Pen-type syringes are referred to as injection pens. They are named for their pen-shaped appearance. Their main function is to provide external injection power for drug refills. Compared with traditional glass syringes, they are safer, more convenient, and more precise in controlling dosage. The drug is stored in the refill and is generally used with a specific injection pen. The refills of different manufacturers are not compatible. When using, remove the pen cap, install the injection needle to exhaust air, adjust the required dose and drive the injection button to achieve and complete drug delivery.
In 1853, Scottish doctor Alexander Wood invented the medical hypodermic syringe and was hailed as the father of modern syringes; in 1925, Novo Nordisk launched the first insulin syringe; in 1978, Dr. Reith of Southern General Hospital and others designed the prototype of the modern insulin pen, which was produced by Hypoguard in 1981 and named “Penject”, the world’s first commercially available insulin pen.
The injection pen has core advantages such as precise quantitative injection, self-medication, safe and convenient use, etc. It accurately meets the needs of patients with diabetes, weight loss and other long-term medications, and has gradually become a mainstream injection solution. At present, the injection pen is mainly used for subcutaneous injection of various biological drugs, such as recombinant human growth hormone (drugs for dwarfism), insulin and analogs (drugs for diabetes), GLP-1 drugs (drugs for diabetes), teriparatide (osteoporosis drugs), recombinant human follicle-stimulating hormone (drugs for infertility), apomorphine (drugs for Parkinson’s disease) and other chronic disease drugs that require medium- and long-term self-medication, as well as high-priced targeted drugs such as adalimumab and alirocumab, and consumer markets such as high-end beauty needles.
The mainstream GLP-1 medicine injector on the market, including Wegovy for liraglutide, dulaglutide, telpotide, and semaglutide, are all disposable PFS injection pens, while Novo’s semaglutide Ozempic is a disposable multiple-injection cartridge pen, commonly known as the Novo pen. Mainstream GLP-1 drugs basically use disposable multiple-injection pens and disposable single-injection pens. It is worth noting that Wegovy and Mounjaro use different injection pen specifications in Europe and the United States, but Novo and Eli Lilly have basically similar strategies, using disposable single-injection pens in the United States and disposable multiple-injection pens in Europe, and both are modified fixed-dose multiple-injection pens, and each pen can inject 4 times of the same dose of GLP-1 drugs.
Comparison of four GLP-1 injection pens from Novo Nodisk and Eli Lilly
The structure of the adjustable dose multiple automatic injector includes a pen cap, a disposable needle, a non-detachable cartridge drug refill, and a mechanical power device for the injection pen. The mechanical power device of the injector adjusts the dose by rotating the torsion spring and stores energy at the same time. By pressing the injection push button, the required dose is automatically injected, and then the dose is automatically reset to zero after the injection. This outward injection process is achieved through fork shaft transmission, similar to the principle of screws and nuts. Because it is a multiple injection, it is necessary to remove the pen cap to replace and load the disposable needle. Currently, Novo Nordisk’s insulin automatic injector flextouch series and semaglutide automatic injector, most other manufacturers are adjustable dose multiple injection manual pens.
The structure of the fixed-dose single automatic injector includes the pen housing, internal mechanical transmission design components (including pre-compression springs and push rods, etc.), drugs pen cores and pre-installed needles. Because it is a single-injection design, the injection needle is pre-fixed and does not need to be replaced. After the active component at the needle end of the injection pen squeezes the skin, the internal structure of the injection pen is triggered, the pre-compression spring is released, and the push rod is automatically pushed to complete the injection. After the injection, the needle automatically retracts for protection to prevent the risk of needle sticks. Currently, Eli Lilly Zepbound injection pen for Tirzepatide, Ypsomed’s YpsoMate autoinjector, and SHL’s Molly autoinjector are all based on this design.
Healthy Tree Medical has an integrated industrial chain of design, R&D, production and sales, and has the ability to independently develop injection pen production, assembly and testing equipment, including fully automatic power component lines, fully automatic assembly lines, semi-automatic assembly lines, injection pen testing machines, light inspection machines, nasal spray pressing devices, twist rod labeling machines, etc. The company can provide customized equipment and injection pens according to customer needs. Healthy Tree Medical adheres to the technical concept of “letting professionals do professional things” and is committed to providing pharmaceutical companies with self-administration devices and corresponding injection solutions.