If one is working with medication formulas that are to be injected, it is always best to work with such items in as sterile conditions as possible, even if the properties tend to be anti-microbial. The above photo is of a typical lab glovebox which can cost many thousands of dollars. The atmospheric air is full of contaminants, many of which are microbial. I would like to suggest on this page how one can save money by constructing a do-it-yourself glove box, sterile clean box, isolation chamber, etc. Of course, one will never achieve 100% sterility, but one can limit the chances of contamination by using this box and I would employ it routinely when formulating various injectables that I describe on this website. I would also like to note that all of my injectable formulas are innately anti-microbial and will generally kill most microbial contaminates on contact which is always a good thing for DIY'ers. However, life being as it is, why take chances? Always strive to work in as clean aseptic conditions as possible! This glovebox will mostly be designed for still air, though one could easily have it rigged for positive air pressure. I have added 0.2 micron filter membranes to this configuration to filter out bacteria and fungal components which I will discuss at length later.
Parts List:
1) A clear plastic large box container system,
2) Veterinary OB shoulder length gloves or similar gloves,
3) Two PVC pipe fittings or as I did, take one large 4" PVC coupling, saw in half and machine lips,
4) steel screw band to attach gloves to PVC fitting,
5) a crystal clear plastic panel (optional) sealed with silicone, attached with pop rivets & washers
9) adhesive seal stripping for lid and container lip to make it air tight.
My DIY glovebox is made from a clear plastic Sterilite 27 Gallon Stacker Box that I purchased at Walmart. It is 25.75" x 18.38" x 19.38" with a price around US$15.00 and pictured below. I will invert it with the top lid being the bottom floor on which to work. I will cut two arm-holes into the front, insert PCV pipe fittings, and attach thin plastic shoulder length veterinary OB gloves to allow hand insertion into the box. I will also add a plastic clear panel to more easily view the insides though this may not be absolutely necessary since the plastic is pretty clear already. I will also add legs and an easily sterilized Plexiglass sheet to the floor of the lid along with a 0.2 micron MCE filtration system and gas fittings. I already own a medical grade ozone generator which operates on USP Oxygen. I will pipe ozone gas into this chamber through the 0.2 micron filters which should nicely sterilize the internal contents. Again, this is not absolutely necessary as one could probably simply spray an anti-microbial spray inside (like 6% hydrogen peroxide), seal and wait a reasonable time for a safe working environment. As I said, I already own a ozone generator, so I will go the extra step.
Filtration System
My DIY glovebox is unique because of the filtration system. Most gloveboxes use expensive HEPA air filters which are out of reach of most of us. One needs to have at least a 0.2 micron rated filter in order to filter out most common bacteria, fungal and other microbial life forms. It is way too expensive to get that pore size in HEPA filters. I have found the best way to get a 0.2 micron rating is simply use small 47mm filter membranes as used in labs for various small scale filtration processes. One can often find them on eBay for pennies on the dollar if you are patient enough along with appropriate filter holder systems. I found these two on this page on eBay and paid little, though if you buy retail, they can be very expensive too!
Since I want to utilize an ozone gas sterilization system with this unit, I need filter membranes that are ozone resistant. MCE (Mixed Cellulose Esters) is a good choice of filtration material. I bought a 100 pack for US$15 on eBay, brand new! I do own a medical grade ozone generator which works perfectly with this system. Ozone can be piped in through these filters sterilizing the inside of the box for 15-60 minutes. Of course, many of you may not have such a generator. If not, I would simply pipe in USP grade Oxygen in through the filter or if you do not even have that, compressed air. In theory, the filter should cleanse the incoming air. I would also give the entire contents a good spraying down with a benign antiseptic solution, like 3-6% Hydrogen peroxide before you attempt to treat the inside air with ozone, USP oxygen, or compressed air. There are many roads to Rome as they say. I have one filter holder placed at the top of the box and one at the lower end of the opposite side to allow in and out air movement.
Note on construction: I found that using tin snips is probably the best way to cut out holes and a port for the clear plastic viewing sheet. They seem to cut the plastic quite cleanly following a drawn pattern on you box presuming you can drill a starting hole. Hole saw blades are the best to use to make starting holes in you container. Use as large of a hole you have, then use snips to make the cut precise.
Technique and Summary
It is always important that one uses proper aseptic technique when working with gloveboxes. It goes without saying that first, one must utilize the autoclave to sterilize the various vials which are to be placed in the glovebox, capped from the autoclave. The solutions which are to be worked with must also be sterile. The glove box is a way to simply transfer and mix sterile formulas to sterile containers and seal for future use limiting the possibility of air contamination.
One should carefully clean and spray the insides of the glovebox with a good benign antiseptic solution. I like 3-6% Hydrogen Peroxide, but other solutions may be just as effective. Good old ethanol may be an example. One should also spray the outside of all capped sterilized vials, bottles, etc as they are placed in the glovebox. Seal and then pipe ozone or filtrated air through the box for 15-60 minutes. Shut down the air and wait a reasonable time for decontamination. Many labs prefer a positive air pressure in such gloveboxes. I don't think this is necessary for our work and will work in a still air environment.
There are many different kinds of gloveboxes. This one is a simple tent.
