Pharmacy Times

Your Compounding Questions Answered

Author: Martin A. Erickson III, RPh

Q: I am interested in compounding a glycolic 30% body lotion. Also, what is the percentage for facial peels using glycolic acid crystals?

A: Glycolic acid (hydroxyacetic acid) is an odorless, hygroscopic crystalline substance with a melting point of 80°C. It has molecular weight 76.05 and is soluble in water, methanol, alcohol, acetone, acetic acid, and ether. The pH of various aqueous glycolic acid solutions is: 0.5% pH 2.5; 1% pH 2.33; and 10% pH 1.73. It is a constituent of sugar cane juice and can be produced commercially either by reacting NaOH with monoacetic acid or by electrolyte reduction of oxalic acid. It is a mild irritant to skin and mucous membranes. It is this irritant characteristic that makes it useful as a skin peel. A relatively stable preparation of glycolic acid in hydrophilic ointment USP with pH adjustment to 3.5 using sodium hydroxide solution has been reported. While a specific beyond-use date (BUD) was not reported because the study focused on freeze-thaw cycles, a 30 days refrigerated BUD could reasonably be assigned to this preparation.

An extemporaneously compounded facial lotion has been reported:

Suggested formulation:
Glycolic acid 70% solution (aqueous).................................1.5 mL
Veegum, 5% colloidal solution............................................5.0 mL
Methylparaben..................................................................0.050 gm
Propylparaben...................................................................0.025 gm
Purified water q.s. ad......................................................100.00 mL

Suggested preparation method:
  1. Prepare the Veegum 5% colloidal solution in a graduated cylinder.a
  2. Dissolve the methylparaben and propylparaben in 94 mL of purified water. Heat to approximately 70 to 75° C to facilitate dissolution.
  3. Allow the paraben solution in (2) to cool to room temperature.
  4. Add the glycolic acid to the solution in (3).
  5. Neutralize the solution in (4) with ammonium hydroxide 28% solution, adding it dropwise with stirring until the pH is about 4 to 4.5.
  6. Add the Veegum 5% colloid to the neutralized solution in (5) and mix thoroughly. Rinse the cylinder with the solution in (5) and return the material to the preparation.
  7. Bring the mixture in (6) to final volume (100.00 mL) with purified water.
  8. Package, label, and dispense. Consider “External Use Only,” “Caution: Irritant” (or similar). USP <795> specifies BUD 14 days, refrigerated for aqueous extemporaneous preparations.
aVeegum 5% colloidal solution: Disperse 5 gm of Veegum in a small amount of water; stir vigorously to make a smooth paste. Bring to volume with purified water and continue stirring. When the colloid is allow to stand at room temperature, a smooth, creamy mixture is observed. Occasionally, a 40% solution is wanted. In these cases, note that addition of neutralizing ammonium hydroxide 28% solution to pH 4 to 4.5 will be necessary.

E-mail your compounding questions to compounding@PharmacyTimes.com.


Mr. Erikson is director of professional affairs and director of professional services at Gallipot, a Fagron company.