Drug delivery
beginning, and you notice that…it’s not a pleasant sensation,” Roe says of an injectable device he uses that delivers just 1ml.
Gas-powered methods may be able to administer drugs with a higher viscosity, but they do have some drawbacks. “As your operating pressures go up, the device has to contain all of those pressures, and plastic can swell, and it can act like a balloon. You don’t want it to explode,” says Roe. There are also limits to how much pressure can be applied for standard needle sizes. Another approach is to use on-body delivery systems. These are usually attached to the skin under clothing and inject the drug slowly over around 15 minutes to an hour. “The volume we can give is much larger,” says Uddin. Devices like this can be used at home, but they aren’t that common, he adds.
Typical autoinjectors are spring-based, but a gas alternative that can drive viscous liquids through with more power could make more drugs available for home use.
Delivery devices
For a delivery device to inject a viscous drug, it needs to generate enough force to push the fluid through a suitably small needle and under the skin within an appropriate amount of time and without causing damage to itself, says Michael Roe, director of device development at pharmaceutical company Kaleo. Achieving that force is the biggest challenge in administering these sorts of drugs, he explains. And to make things even trickier: when you apply force to the fluid, the pressure often causes its viscosity to increase – making it more difficult to push out.
“As your operating pressures go up, the device has to contain all of those pressures, and plastic can swell, and it can act like a balloon. You don’t want it to explode.”
Michael Roe, Kaleo
Gas-powered devices are a possible solution here. Rather than using a spring to apply force, as seen with standard auto-injectors, the pressure is contained within a small gas cylinder. “The cylinder contains all the force, so you’re not putting the plastic under stress until the moment of evacuation,” Roe explains. When you puncture the cylinder, the gas expands into the interior of the device and creates a significant force on the plunger to drive the drug through the needle, he adds. And because pressure is applied more consistently than with a spring, delivery would be more comfortable. With simple spring-powered devices, more force is released initially when the spring is tightly coiled, creating a surge in delivery even at small volumes. “It still has an inrush at the
10
Other technologies use different means to create pressure, for example through a battery-powered pump or by using the gripping motion of the hand to generate force. Ultimately though, they’re all trying to do the same thing: generate enough pressure to get the drug out without breaking. “People have patented everything under the sun and they’ve all got disadvantages,” says Roe. “There are a lot of ways to skin that cat.”
The future of viscous injectables As for the future of drug delivery, viscosity will continue to play an important role in the development of new devices, and Uddin expects to see the mechanisms that push the drug along the needle and into the target site to continue to improve. For players within this space, what patients want – ease of use, with as little pain as possible – will be of central importance, he adds. “Patients are now at the fore of everything that a lot of companies do, because that’s basically the customer, right?” For Roe, what’s most exciting here is the work being done to enable longer injection times, which means that larger volumes can be given. This hugely expands the range of therapies that can be administered at home via hand-held devices. “It can carry a lot more convenience to the user,” he says. “A lot of these things would otherwise be done in an infusion setting or at a hospital.” Over in the lab, digital tools such as machine learning applications could help speed up research by instantly evaluating the suitability of excipients or other solutions, says Gouveia. “It would reduce the time in the lab, and also material consumption.” But for Uddin, the ultimate goal would be to not need injections at all. “The holy grail of biologics is for you to be able to put the drug in a cup and drink it, like you would cough syrup…there’s a lot of work being done in that area,” he says. “Can you imagine that you’d never need to have an injection?” ●
World Pharmaceutical Frontiers /
www.worldpharmaceuticals.net
YAKOBCHUK VIACHESLAV/
www.shutterstock.com
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61
