Critical choice

The latest innovations in glass and plastics are expanding the choice of primary packaging for pharmaceuticals

Although it is one of the oldest pharmaceutical packaging materials, demand for glass containers continues to grow, thanks to technical advances such as lightweighting and innovative surface treatments. The development of biotechnological drugs with lower concentrations of very sensitive active ingredients has placed new demands on glass as even the slightest traces of metal ions can adversely affect the shelf life and effectiveness of modern formulations.

To meet these demanding applications, Schott forma vitrum has developed a coating technology that deposits a layer of silicon oxide (SiO₂) on the internal surface of the container. Schott Type I Plus uses Plasma Impulse Chemical Vapour Deposition technology to create an ultra-thin, transparent layer that is covalently bonded to the glass and is therefore very stable. It acts as a diffusion barrier and greatly reduces the risk of product degradation and chemical interactions between drug and container, the company says.

SiO₂ coated containers take over where conventional pharmaceutical glass reaches its limits – e.g. for packaging high value radioactive diagnostics, low concentrated proteins, pH-sensitive products and formulations with complexing agents such as EDTA and citrates. At the same time they are compatible with existing processes, including washing, sterilisation and depyrogenation, as well as conventional filling line equipment.

One area where glass is continuing to make an impact is syringes. Schott's forma 3s is a completely sterile syringe set, delivered with or without needle, ready for filling. The barrel is made from Schott Fiolax, a highly resistant borosilicate glass, and is said to offer tight tolerances in diameter and thickness.

German company Gerresheimer Glas's subsidiary Buender Glas has developed RTF, a disposable injection system supplied sterilised, largely assembled and ready to fill. To meet the rapid growth in demand for sterile, ready-to-fill syringes, Gerresheimer recently built a large-scale production plant for Buender, including clean rooms that comply with pharmaceutical standards.

reduced handling

The main advantage for the pharmaceutical industry of ready-to-fill syringes is that they greatly reduce the amount of handling required. Washing, siliconisation and drying of the glass body, sterilisation of the needle, assembly of the needle protection device and ETO sterilisation all take place prior to delivery.

Gerresheimer recently reinforced its position in the international pharma glass market through the acquisition of Mexican company Ampolletas and its marketing company Kimble Enbosa. With sales of €35m (US$32m), Ampolletas is the largest manufacturer and supplier of tube glass packaging for pharmaceuticals in Central America, producing vials, ampoules, syringes and lab glassware.

But glass is not the only answer to modern pharmaceutical packaging needs. Schott Pharmaceutical Packaging has developed TopPac, said to feature high chemical resistance, glass-like transparency, good barrier properties, resistance to ionising radiation, resistance to breakage, thermal stability and excellent workability. Made from Topas, a pure polyolefin cycloolefin polymer (COP), the products are inert and light weight, show no ion or heavy metal release, are easily emptied due to the hydrophobic surface.

TopPac containers are suitable for oncological preparations, biotechnical products, solvents, products with extreme pH-values, toxic products, products sensitive to metal ions, blood products and proteins. Furthermore, they offer the advantages of flexible container design, such as integrated luer lock, minimised dead volume, low dimensional tolerances and pyrogen-free processing.

However, it is when glass and plastics are used in combination that some of the most beneficial innovations come about. Buender's latest development in syringe technology is Safetyject, a complementary plastic-based system that fits all ready-to-fill syringes with a pre-mounted needle. The syringe is placed in a transparent plastic barrel with a two-part plunger rod. On completion of the injection, pressure is briefly reapplied to the plunger head, which causes the system to slip the sturdy barrel over the syringe, completely covering the needle and preventing reuse of the syringe.

Greater security is also one of the benefits for patients provided by Schott's new translucent aerosol container for delivering medication into the respiratory system. Schott PURGARD is a double shell container made of pharmaceutical type I glass with an outer polypropylene jacket.

patient protection

The glass inlet design has been computer-optimised and is sheathed in a 1mm outer thermoplastic layer, enabling the device to withstand internal pressure of up to 40 bar. Safety vents in the polymer shell ensure a controlled reduction in pressure if the glass inlet is damaged, while the polymer jacket holds together the glass inlet and the valve even if the container is subjected to extreme force.

As the external dimensions are the same as those of conventional aluminium containers, Schott PURGARD is compatible with standard valves, filling lines and application systems. And as the outer container is translucent, users can tell at a glance how much product is left.