USP <643> - Total Organic Carbon

What it says

General Chapter <643> describes methodology for measuring total organic carbon in pharmaceutical waters, used as an indicator of organic contamination that could arise from source water, system materials, or microbial activity within the water system.

Paraphrased for plain-language clarity. Always verify against the current published regulation text.

What it means in practice

• Total organic carbon testing serves as a general indicator of organic contamination rather than identifying specific contaminants, functioning as an early-warning screening tool within the broader pharmaceutical water quality control programme described in USP <1231>.
• This test is typically performed together with conductivity testing under Chapter <645>, since the two together provide complementary chemical quality indicators for pharmaceutical water without requiring exhaustive testing for every possible individual contaminant.
• Online, continuous total organic carbon monitoring is increasingly used for pharmaceutical water systems, allowing real-time detection of an organic contamination excursion rather than relying solely on periodic grab-sample testing.

What inspectors look for

• Whether total organic carbon monitoring frequency and methodology, online continuous or periodic grab-sample, is appropriate for the specific water system and its actual risk profile.
• Whether total organic carbon data is trended over time to detect gradual increases, not evaluated only against a specification limit at each individual measurement.
• Whether an excursion in total organic carbon triggers appropriate investigation into potential system-level causes, such as biofilm formation or material degradation.

Related regulations