How to compound topical menthol products?

[PASSNIKI]

I've been prepping for the upcoming NYS compounding exam, and in my practice problems, there are some creams and ointments that calls for menthol crystals. From what I can tell, you don't use a levigating agent to wet the crystals first, so my question is do you directly levigate the crystals into the ointment or cream base? Do the crystals melt once it's incorporated? Obviously we're looking to eliminate any grittiness, so if the crystals don't melt, then it's not a good product. Or do you crush the crystals in the wedgewood mortar first?

I understand that if both menthol and camphor crystals are used, then we can make an eutectic mixture, but what do you do in situations that only call for one crystal type?

Please help!

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[PASSNIKI]

Or do you melt the crystals first? I will be taking the exam at St. John's, so any tips on how to go about compounding this product will be greatly appreciated!

 

[Eugenia]

I've been prepping for the upcoming NYS compounding exam, and in my practice problems, there are some creams and ointments that calls for menthol crystals. From what I can tell, you don't use a levigating agent to wet the crystals first, so my question is do you directly levigate the crystals into the ointment or cream base? Do the crystals melt once it's incorporated? Obviously we're looking to eliminate any grittiness, so if the crystals don't melt, then it's not a good product. Or do you crush the crystals in the wedgewood mortar first?

I understand that if both menthol and camphor crystals are used, then we can make an eutectic mixture, but what do you do in situations that only call for one crystal type?

Please help!

 

[Eugenia]

Whoopsie. I did not mean to quote the previous post. Anyways, menthol crystals are easily incorporated into the ointment base. You place your spatula over the crystal and apply some pressure in order to break down the crystal (press up and down) When get some ointment base (100 mg-200 mg) and mix. The mix becomes homogeneous (not gritty at all) because menthol crystals start melting right away resulting in a nice elegant product. Creams with menthol are harder to make though because menthol is lypophilic. Larger menthol crystals tend to jump off the slab when you try to break them with spatula, so practice more. Good luck on the NY part III next week!

 

[Eugenia]

And don't use the levigating agent per Dr Cutie. You levigate with a portion of your base.