Overview
ISO 4802-2:2023 - Glassware - Hydrolytic resistance of the interior surfaces of glass containers - Part 2: Determination by flame spectrometry and classification describes a standardized laboratory method to evaluate how the inner surfaces of glass containers resist hydrolytic attack by water. The test uses controlled heating (121 ± 1 °C for 60 ± 1 min) and quantifies released alkali/alkaline‑earth species (notably sodium) in the extraction solution by flame atomic emission or absorption spectrometry (flame spectrometry). The document also defines a classification system (HC 1, HC 2, HC 3, HC B, HC D) for container hydrolytic resistance.
Key technical topics and requirements
- Test conditions: containers filled with specified water, loosely capped and heated at (121 ± 1) °C for (60 ± 1) min.
- Analytical method: measurement of sodium and other alkali/alkaline‑earth oxides in the extract by flame atomic emission or absorption spectrometry.
- Sample preparation: detailed procedures for cleaning, determination of filling volume (different rules for ampoules, syringes, flat‑ or round‑bottomed containers), and sample size.
- Classification: assignment to hydrolytic classes (HC 1, HC 2, HC 3, HC B, HC D) based on measured ion release and container‑specific limit values. Briefly:
- HC 1 - neutral/borosilicate glass with very high hydrolytic resistance (suitable for most preparations including parenterals);
- HC 2 - soda‑lime glass with high resistance due to surface treatment;
- HC 3 - typical soda‑lime‑silica glass with moderate resistance (often for non‑aqueous or less demanding uses).
- Scope limitations: may not be applicable to containers whose internal surfaces have been functionally modified (e.g., silicone‑coated containers ready for direct filling).
- Harmonization: updated to align cleaning and autoclaving procedures with Ph. Eur.; includes containers down to 0.5 ml filling volume.
Practical applications
- Pharmaceutical packaging qualification: verifying primary packaging (vials, ampoules, syringes, cartridges, bottles) for parenteral and other drug products.
- Quality control and lot release: routine testing to ensure glass batches meet hydrolytic resistance requirements.
- Material selection and supplier qualification: comparing glass types (borosilicate vs soda‑lime‑silica) and surface treatments.
- Regulatory support: producing test reports and classification data required by regulators or pharmacopeial monographs.
Who should use ISO 4802-2:2023
- Quality control laboratories in pharmaceutical and medical device companies
- Packaging engineers and material scientists selecting container types
- Regulatory affairs and compliance teams preparing submissions
- Glass manufacturers and contract testing organizations
Related standards
- ISO 4802-1 (titration method for hydrolytic resistance)
- ISO 719, ISO 720 (hydrolytic resistance of glass grains)
- Ph. Eur. and USP <660> (pharmacopoeial context for glass types and classifications)
Using ISO 4802-2:2023 helps ensure reproducible, comparable hydrolytic resistance data for glass containers and supports safe selection and qualification of primary packaging for pharmaceutical use.