Interview with Steve Duckworth: Colours and Additives for Cyclic Olefins

The overlap in technologies across traditional medical instruments and drug delivery devices is gaining prominence. Healthcare providers are on the look out for more innovative mechanisms from drug companies to allow as many patients as possible to treat themselves from home, thereby saving hospital expenditure. Being inert, durable, low cost, lightweight and colourable, plastic is the material of choice for designers of these mechanisms, particularly as new biotech drug formulations enter the realm. Ahead of next year’s Pharmapack show in Paris on February 13-14, Medical Plastics News interviewed Steve Duckworth, head of medical and pharmaceutical at Clariant’s Masterbatch unit.

Sam Anson: Looking at the name Pharmapack in a literal sense, readers might be forgiven for thinking that the exhibition is only for traditional packaging products like drug blister packs, fluid bags and disposable films. But they’d be wrong wouldn’t they?

Steve Duckworth: Absolutely. The show is more important than they might initially realise. Despite the name, approximately half of the people there are involved in drug delivery devices. And it’s really worth visiting. Being in Paris, the show attracts people from all over Europe. And it’s a really nice format too.

Sam Anson: You’re not the first person to recommend it. What can visitors expect to see there from Clariant?

Steve Duckworth: Clariant will have two stands. A team from Performance Packaging, part of the Functional Materials business unit—formed following Clariant’s acquisition of Süd Chemie in 2011—will be there to talk about desiccant and barrier packaging solutions used in both primary packaging of pharmaceuticals and secondary packaging products for drug delivery devices, which help protect sensitive products from oxygen and water degradation.

Sam Anson: And what about Clariant’s Masterbatch unit?

Steve Duckworth: On our stand, number 333, we will be focusing on our recently introduced range of Mevopur USP/ISO compliant additives aimed at improving the final product or the productivity.

Sam Anson: I heard that you are working closely with Topas and their cyclic olefins. Can you tell me a little more about this?

Steve Duckworth: Topas cyclic olefin copolymer is a very interesting material from a number of stand points but particularly its clarity combined with rigidity. It is clear like glass. This makes it ideal for the replacement of glass in syringes or ampoules.

Sam Anson: I was told that syringe and ampoule manufacturers have the biggest appetite for cyclic olefins. What is driving this?

Steve Duckworth: Demand is being fuelled by three factors. First, there are safety concerns related to breakages of glass-based syringes during transportation. The Topas olefins are shatterproof so there’s more durability there. Second, the fact that plastic syringes and ampoules can be injection or blow moulded gives opportunities for reduced costs while maintaining high clarity. Third, injection moulding also gives options for designers to begin to think about newer and more intricate shapes.

Sam Anson: According to a report published by USA-based consultancy firm Greystone Research Associates in April 2012, demand for prefilled syringes is expected to grow at double digit rates to 4.75 bn units in 2016. The report says that cyclic olefins are a “material to watch”. How is Clariant helping to supply this demand?

Steve Duckworth: Working with Topas, we have developed a number of standard colorants and additives for cyclic olefins. Two to note are our UV filters in amber and pink and our additive which can prevent yellowing following up to two rounds of gamma sterilisation. Both technologies have been developed from tried and trusted technologies.

Sam Anson: Tell me about the UV filtering first.

Steve Duckworth: Some contents of prefilled syringes and ampoules, particularly new ‘biologic’ products can be highly sensitive to light and thus need to be protected using a colorant which filters out UV light. Clariant already manufactures a range of USP grade amber and pink colorants for polyolefin-based ampoules and syringes. We have worked with Topas and have developed USP/ISO pre-tested pink, amber and other colours which can be used with cyclic olefins to filter out different parts of UV light, depending on the customer’s requirement.

Sam Anson: And the yellowing preventing additives?

Steve Duckworth: Some polymers, and particularly polypropylenes and cyclic olefins, undergo a yellowing effect under gamma or e-beam sterilisation. Clariant offers a USP/ISO grade additive that counteracts this yellowing effect to maintain colour and clarity.

Sam Anson: You mentioned that repeat sterilisation is a particular problem. Tell me more.

Steve Duckworth: We know that there is a demand from manufacturers to offer products which can be repeat sterilised, as end users wish to have the option to re-sterilise devices. In addition, even with a single sterilisation, if problems are encountered during the process, the sterilisation may be repeated. As part of a radiation study, we sterilised three grades of Topas material at 0, 25, and 50 kGy to determine the amount of additive required to reduce the colour shift. As a result we can now offer a Mevopur additive for protection of up to two cycles of gamma or e-beam sterilisation of devices made from cyclic olefins.

Note: Topas cyclic olefins are usually used for one sterilisation cycle but should a manufacturer need to repeat a gamma cycle due to a line malfunction for example they can do so without issue from Clariant’s gamma testing. That said, Topas do not recommend repeat sterilisation in general.

Sam Anson: Fascinating. That’s advanced thinking. As a leading supplier of colours for plastics, you must have a privileged view of how things are changing in this area for USP/ISO materials.

Steve Duckworth: I do. And things are changing quickly. Just over a year ago I said to Medical Plastics News that I thought colours are coming. And that trend is certainly showing no signs of abating. For example colour coding has become a key aspect to device design, particularly in drug delivery. For example a new generation of insulin treatment offers patients the opportunity to only require a single daily injection, replacing insulin which required three or more doses a day. The insulin is typically self-administered by a convenient pen device However, manufacturers are concerned that despite labelling, patients may mix up these devices and mistakenly give themselves an insulin overdose by injecting the single dose more than once in a day. Their solution to this is to use bright colours to safely differentiate between the two pens to minimise the risk of a mix up.

Sam Anson: What additives are you offering which help plastic processing?

Steve Duckworth: A popular product range is our USP/ISO laser additives for marking and welding that comes with USP Class VI compliance. Of particular interest is the welding additive. It allows clever things to be done with the design, offers more reliability than adhesives and eliminates the potential problem of residues. Also as part of this range we offer UPS/ISO nucleants to help reduce cycle time, optimise wall sections and solve production problems.