Q: I am a pharmacist in Argentina. I am often requested toprepare a cream containing 15% phenylalanine, apparentlyused for repigmentation of the skin. The concentration exceedsthe solubility limit. Should I prepare a suspension and then mix itwith the base cream? Or can I dissolve it with something else?
A: Phenylalanine is only sparingly soluble in water. The productwill be a suspension. If you choose to use a vanishingcream (oil in water) or a cold cream (water in oil) as the vehicle,refer to the label to determine the levigating agent to employ.Usually, glycerin or propylene glycol is present in the vehicleand will therefore be compatible if used as the levigating agent.Phenylalanine powder is crystalline. Comminuting (grinding)the powders in a ceramic or Wedgwood mortar before incorporatingthem into the vehicle, making a paste with the chosenlevigating agent, and then using geometric dilution technique toincorporate the paste into the vehicle should produce an elegantcompound.
References found used phenylalanine 10% to 15% to treatvarious skin conditions, including vitiligo. In one reference, theadministration of phenylalanine (Phe) combined with ultravioletA (UVA) exposure was found to be effective in treating vitiligo.Twenty-one patients with vitiligo were divided into 2groups. In both groups, the patients were treated with oral LPhein a dose of 100 mg/kg of body weight and with UVAexposure. In one group, a cream containing 10% L-Phe wasapplied to the vitiliginous areas. The best results occurred inthat group. No side effects were found in either group (AntoniouC, et al. Int J Dermatol. 1989;28(8):545-547).
Mr. Erickson is director of professional affairs at Gallipot Inc.
E-mail your compounding questions email@example.com