Nest 510k injection pens are ideal for any medication that can be delivered in relatively small volumes e.g. 0.8mL per dose or less. This makes them well suited for medications like semaglutide, tirzepatide, liraglutide, testosterone, insulin etc. where the dosage is in the milligram range. However you are asking yourself, how do I choose a pen suitable for my medication? Here are a few factors to consider:
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The maximum dosage of the pen. To be clear every pen holds a 3mL cartridge that holds 300 units. The minimum increment of most of the pen models is .01mL/unit per click which means 3mL/.01mL = 300. This is how much liquid the pen holds. The maximum dosage is how many units/.01mL can be delivered in a single shot. For example an 80 unit pen will will allow the user to twist the volume selector knob all the way out 80 clicks/80 units/0.8mL to deliver a single shot of that amount. Again to emphasize, this dosage of 80 units is only 80 out of the 300 contained in the pen.
- The minimum delivered dose is how much volume in mL is delivered per click (partial turn) of the dosage selector wheel. A click is usually .01mL but may be other units as well. Nest also produces a .0075mL and .0028mL per click model.
- The dosage units are also important when considering a pen model. Most models are in units “U” which refers to insulin units which are .01mL. After all these injection pens are modeled on ISO 11608 which are guidelines for producing insulin injection pens. However some models exist for certain known drug concentrations. For these pens instead of showing units, they show milligrams or international units “IU”. An example would be a pen designed specifically for semaglutide like TD75112. This pen is for a semaglutide concentration of 4mg/3mL. The math on that means 1.34mg/1mL or if you multiply by .01mL/per click to get mg/click you find .0134mg/click. That means at 19 clicks (19*.0133) the pen would deliver 0.25mg. Instead of showing 19 on the dosage display the pen simply shows 0.25mg. When a pen has this type of display it will be clearly described in the product description and title.
- Pens are available for long or short stopper cartridges. The 3mL cartridges the pens use have a rubber stopper in them that can be 11.3mm or 8.2mm long. This seems like a small detail but is key to the pen delivering the correct dose. If you aren’t sure, ask us or your pharmaceutical packaging supplier for help.
- Reusable or disposable. Reusable injection pens are just that, reusable. They can be easily unscrewed by hand so a new 3mL cartridge can be installed. They are rated to 3000 uses. Disposable pens are sealed and cannot be disassembled once they are put together. Technically speaking the FDA refers to them as a drug/device combination device. They require an additional filing beyond the 510k, which we are happy to help you navigate. The assembly is easy, simply snap the two pieces together by hand. Anyone can assemble 6-7 pens per minute. Automation for assembly is also available, ask us for help if you need it
- Long cap or short cap models. Long cap models have a longer cap that allows the patient to put the cap on while the pen needle is still installed. Short cap models force the patient to take the pen needle off after use. Theoretically this encourages them to use a fresh pen needle each time they use the pen.
- Packaging. The pens are available in trays for automatic assembly, in paper boxes and also some models with reusable carrying cases that hold 3 or 4 double sided pen needles.
- Big window, small window or no window. The big window pens have a large window on the dosage display. The small window models have a smaller window that only shows the current number displayed but makes the numbers slightly harder to read. The no window model has no volume selector, the operator goes by clicks only.
- All models by default are meant to work with ISO 11608-3 style 3mL cartridges. However adaptors are available to allow the pens to be used with 1.5mL cartridges. Two different types of adaptors are available as the 1.5mL cartridges can either be half as tall or half the diameter of the 3mL cartridges. If you need adaptors please let us know.
Hopefully this guide to choosing an injection pen was helpful. If you have any additional questions please don’t hesitate to ask!
