Abstract: A gas powered, durable, needle less jet injection device includes a hand held injector who provides a volume of liquid or quantity of powder medication to be injected, an injection orifice and an injection piston. Forceful movement of the injection piston causes an injection jet of medication to be expelled from the injection orifice. The injection device also includes a hermetically sealed gas pressure cartridge which is opened in the preparation to effect a jet injection and which powers the jet injection but from which pressurized gas is not allowed to flow in volume until a user of the device shifts a valving spool.
Now days, these are also known as jet injection, painless injection. Needle free injection is the device held against the skin at the injection site and when activated, the injector propels a fine stream of drug in to the skin. The most common orifice size is 0.127 mm, compared to a 25-gauze needle, which is about 1 mm in diameter. This smaller diameter of orifice creates an ultra fine stream of high-pressure fluid that penetrates the skin with out using a needle. Metal spring or compressing air Co2, N2 and helium gases create the propelling force.
The concept of needle free injection eliminates wide spread fear of injection related to pain among patients, at the same time eliminates the risk of the transmitting infections like Hepatitis and HIV by needle. About 1 million needle injuries are recorded every year associated with considerable expenditure for treating infected persons.
There are a variety of problems associated with the hypodermic needles used for injections especially for vaccine. One of the most significant drawbacks is the relatively high cost of the needles. The cost results in a lower vaccination rate; especially for children in developing countries. Another problem with traditional needles is the lack of reusability, if a needle syringe is not sterilized, reusing it can lead to the spread of disease. Additionally many people have a fear of taking injection dosage form because of needle associated with it. These drawbacks have led to the development of alternative delivery systems to needle injections. Needle free systems are designed to solve these problems making them safer, less expensive and more convenient. It is anticipated that these systems will increase the incidence of vaccination and reduce the amount of prescribed antibiotics.