identify tasks that generated pharmaceutical dust. We collected 72 inhalable dust air samples in or near the employees’ breathing zones. In addition to gravimetric analysis, our contract laboratory used internal methods involving liquid chromatography to analyze these samples for active pharmaceutical ingredients (APIs) and/or lactose, an inactive filler in tablets. We had to choose samples for these additional analyses because many methods used different extraction solvents. We selected 57 samples for analysis of lactose. We used real-time particle monitoring results, observations, and information from employees on the dustiness of pharmaceuticals to select 28 samples (including 13 samples that were analyzed for lactose) for analysis of specific APIs. Pharmaceutical dust was generated during a variety of tasks like emptying and refilling of ADM canisters. Using compressed air to clean canisters and manual count machines produced the overall highest peak number concentrations (19,000–580,000 particles/L) of smallest particles (count median aerodynamic diameter ≤ 2 μm). Employees who refilled, cleaned, or repaired ADM canisters, or hand filled prescriptions were exposed to higher median air concentrations of lactose (5.0–12 μg/m3) than employees who did other jobs (0.04–1.3 μg/m3), such as administrative/office work, labeling/packaging, and verifying prescriptions. We detected 10 APIs in air, including lisinopril, a drug prescribed for high blood pressure, levothyroxine, a drug prescribed for hypothyroidism, and methotrexate, a hazardous drug prescribed for cancer and other disorders. Three air concentrations of lisinopril (1.8–2.7 μg/m3) exceeded the lower bound of the manufacturer's hazard control band (1–10 μg/m3). All other API air concentrations were below applicable occupational exposure limits. Our findings indicate that some pharmacy employees are exposed to multiple APIs and that measures are needed to control those exposures.