Barrier effect of primary pharmaceutical packaging: medicinal product protection and environmental benefits

Primary pharmaceutical packaging plays a key role in the protection of medicines, which may be damaged by external factors during storage and distribution. To avoid these problems, materials with barrier properties against oxygen, light and moisture have been developed, which are essential for isolating the medicinal product while maintaining its stability and safety. High-performance packaging materials not only protect products, but also offer numerous environmental advantages.

Oxygen barrier effect

Oxygen is one of the main enemies of drug stability. Oxidation can degrade the active ingredients, reducing the drug’s effectiveness and, in some cases, even generating dangerous compounds. Depending on the specific drug formulation’s oxygen sensitivity, several factors must be considered when choosing the packaging:

• The material: glass packaging presents a total barrier against oxygen, while plastic offers varying degrees of protection, depending on the oxygen transmission rate (OTR) of the specific material. To increase the barrier of HDPE, for example, special additives are available that guarantee a 30% higher performance.
• The closure system: to improve barrier properties, we recommend using suitable closure systems and, in specific cases, adding heat-sealed liners to the bottle mouth.
• The degree of chemical-physical interaction: under specific conditions, the chemical-physical interaction between the container and the drug formulation may generate certain impurities, classified as Extractables and Leachables.  These substances can be potentially harmful and compromise the safety of the pharmaceutical product and, therefore, the health of the patients taking it.  In this sense, there is a broad regulatory framework for E&L (Extractables and Leachables) evaluation, which includes, most importantly, the United States Pharmacopoeia (USP), the European Pharmacopoeia (EP) and FDA regulatory guidelines. USPs <1663> and <1664>, for example, include some descriptive best practices on how to assess the E&L associated with pharmaceutical packaging.

Light barrier effect

Light can speed up the degradation of sensitive drugs. In particular, UV radiation can cause several chemical reactions, including oxidation, racemisation and isomerisation. These three reactions influence the structure of the formulation, although in different ways, and thus affecting the effectiveness of the therapy.

Primary packaging with light barrier properties, such as amber-coloured glass or plastics, prevent light from penetrating and damaging the medicine. This protection is crucial for drugs such as vitamins and some antibiotics, which are especially sensitive to light exposure.

Moisture barrier effect

Moisture can have negative effects on medicinal products, in particular it can be the cause of:

• Alterations to the chemical structure through oxidation, hydrolysis and reduction processes.
• Physical changes due to polymorphism, precipitation, loss of volatile compounds, separation or liquefaction.
• Microbial growth due to the establishment of favourable environmental conditions for the growth of bacteria.

Materials with high moisture resistance, such as glass or plastics with barrier properties (such as PP or HDPE) are essential to keep the drugs dry and stable. Special additives compatible with polyolefins are also available to improve the active and passive moisture barrier. These are layers of active material applied to the inside of the container that keep the moisture content close to 0%, preventing degradation of the medicine.

It is also possible to insert desiccant layers inside the capsules to further improve protection against moisture and ensure that the product retains its effectiveness throughout its shelf life.

Benefits for the protection of medicines

The barrier properties of primary pharmaceutical packaging offer several advantages:

• Chemical stability: by protecting the drugs from oxygen, light and moisture, primary packaging ensures that the active ingredients remain stable and effective.
• Patient safety: a drug that maintains its chemical integrity is safer for patients, as there is less risk of side effects due to degradation.
• Extension of shelf life: by improving the drug's resistance to external agents, barrier packaging can extend the product’s shelf life.

Environmental benefits

In addition to protecting medicines, primary pharmaceutical packaging with barrier properties can have a positive impact on the environment. The use of advanced materials and innovative technologies can reduce the amount of barrier material required for packaging, thereby reducing the amount of material that is subsequently discarded. Reducing the amount of both primary and secondary packaging also leads to optimisation during transport and a lower fuel requirement, further reducing CO2 emissions.

In addition, more resistant materials can improve efficiency in the distribution chain, reducing the risk of spoilage and thus the waste of medicines.

Conclusion

The barrier properties of primary pharmaceutical packaging are essential for the protection of medicines against external factors such as oxygen, light and moisture. These materials ensure drug stability and efficacy, contributing to patient safety and extending the shelf life of products. Furthermore, the use of advanced packaging can offer significant environmental benefits, making the pharmaceutical industry more sustainable.

Given the high technical complexity of the material, a close collaboration with the packaging supplier is essential in order to be advised on the most suitable packaging material according to the chemical characteristics of the formulation.