PROBLEMMultiple inpatient sterile compounded doses are prepared in "batches" in the majority of hospitals across the United States and the world.1 This is a process in which doses that are due at a given administration timeframe are prepared upfront in central or satellite institutional pharmacies to maximize operational and workflow efficiencies. The preparation of patient-specific sterile compounds is a time-consuming process that requires a great deal of attention to avoid any errors being introduced. The "batching" method is a prospective approach, where a hospital pharmacy produces several batches of medications that are tailored to the patients receiving them. There is normally a gap of several hours (or more) between the time of preparation and that of administration. During this gap, several variables can alter the intended use of dispensed medications. For example, doses might be discontinued or modified, patients might be transferred or discharged, or doses might be misplaced in the health care system requiring reproduction. These variables contribute to compounded sterile products (CSPs) being unused and eventually wasted, which costs the health care system unretrievable expenses.2 In many cases, the unused medications cannot be repurposed to other patients due to very specific dosing criteria (eg, weight-based doses) or beyond-use dating (BUD) issues. To minimize waste, an optimal balance between timely sterile compounded preparation (frequency) and personnel workload is necessary. Many studies were conducted of alternatives that might reduce the waste of sterile compounded products and doses.2-5 A review of the current literature 3,[6][7][8][9][10] suggests that the well-established practice of lean intravenous (IV) methodology had a positive effect on pharmacy efficiency as ABSTRACT Purpose: To measure the impact of increasing sterile compounding batch frequency on pharmaceutical waste as it relates to cost and quantity. Methods: Pharmaceutical IV waste at a tertiary care hospital was observed and recorded for 7 days. The batching frequency of compounded sterile products (CSPs) was then increased from twice daily to 4 times daily. After a washout period, pharmaceutical IV waste was then recorded for another 7 days. The quantity of units wasted and the cost were compared between both phases to determine the impact that batching frequency has on IV waste, specifically among high-and low-cost drugs. Results: Patient days increased from 2,459 during phase 1 to 2,617 during phase 2. The total number of CSPs wasted decreased from 3.6 to 2.7 doses per 100 patient days.