mdhx3
Banned
For those interested in letrozole solution:
From the research I have done, it seems that DMSO is the only non-toxic solvent for letrozole solution. I have read some posts about "dissolving" letrozole in ETOH and water; but letrozole is actually insoluble in both ETOH and water. So, at best, those using ETOH or water are getting a suspension. Suspensions are notoriously unreliable for small dose titrations (even pharmaceuticals); so solution is a much better method.
The solubility of letrozole in DMSO is 57mg/ml for a saturated solution in vitro. That would be far too concentrated to use; so I made my own recipe.
The concentration of 2.5 mg/ml seems to be an easy concentration to use, as it is within the nominal dosage range and is easily titratable.
The only storage life information I could find is for letrozole solid (powder): 3 years @-20C (-4F). Solution would not be practical at this temperature, nor do I have access to a liquid nitrogen cryotank. So, in my estimation, the batches should be made in an amount that could be used within 6 months or less. I also think the solution should be refrigerated.
For the sake of simplicity I mixed 250mg at 2.5 mg/ml, yielding 100ml of solution. This volume and concentration would be usable for most people; and would likely not be wasted during the arbitrarily assumed 6 month refrigerated storage life.
My method of mixing is of my own design:
I use an analytical balance (accurate to 1mg), a hotplate with integrated magnetic stirrer, (1) 50ml graduated cylinder, (1) 100ml glass beaker, (1) 250ml glass beaker, and (1) 4oz clear round dropper bottle. All of my glassware is sterilized in the autoclave. It probably isn't necessary for the oral solutions; but I am super "type-A" about procedure.
Steps:
1) measure 250mg of raw letrozole powder
2)pour 30ml DMSO into the 100ml beaker and place on the hotplate stirrer
3) heat the DMSO to 125F with the stirrer on
4) slowly add the letrozole powder until the solution is clear
5) remove from heat and pour that solution into the 50ml graduated cylinder
6) record the volume of the solution in the graduated cylinder (mine was 32.25ml)
7) pour the solution into the 250ml beaker and place it back on the hotplate stirrer
8) subtract the number you recorded of the solution volume from 100ml; and add that amount (mine was 67.75ml)of WARM distilled water to the solution on the hotplate
9)allow the solution to mix for 3 minutes and remove it from the hotplate to cool
10) pour the cooled solution into the 100ml clear dropper bottle.
You now have letrozole solution in a 2.5mg/ml concentration.
Mine has been in the refrigerator for 3 days with no change in color or clarity and with no sedimentation. It appears to be a true stable solution.
I hope this is helpful.
From the research I have done, it seems that DMSO is the only non-toxic solvent for letrozole solution. I have read some posts about "dissolving" letrozole in ETOH and water; but letrozole is actually insoluble in both ETOH and water. So, at best, those using ETOH or water are getting a suspension. Suspensions are notoriously unreliable for small dose titrations (even pharmaceuticals); so solution is a much better method.
The solubility of letrozole in DMSO is 57mg/ml for a saturated solution in vitro. That would be far too concentrated to use; so I made my own recipe.
The concentration of 2.5 mg/ml seems to be an easy concentration to use, as it is within the nominal dosage range and is easily titratable.
The only storage life information I could find is for letrozole solid (powder): 3 years @-20C (-4F). Solution would not be practical at this temperature, nor do I have access to a liquid nitrogen cryotank. So, in my estimation, the batches should be made in an amount that could be used within 6 months or less. I also think the solution should be refrigerated.
For the sake of simplicity I mixed 250mg at 2.5 mg/ml, yielding 100ml of solution. This volume and concentration would be usable for most people; and would likely not be wasted during the arbitrarily assumed 6 month refrigerated storage life.
My method of mixing is of my own design:
I use an analytical balance (accurate to 1mg), a hotplate with integrated magnetic stirrer, (1) 50ml graduated cylinder, (1) 100ml glass beaker, (1) 250ml glass beaker, and (1) 4oz clear round dropper bottle. All of my glassware is sterilized in the autoclave. It probably isn't necessary for the oral solutions; but I am super "type-A" about procedure.
Steps:
1) measure 250mg of raw letrozole powder
2)pour 30ml DMSO into the 100ml beaker and place on the hotplate stirrer
3) heat the DMSO to 125F with the stirrer on
4) slowly add the letrozole powder until the solution is clear
5) remove from heat and pour that solution into the 50ml graduated cylinder
6) record the volume of the solution in the graduated cylinder (mine was 32.25ml)
7) pour the solution into the 250ml beaker and place it back on the hotplate stirrer
8) subtract the number you recorded of the solution volume from 100ml; and add that amount (mine was 67.75ml)of WARM distilled water to the solution on the hotplate
9)allow the solution to mix for 3 minutes and remove it from the hotplate to cool
10) pour the cooled solution into the 100ml clear dropper bottle.
You now have letrozole solution in a 2.5mg/ml concentration.
Mine has been in the refrigerator for 3 days with no change in color or clarity and with no sedimentation. It appears to be a true stable solution.
I hope this is helpful.
