Needle Free Injection Technology
The air-forced needle-free injection systems are typically made up of three components including an:
· Injection device
· Disposable needle free syringe
· Air cartridge
The injection device is made of a durable plastic. It is designed to be easy to hold for self-administration of medicine. The needle-free syringe is also plastic. It is sterilized and is the only piece of the device that must touch the skin. The syringe is made to be disposed after every use. For portable units, pressurized metal air cartridges are included. Less mobile devices have air hook-ups that attach to larger containers of compressed air. Some air-forced systems use a reusable spring to generate the pushing force instead of pressurized air cartridges.
The Manufacturing Process
There are numerous methods of producing each needle-free injection system. The following process focuses on the production of an air-forced system. These systems are made through a step by step procedure which involves molding the pieces, assembling them, and decorating and labeling the final product. The individual pieces are typically produced off-site and assembled by the needle free injection system manufacturer. All of the manufacturing is done under sterile conditions to prevent the spread of disease.
Making the pieces
- The first step requires the production of the component plastic pieces from plastic pellets. This is done by a process called injection molding. Pellets of plastic are put into a large holding bin on an injection molding machine. They are heated to make them flowable.
- The material is then passed through a hydraulically controlled screw. As the screw rotates, the plastic is directed through a nozzle which then injects it into a mold. The mold is made up of two metal halves that form the shape of the part when brought together. When the plastic is in the mold, it is held under pressure for a specified amount of time and then allowed to cool. As it cools, the plastic inside hardens.
- The mold pieces are separated and the plastic part falls out onto a conveyor. The mold then closes again and the process is repeated. After the plastic parts are ejected from the mold, they are manually inspected to ensure that no significantly damaged parts are used.
Assembling and labeling
- The parts are next transported to an assembly line. In this production phase various events occur. Machines apply markings that show dose levels and force measurements. These machines are specially calibrated so each printing is made precisely. Depending on the complexity of the device, human workers or machines may assemble the devices. This involves inserting the various pieces into the main housing and attaching any buttons.
- After the assembly step, the injection devices are put into packaging. They are first wrapped in sterile films and then put into cardboard or plastic boxes. Each part is packaged so movement is minimal to prevent damage. For consumer products, an instruction manual is included along with safety information. These boxes are then stacked on pallets and shipped via truck to distributors.
Quality control checks are done throughout the manufacturing process. Line inspectors check the plastic components to assure they conform to predetermined specifications. Visual inspections are the first test method, but measuring equipment is also used to check the dimensions including size and thickness. Instruments that can be used include laser micrometers, calipers and microscopes. Inspectors also check to make sure the printing and labeling is correct and that all the parts are included in the final packages.
Since these devices can have various safety issues, their production is strictly controlled by the Food and Drug Administration (FDA). Each manufacturer must conform to various production standards and specifications. Announced and unannounced inspections may occur to ensure that these companies are following good manufacturing practices. For this reason detailed records must be kept related to production and design.
NEEDLE FREE DELIVERY OF SOLIDS
As well as the obvious advantages for liquid formulations, such is needle phobia etc. described above, delivering the drug or vaccine in a solid dosage form has the additional advantages that the therapeutic agent will typically be more stable and may not require cold chain storage. In addition, a solid formulation presents the opportunity to combine fast-acting and delayed-release forms such as for vaccines so that the ‘prime’ and ‘boosts’ shots can be given together in a single administration.
NEEDLE FREE DELIVERY OF LIQUIDS
Needle-free injectors have the obvious advantages that they avoid issues relating to needle phobia, needle disposal and the potential for cross contamination of blood-borne diseases. Probably the most well-known needle-free technologies involve liquid jet injection. Liquid jet injector technology was first developed many decades ago and yet it is still not widely used although there are products based on some of these technologies on the market. One of the main attributes of the liquid jet injectors is that these use the drug in a liquid form which therefore does not typically require re-formulation from standard needle and syringe formats. The jet injectors have been developed as both single-use devices and multi-use systems. All require a power source that provides a very high peak pressure behind the liquid in order that it can ‘drill’ a hole in the skin, without the use of a needle, followed by a reduced pressure profile to force the rest of the liquid into the skin. This requires careful control over the power source to ensure accurate and reliable delivery of the drug to different skin locations on the same person. A variety of power sources has been developed for these liquid jet injectors, including:
· Compressed gas
· Controlled chemical reactions
Needle Free Injectors
The Biojector 2000(Figure 4) is a durable, professional-grade injection system designed for healthcare providers. The Biojector 2000 is the only needle-free system in the world cleared by the FDA to deliver intramuscular injections. The system can also deliver subcutaneous injections, and is being used for intradermal injections in clinical trials.
The Biojector 2000 uses sterile, single-use syringes for individual injections, which prevent the cross-contamination that has been reported with fixed-nozzle jet injection systems.
More than 10 million injections have been administered successfully using the Biojector 2000, with no reports of major complications. Because there is no needle, the Biojector provides healthcare workers with an unparalleled level of protection against accidental needle stick injuries. In high-risk situations, such as delivering injections to patients known to be infected with HIV or hepatitis, the Biojector is an ideal injection system.
The Vitajet 3(Figure 5) is an easy-to-use, economical needle-free injection system for delivering insulin. The system requires no maintenance or re-assembly. With disposable nozzles that are replaced once-a-week, the Vitajet 3 offers the quality of a reusable medical product, with the convenience and safety of a sterile disposable. The exclusive, easy-to-read Crystal Check disposable transparent nozzle allows inspecting the dosage prior to injection and visually confirming loading and full discharge of your insulin after each use.
The Vitajet 3 received the FDA marketing clearance for delivering subcutaneous injections of insulin in 1996. Since then, the system has been used to deliver hundreds of thousands of injections, safely, economically, and without the use of a needle.
Bioject developed the cool.click (Figure 6) needle-free injection system for delivering Saizen recombinant human growth hormone. In some children, naturally occurring growth hormone is absent or is produced in inadequate amounts. In these cases, Saizen or growth hormone replacement must be injected to maintain normal growth.
Cool.click is a customized version of Bioject’s Vitajet 3 needle-free injection system. The system includes customized dosage features to accurately deliver variable doses of Saizen and was designed with bright colors to make the injector attractive and non-threatening to children. The cool.click received FDA market clearance for delivering subcutaneous injections of Saizen in June, 2000.
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