Implementation and Qualification of a Dual Activated Carbon Filtration System for Persistent GMP-Compliant Water Purification

Abstract

Activated carbon filters are essential in pharmaceutical water systems, ensuring removal of chlorine, organic matter, and microbial contaminants. Modernization of legacy systems is critical to maintain compliance with pharmacopeial and GMP requirements. This study describes the upgrade of a dual activated carbon filter system, replacing a partially modernized unit with stainless steel construction and automated Human–Machine Interface (HMI) controls, and evaluates its impact on purified water quality. The system was qualified under structured change control following DQ, IQ, OQ, and PQ protocols. Sixty determinations of physicochemical and microbiological parameters were performed, including conductivity, nitrates, total organic carbon, residual chlorine, and microbial counts. Sampling was conducted upstream and downstream of the ACF units, with analyses aligned to USP and European Pharmacopoeia standards. Residual chlorine was consistently removed, with outlet concentrations <0.1 mg/L. Total organic carbon values ranged from 15.4 to 179 ppb, remaining below the alert limit of 200 ppb. Conductivity and nitrate concentrations met USP requirements across all determinations. Microbiological assays showed colony counts below alert thresholds (maximum 15 cfu/mL), with no pathogenic microorganisms detected. Hot‑water sanitizations at 80 °C, should be three time per week, effectively controlled microbial growth, supported by the enhanced durability of stainless‑steel piping. The upgraded dual activated carbon filter system demonstrated robust compliance with pharmacopeial standards, improved operational reliability, and sustained water quality. Modernization strategies, executed under GMP and ICH Q10 change control, proved essential for risk mitigation, reproducibility, and long‑term sustainability of pharmaceutical water systems.