Formulation in Pharmacy Practice  eMixt

Thyroxine (levothyroxine)
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Levothyroxine sodium has an aqueous solubility of 150 micrograms per mL at 25C.
The compound is also sensitive to light and pH.1

Short term stability has been reported in a water/glycerol1 and a 70% sorbitol based mixture.2 Compounded suspensions appear to have very limited stability. Stability in commercial bases such as Ora-Plus has not been determined.

 


Formula 1

Thyroxine 25 micrograms per mL
 
Levothyroxine sodium tablets 100 micrograms 25 
Glycerol 40  mL
Water to   100  mL
Method:
  1. Grind up tablets.
  2. Mix up with 10mL aliquots of glycerol until all
    the glycerol is used up.
  3. Bring up to volume (100mL) with water.
Stability:  8 days.
Storage:  Stable under refrigeration and at room temperatures (temperatures above 27C should be avoided).
Store in amber bottles.  Preservative not necessary with such a short expiry date, especially if refrigerated.
 
 

 
References/bibliography
  1. Boulton D.J., Fawcett J.P., Woods D.J.  Stability of an extemporaneously compounded levothyroxine sodium oral liquid.  Am J Health Syst Pharm 1996; 53: 1157-61.
  2. Alexander KS, Kothapalli MR, Dollimor D.Stability of an extemporaneously formulated levothyroxine sodium syrup compounded from commercial tablets. Int J Pharm Compound;1997:60-63
  3. Stabilis Database Levothyroxine

 

Formulation in Pharmacy Practice - eMixt
Page updated June 2014