compounding HOTLINE

Q: The following formulation yields a gritty preparation forme. Could you offer some suggestions for improvement?

Gabapentin 5%

Lidocaine 15%

Ketoprofen 10%

Dimethyl sulfoxide (DMSO)5%

Pentravan qsad 30 g

Apply bid.

A: Elegance is the key to the evaluation of a compoundedpreparation and is the "art" side of pharmaceuticalcompounding. Elegance begins on the balance, in the mortar,and on the ointment slab. Adherence to technical proceduresis important and is supported by artful performance of theprocess. Accurate, precise weighing, followed by reduction ofpowdered ingredients to impalpability (or nearly so)—using aceramic or Wedgwood mortar and pestle (or an appropriatespatula and solid smooth surface)—is vital to preparation of a"smooth" ointment. In addition, an appropriate wetting agentshould be employed to ensure dispersion of the powder(s) inthe vehicle (ointment base).

I have a recommendation: reduce the powders to fine,impalpable consistency with a ceramic or Wedgwood mortarand pestle; add a small amount of DMSO with trituration tomake a paste; then continue to add the rest of the DMSO withtrituration. Transfer the resultant mass to a slab, and, usinggeometric dilution technique, levigate with Pentravan until allingredients are combined.

Q: We have an order for carvedilol 0.4 mg (for a child) andwish to prepare a suspension from the tablet. Do you haveany method for this?

A: Only one study related to the question was found: vonMöllendorff E, Reiff K, Neugebauer G. Pharmacokineticsand bioavailability of carvedilol, a vasodilating beta-blocker. Eur JClin Pharmacol. 1987;33(5):511-513.

The shelf stability or beyond-use date for the suspension wasnot reported. As with other similar situations, the conservativeapproach would be to make powder papers or capsules to beopened and mixed with a beverage (preferably water) at the timeof administration.

Mr. Erickson is director of professional affairs at Gallipot Inc.

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