7.1 Compounding Equipment & Technology: ACDs, Balances, Pumps & IV Workflow Systems

7.1 Compounding Equipment & Technology: ACDs, Balances, Pumps & IV Workflow Systems

Modern sterile compounding depends on machines: automated compounding devices (ACDs) for parenteral nutrition, repeater pumps for batching, analytical balances, IV workflow software and, increasingly, robots. The BCSCP outline (task 1A2) expects you to choose them, qualify them, place them correctly and supervise their daily checks.

USP <797> baseline for all equipment (Section 9.1)

• Equipment brought into classified areas is wiped with a sporicidal disinfectant, an EPA-registered disinfectant, or sterile 70% IPA using low-lint wipers.
• It is placed so that it helps sterile work. Inside a PEC, placement is verified with a smoke pattern test (see 2.5).
• It must operate properly and within its performance parameters.
• Personnel follow SOPs for calibration, maintenance, cleaning and use, based on the manufacturer's recommendations.
• Records of calibration, verification and maintenance are kept as documentation under Section 20.

Automated compounding devices (ACDs)

ACDs pump several source solutions into a final container under computer control. They are standard for PN and are also used for cardioplegia and batch admixtures.

USP <797> requirement: before first use, and again each day it is used to compound CSPs, personnel perform an accuracy assessment. They keep a daily record of the accuracy measurements. Precision is tracked by looking at day-to-day variation in accuracy. If measurements fall outside the manufacturer's specification, corrective action is taken.

Typical good practice around that requirement:

Worked gravimetric check

A channel is programmed to deliver 100.0 mL of dextrose 70% (specific gravity about 1.24).

$$\text{Expected mass} = 100.0\,\text{mL} \times 1.24\,\text{g/mL} = 124.0\,\text{g}$$

The balance reads 122.3 g, so the delivered volume is $122.3 \div 1.24 = 98.6$ mL, which is $1.4\%$ low. Whether that passes depends on the manufacturer's accuracy specification. Record the result, and if it is out of specification, take the channel out of service and correct it.

Balances (USP <41> and <1251>)

Weighing nonsterile APIs for Category 2 and 3 CSPs, and gravimetric checks, depend on the balance. USP <41> has two tests:

• Repeatability: weigh a test weight at least 10 times. The balance is suitable for a weighing if

$$\frac{2 \times s}{m} \le 0.10\%$$

where $s$ is the standard deviation and $m$ is the smallest net weight to be weighed. If $s$ is below $0.41d$ (where $d$ is the readability), $0.41d$ is used instead.

• Accuracy: a calibrated test weight between 5% and 100% of capacity must read within 0.10% of its value.

Minimum weight example: readability $d = 0.1$ mg, so $0.41d = 0.041$ mg, and the measured $s = 0.05$ mg. Because $s$ is larger than $0.41d$, use $s$:

$$m_{\min} = \frac{2 \times 0.05\,\text{mg}}{0.0010} = 100\,\text{mg}$$

Weighings below 100 mg on this balance are not reliable. Use a more precise balance, or use an aliquot method. USP <1251> covers placement (a stable surface away from drafts and vibration), daily checks, and weighing inside containment for hazardous powders.

Repeater pumps and syringe fillers

Peristaltic or syringe repeater pumps fill many syringes or bags with the same volume. Verify the programmed volume gravimetrically at the start of each batch and at intervals during long runs. Prime the sterile tubing set and account for its dead volume. Label the source container on the pump clearly to prevent mix-ups.

IV workflow management systems (IVWMS)

An IVWMS guides the technician step by step. It scans the barcode of every component, may weigh additions (gravimetric verification), photographs key steps, calculates volumes and builds an electronic compounding record. This lets the pharmacist verify remotely from images and data rather than from a syringe pulled back to the dose line.

ISMP's guidelines for safe preparation of compounded sterile preparations recommend moving away from syringe pull-back checking. That method cannot show what was actually injected, from which vial, or whether it was drawn once or twice. Technology-assisted checks are preferred. USP <797> allows the compounding record to be stored electronically in ACD or workflow systems, as long as it is retrievable and contains the required elements.

Robotics

Compounding robots, whether self-contained or placed inside a PEC, need:

• a dynamic smoke pattern test initially and at least every 6 months (USP <797> 4.2.3);
• validated cleaning, including a sporicidal step;
• for Category 3, surface sampling at least daily at the end of operations if the robot is a self-enclosed device;
• documented dose-accuracy verification and downtime procedures.

Other equipment to keep under control

• pH meters: calibrate with standard buffers on each day of use.
• Refrigerators, freezers and incubators: monitor temperature continuously or at least daily, and verify the monitoring devices every 12 months if the manufacturer gives no interval. Incubators must sit outside the sterile compounding area.
• Air samplers and particle counters: service and calibrate them as the manufacturer recommends.
• Autoclaves and depyrogenation ovens: use a calibrated recorder on each cycle, and biological indicators or endotoxin challenge vials as described in 6.1.