Needleless injection system is one of the most recent advances done in administration of medication. It is the system through which we can directly administer the drug through the skin without piercing it. It is more efficient, easy to use, economical and less painful even. The drug can be dispersed through the skin in the form of fine mist in which the drug is introduced with the burst of air to cross the skin and enter blood. For e.g. patients requiring growth hormone.
Disadvantages of injectables:
1. Relatively high cost of the needles which results in reduced vaccination
2. Lack of reusability.
3. Painful method of drug administration.
The hypodermic needle was first developed by Alexander Wood in1853 which was used to administer morphine for patients suffering from sleep disorders. But there were certain drawback associated with this route of administration thus needle free injection system was developed later during 1940 and 1950s. Now these devices are gun shaped and used propellant gases to propel or drive fluid drugs into the blood stream. These devices can be modified according to the type and amount of medication with better efficiency.
It is composed of three components:
1. Injection device
2. Disposable needle free syringe and
3. Air cartridge. It is designed as such that it is suitable for self administration and easy to use. The device is made of plastic and syringe is sterilized because it is the part that comes in the direct contact with the skin. The used syringe is then disposed off. Transferable units consist of pressurized metal air cartridges. Instead of pressurized air cartridges some devices utilize spring to generate the pushing force, these devices are also called as air forced system. .Raw Materials
The raw material used should be:
1. Pharmacologically inert and non reactive.
2. Able to tolerate high temperatures.
3. The outer shell of the device is made from polycarbonate which is having good strength and light weight.
4. Fillers are added to make the polymer easier to mould, light weight and durable.
5. Colorants are also used to alter the appearance.
6. Carbon dioxide or helium gas to drive or push the medication into the blood stream.
Some medicines are preferably administered through needleless injection system. For e.g. Insulin, which is given daily to the diabetics, can use needleless system in the form of inhaler, Lidocaine hydrochloride, a local anaesthetics, Fentanyl, an opioid analgesic, and Heparin an anticoagulant can be used as needleless preparations.
It is done under sterile condition and includes:
Making the pieces: The first step is the production of the components of the needleless system from plastic pellets by a process known as injection moulding, all the plastic pellets are put into the injection moulding machine, the material is then passed through the nozzle into the mold which is made up of two halves in which the plastic is under pressure for some time and then allowed to cool when helps in hardening of the plastic. After setting of the plastic it is passed to the conveyors and checked manually for any kind of damage.
Assembling and labelling: The next step is assembling all the parts together and the markings are applied with the help of machines so as to show dosage level, the process is done very precisely and for his purpose machines are specially calibrated.
Packaging: It is done under sterile condition to prevent spread of disease and the device is wrapped with plastic or sterile film and then put in cardboard boxes so that the movement is minimum and damage is also minimum. The boxes also contain instruction manual and safety guidelines for the patient.
Visual inspections are done and then measuring equipment is used to check the dimensions including size and thickness of the device. Labelling and printing is also verified. Since safety considerations forms the important part for drug administration the device should meet the Food and Drug Administration standards and specifications.
Dermo jet is the recently and most widely used needleless injection system formulated by Robbins Instruments.
Dermo-jet "Model G"
This instrument is patented, clinically tested, high velocity and micro jet emitting for needle less administration which is used as local anaesthetic in the dosage of 1/10cc. Volume. Using the Dermo jet involves loading and filling the Dermo jet, making an interdermic papule and then giving the injection. References:
http://www.robbinsinstruments.com/equipment/dermojet/djsub1.html cited on April2010
http://www.answers.com/topic/needle-free-injection-system cited on April2010
http://www.robbinsinstruments.com/equipment/dermojet/injectorheads.html cited on April2010
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