China’s Pharmaceutical Glass Packaging Standards: 24 Standards, Aging Rules and Testing Priorities

Standards are the backbone of any packaging sector. As pharmaceutical packaging evolves, industry standards must keep pace. Recent changes in medication demand have pushed pharmaceutical packaging rules forward, and medicinal glass standards are a case in point.

China now has 24 pharmaceutical glass standards: 19 national and 5 industry standards. By type, there are 9 product standards and 15 test-method and related standards. A major issue is that many are old—most date from the 1980s or 1990s—and no longer reflect current industry or product development. Adoption levels are also weak, with non-equivalent adoption common. Since WTO accession, the pharmaceutical glass sector and its products must align with international practice, making standards reform a first step.

Take the 9 product standards. Market shifts have fundamentally changed the structure and functions of pharmaceutical glass bottles, leaving some old standards unsuitable as certain formats decline. Large-size and wide-mouth bottles for tablets, for instance, have largely given way to plastic bottles and aluminum foil. Today's market is dominated by oral liquid preparations for health-care and nutritional drugs, moving toward serialized, smaller formats. Threaded tubular glass bottles, mainly used for tablets and powders, are also losing volume to plastic bottles, aluminum foil and other materials.

The 'Pharmaceutical Glass Bottles' standard is a clear example of an aging product standard that no longer fits market demand or current products. The National Medical Products Administration has placed it on a restriction and revision plan. To meet the needs of the pharmaceutical industry, biomedicine and biological preparations, the not-yet-officially-published 2000 edition pharmaceutical industry standard will refer to related standards.

Testing pharmaceutical glass

By product use, pharmaceutical glass testing falls into three main groups: physicochemical performance, specifications and dimensions, and appearance quality. Once aligned with international pharmaceutical glass standards and test methods, testing will also need to cover glass chemical composition and leachable harmful substances.

Physicochemical performance is a key quality indicator and a reflection of a product's internal quality, directly affecting drug quality. Test items include water resistance, internal stress, internal pressure resistance, thermal shock resistance, freeze resistance, breaking force, acid resistance and other durability properties.

Water resistance means the chemical stability of pharmaceutical glass. Because glass containers contact drugs directly, they must not cause drugs to deteriorate or fail through chemical changes during shelf life. Chemical stability therefore directly affects drug quality.

Water resistance testing uses the grain method and the container method. In principle, a measured amount of acid solution is used to neutralize relevant substances on or within the glass container. The grain method evaluates the chemical performance of the glass material, following GB12416.2-1990, Glass grains—Test and classification of water resistance at 121°C, and GB/T6582, Glass—Grain test and classification of water resistance at 98°C. The container method evaluates the inner surface, following GB12416.1-1990, Pharmaceutical glass containers—Test method and classification of water resistance, and GB/T4548-1995, Glass containers—Test method and classification of inner surface water attack resistance.

In addition, to align with standards, China has drafted a national standard: Glass products and glass containers—Determination and classification of water attack resistance by flame spectrometry. This standard can quantitatively measure substances released by glass surfaces under water attack and the amount released.

Internal stress reflects annealing quality or annealing characteristics. Poorly annealed glass containers are more likely to break or shatter during use, affecting drug filling and medication safety. The usual standard is GB12415-1990, Pharmaceutical glass containers—Inspection method for internal stress. Its principle uses optical path differences at different wavelengths to determine internal stress; a common instrument is the LRR-8 digital quantitative stress meter.

Internal pressure resistance measures the overall strength of a glass container. Internal glass structure, uneven wall thickness and surface defects all affect strength. The test method standard is GB/T4546-1998, Glass bottles and jars—Test method for internal pressure resistance. A common instrument is the TYJ-B linear pressure-increasing internal pressure tester.

Thermal shock resistance tests a glass container's ability to withstand temperature change, usually expressed as a heat-resistant temperature difference. The method standard is GB4547-1991, Glass containers—Test method for thermal shock resistance and thermal shock endurance. A common instrument is a digital automatic temperature-controlled thermal shock tester.

Freeze resistance measures low-temperature performance and is mainly used for lyophilized drug glass vials. The test equipment is a freezer operating below -43°C.

Breaking force tests the easy-break performance of ampoules and is an important indicator of ampoule usability. A common instrument is the ZLY-2000 digital breaking force meter.

Acid resistance and related chemical attack resistance measure glass chemical stability. Test methods include GB6582-1986, Glass—Determination of hydrochloric acid resistance at 100°C by flame emission or atomic absorption spectrometry; GB/T15728-1995, Glass—Gravimetric test method and classification for resistance to boiling hydrochloric acid; and GB/T6580-1997, Glass—Test method and classification for resistance to mixed aqueous solutions. Main instruments include flame photometers, atomic absorption spectrometers and routine laboratory equipment.

Specifications and dimensions reflect key forming quality. Consistent, stable dimensions are the foundation of pharmaceutical packaging production and strongly affect filling, sealing, storage and use.

For geometric dimensions, bottle mouth and body dimensions are generally checked with digital electronic calipers, vernier calipers or height gauges.

For wall, bottom and mouth thickness, common instruments include digital electronic bottom and wall thickness gauges and digital electronic mouth-edge thickness gauges.

Vertical axis deviation checks bottle verticality. The method standard is GB8452-1987, Glass containers—Test method for vertical axis deviation of glass bottles. The measuring instrument is the ZPY-10 digital axis deviation gauge.

Straightness checks the degree of bending in glass tubes. A common instrument is the LSR-1000 digital glass tube straightness meter.

Weight and capacity are measured by weighing and titration to determine bottle weight and volume.

Appearance quality covers surface defects in glass containers, mainly stones, bubbles, striae, bubble lines, cracks and seams. These items are generally inspected visually or with a graduated magnifier.

Chemical composition and harmful substance content

Testing chemical composition and harmful substance content is important for raising pharmaceutical glass container quality and aligning with international levels. The forthcoming pharmaceutical industry standard, Classification of Pharmaceutical Glass Composition and Its Test Methods, is a non-equivalent adoption of ISO 12775-1997, Glass—Classification by composition and test methods for normal large-scale production. It clearly classifies and specifies composition, material requirements, performance and application scope for various pharmaceutical glasses.

Raw materials for pharmaceutical glass often introduce As2O3 and Sb2O3 as refining agents. Standards set limits for their release. China is currently drafting related control and testing standards to limit harmful elements from a safety and hygiene perspective.

This article was reprinted from China Packaging Network (pack.cn); original link: http://news.pack.cn/show-361851.html.