A PROCESS that yields drug particles as fine as smoke could relieve a critical shortage of insulin in developing nations. The technique could also enhance the effectiveness of other drugs, as well as allowing them to be delivered in easier ways, such as through skin patches.
A team at Deakin University near Melbourne has shown that people with diabetes may only need a third as much insulin when it comes in the new form. This consists of tiny particles under 100 nanometres across. In tests on rats, 0.15 units per kilogram of body weight produced the same response as 0.5 units of normal insulin.
鈥淏ut the study didn鈥檛 set out to establish a minimum dose, so it may be more than three times as potent,鈥� says Paul Zimmet, director of the International Diabetes Institute at Monash University.
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The new form also produced a more sustained effect. The effects of a normal insulin injection start to fade after about 30 minutes, but the nanomised insulin continued to act strongly for 60 minutes, and the benefit could be even longer. That means diabetics might be able to cut back from five injections a day to only two or three.
The particles were produced by Eiffel Technologies of Melbourne, using a 鈥渟upercritical fluid鈥� process developed by Neil Foster鈥檚 team at the University of New South Wales. Other companies are also developing this technology.
If it lives up to its promise, nanomised insulin could help relieve a worldwide shortage of insulin that is causing the death of millions of diabetics in developing nations, Zimmet says. 鈥淚f Eiffel鈥檚 technology is more efficient, it鈥檚 very important.鈥�
To nanomise insulin, a gas is first put under such high pressure that becomes 鈥渟upercritical鈥� and behaves like a liquid. Normal insulin is dissolved in the supercritical fluid, which is then suddenly decompressed, making the insulin precipitate out as tiny particles.
Conventional milling or grinding processes cannot produce particles smaller than between 1 and 2 micrometres. The supercritical fluid technology consistently produces particle sizes of between 50 and 100 nanometres or smaller, Foster says.
It is not clear why nanomised insulin is more efficient or why it lasts longer. But Zimmet, who reviewed the Deakin study for Eiffel, points out that insulin molecules normally cluster together in a 鈥渟ix-pack鈥� configuration, which the body has to convert to the single, or monomer, form. The smaller particles may deliver insulin in the accessible monomer form.
Nearly half of all drugs are currently provided in a form that isn鈥檛 easily available to the body, says Eiffel head Christine Cussen. She thinks the nanomising process might greatly improve the availability of other drugs, too.
And because the particles are so tiny, it might even be possible to do away with injections altogether and deliver drugs such as insulin through skin patches, or nasal or oral inhalers.