hallo
Ale fajny bober
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I can't stop you from putting things in your eye, but I can tell you how to do it somewhat safely. (Should probably get stickied)
Sterility of Mixture:
- Contamination from environment. Sterility of Mixture:
- To prevent this:
- Make a glove box ->
- DIY a laminar flow hood ->
- OR AT THE VERY LEAST DO IT IN A LOW PARTICULATE ENVIRONMENT (Perhaps the bathroom with the ventilation fan running, and sometime after a steamy shower to have less dust in the air.
- Contamination from manufacturing or transport.- To prevent this:
- Don't cheap out! Buy pharmaceutical grade materials with high purity ratings. Use a chemical supplier not Amazon.
- Contamination from equipment and yourself.- To prevent this:
- Boil all glassware used or use disposable equipment.
- Use only distilled water as a mixture ingredient.
- Wear a facemask and gloves.
- Optional: Filter solution through 0.22 micron syringe filter as you transfer to your storage vial.
Consistency of Mixture:
- You must ensure homogeneity of mixture.- To ensure this:
- Make sure everything is actually dissolving first of all. If not, increase the heat slightly or add more solvent. You can also use an ultrasonic bath, but those can be expensive.
- Expensive but gold standard is a high-sheer mixing machine.
Biological Interactions:
- pH (CHEMICAL BURN RISK) - To prevent this:
- Check the pH of your mixture with a pH test strip or pH meter. The normal pH of the human tear film is about 7.4. Anything outside of 6.5 and 8.5 should be avoided as you start to risk chemical burns.
- If your solution is outside of this range, find pH buffer solutions (that are safe for your use) and add them drop-wise until you enter the range.
- Boric Acid and Sodium Borate Buffer is a buffer set that can be used as long as it does not interact unfavorably with the rest of your compound.
- Osmolarity (EYE IRRITATION AND DAMAGE RISK)
- This refers to the number of solute particles per liter of solution, typically measured in milliosmoles per liter (mOsm/L) with an osmometer.
- Both hypertonic and hypotonic solutions can disrupt the delicate balance of the eye’s surface, potentially causing damage to the corneal epithelial cells and other ocular tissues.
- You need an Isotonic Solution. For eye drops, this means matching the osmolarity of natural tears, which is approximately 300 mOsm/L.
- Suppose you have prepared a 1% solution of a drug for eye drops. To adjust the osmolarity:
- Calculate Required Additive:
- You need to know the osmolarity of your initial solution. Let's say it's 200 mOsm/L, and you need to increase it to 300 mOsm/L.
- Add Sodium Chloride:
- If using sodium chloride (NaCl), you can add it to the solution. The formula for adjusting osmolarity is based on the principle that 0.9% NaCl solution is isotonic (300 mOsm/L).
- Calculate the amount of NaCl needed to reach the desired osmolarity:
- Each 1 gram of NaCl added to 1 liter of water increases the osmolarity by approximately 17.1 mOsm/L.
- If your solution is 100 mOsm/L short, you would need to add about 5.85 grams of NaCl per liter (100 mOsm/L / 17.1 mOsm/L per gram)
- If you don't want to shell out for an osmometer than you can use the known Osmolarities of your solutions and estimate it or you can do the following:
- Freezing Point Depression Test or Boiling Point Elevation Test
- Storage
- If you want to store your drops for longer than 24 hrs then consider adding a preservative like Benzalkonium chloride.
- Label everything appropriately and store in the refrigerator or at a specific temperature if required.
- Highly recommend getting an eyedropper bottle to store the final mixture.
- Side Effects
- If you apply the drops and you experience burning or itching flush with water immediately, and do not vigorously rub your eyes.
- Burning in this situation is a bad thing and no amount should be tolerated.
- Give yourself a tiny prick on your skin and put a small amount of the mixture there to test for any potential allergic reactions. (Leave for 12 minutes.)
