1.4 Complex CSPs, Hazardous Drugs, and Testing

Parenteral nutrition

Parenteral nutrition (PN) is a sterile nutrition admixture that may contain amino acids, dextrose, lipids (IV fat emulsion), electrolytes, vitamins, trace elements, and other additives. PN is calculation-heavy and compatibility-sensitive, so the technician follows the verified formula, additive sequence, equipment instructions, and pharmacist verification exactly.

Key PN risks include calcium-phosphate precipitation, which can be fatal; emulsion cracking or destabilization in total nutrient admixtures; osmolarity that exceeds peripheral tolerance; wrong electrolyte concentration; and microbial or particulate contamination. A common safe-sequence rule adds phosphate early and calcium last, with adequate dilution and mixing between, and never adds them adjacently. Automated compounding devices (ACDs) improve measurement accuracy but do not replace line clearance, ingredient verification, tubing-setup checks, weight verification, or final inspection.

Specialized CSPs

Hazardous drug compounding (USP <800>)

Hazardous drugs (HDs) require controls protecting the product, worker, and environment. Use a containment primary engineering control (C-PEC, e.g., a Class II BSC or compounding aseptic containment isolator) inside a containment secondary engineering control (C-SEC) kept at negative pressure (typically 0.01-0.03 inches water column relative to adjacent areas). Withdraw from vials using negative-pressure technique to avoid spray, use closed system drug-transfer devices (CSTDs) for administration and when required during compounding, and keep a spill kit accessible.

A CSTD mechanically blocks environmental contaminants from entering and HD vapor or aerosol from escaping. It reduces exposure but does not replace the C-PEC, garbing, aseptic technique, or HD waste disposal.

Hazardous workflow checks

• Confirm the drug is on the facility HD list before it enters the workflow.
• Wear ASTM-tested chemotherapy gloves (double-gloved) and required PPE.
• Deactivate, decontaminate, clean, then disinfect HD surfaces in that order.
• Segregate trace and bulk HD waste per policy; PPE with residue is HD waste.

From nonsterile to sterile

Making a sterile preparation from nonsterile components is not a routine transfer; the process must address bioburden, particles, endotoxin risk, compatibility, and sterilization method. Steps may include dissolution, prefiltration to reduce particles, sterile filtration through a 0.22-micron sterilizing-grade filter for compatible solutions, terminal sterilization (e.g., steam autoclaving) when the product and container tolerate heat, and aseptic handling after sterilization.

Sterile filtration removes microorganisms but does not remove endotoxin, because endotoxin molecules are far smaller than the 0.22-micron pore, so the method must be justified and documented.

The choice between filtration and terminal sterilization is risk-based. Terminal sterilization (heat) is generally more robust because it sterilizes the product in its final sealed container, but many drugs and plastics cannot withstand autoclave temperatures, leaving sterile filtration as the practical option. A filter-integrity test (such as a bubble-point check) verifies the filter remained intact during use; a failed integrity test invalidates the sterility claim for that batch. Nonsterile-to-sterile compounding falls under the strictest <797> controls and frequently requires release testing before the CSP can be used.

Testing: sterility, potency, and endotoxin

Sterility testing detects viable microbial contamination under defined conditions. Potency testing verifies strength or concentration. Bacterial endotoxin testing (BET), commonly the Limulus Amebocyte Lysate (LAL) method, detects pyrogenic endotoxin that persists even after organisms are killed. Testing requirements depend on USP <797> category, batch size, ingredients, route, sterilization method, and assigned BUD — Category 3 CSPs in particular require sterility testing and, for injectables, endotoxin testing.

A passing test never excuses poor technique, and an out-of-specification result requires quarantine, investigation, and a documented disposition before any patient use.

Categories drive the testing and BUD decision

USP <797> sorts CSPs into three categories that dictate both beyond-use dating and release testing. Category 1 CSPs are compounded in lower-risk conditions and carry short BUDs. Category 2 CSPs are made under more controlled conditions and may earn longer BUDs depending on storage and sterility testing. Category 3 CSPs carry the longest BUDs and therefore demand the strictest controls — including sterility testing, and bacterial endotoxin testing for injectables, plus tighter personnel competency frequencies (every 3 months).

The technician's job is to recognize which category a preparation falls into so the right tests and dating are applied; assigning a Category 2 BUD to a product that did not meet Category 2 conditions is a documentation and patient-safety failure.

Result interpretation is binary at the gate: a CSP cannot be released on a pending or failed test. Because sterility and endotoxin results often return after compounding, high-risk batches are quarantined until results clear, and any out-of-specification finding triggers a formal investigation that may extend to other lots made under the same conditions.

Interpreting results

• Passing sterility supports release only when all other checks also pass.
• Failed sterility means the affected CSPs cannot be released without investigation.
• Potency outside limits may signal underdose, overdose, degradation, or compounding error.
• Endotoxin above the limit is especially critical for intrathecal, epidural, and IV routes.
• A Category 3 injectable requires both sterility and endotoxin testing before release.
• Any unexplained defect is documented and escalated before release.