Cosmetic Science Talk

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Home Cosmetic Science Talk Formulating Zinc Oxide / Calamine cream

  • Zinc Oxide / Calamine cream

    Posted by chickenskin on September 12, 2017 at 2:58 pm

    Has anyone worked with this before?  Just curious if there are any tips with working with ZnO/Calamine.  Thank you

    Bobzchemist replied 5 years ago 5 Members · 17 Replies
  • 17 Replies
  • manuksh

    Member
    September 13, 2017 at 11:34 am

    I have some and also experimenting with it.  

  • Microformulation

    Member
    September 13, 2017 at 1:28 pm

    I have worked with it as I have come up through Pharmacy Compounding. If you want some guidance on working with it, look at some of the many Formulations that are posted for Pharmacy compounding as well as the USP/NF documents. Remington: The Science and Practice of Pharmacy covers it quite a bit.

  • chickenskin

    Member
    September 13, 2017 at 3:05 pm

    @Microformulation thanks ill look at that book.  I had been attempting a petrolatum paste with ZnO at 20% with calamine.  Looks smooth until it cools and then it seems gritty.  

  • Microformulation

    Member
    September 13, 2017 at 3:31 pm

    In Pharmaceutical compounding we made small batches and honestly only when the mass produced OTC was deviated from.

    Your issues are thus;
    -If you are in the US, it is an OTC product. That means you must follow an OTC monograph and with the Regulatory requirements, it is not a Cosmetic nor is it feasible for a Cosmetic line to Market.
    -The USP OTC percentage is 8% and that was a bear to get incorporated if I recall correctly. Why 20%? In Pharmacy Compounding we were able to deviate from the OTC monograph since I prescription was provided, there were Journal citations for the Physician to justify the higher percentage and it properly became a Prescription Drug evolution. Even so, I never made higher than 12% and that was a challenge. In the end, the sensorials were not what I would have liked. 

  • Microformulation

    Member
    September 13, 2017 at 3:32 pm
  • chickenskin

    Member
    September 13, 2017 at 6:58 pm

    @Microformulation
    thanks for the info, i am aware and i am fully compliant with all otc requirements. 

  • Microformulation

    Member
    September 13, 2017 at 7:12 pm

    1-25% is in the monograph but difficult to obtain and as such, I can’t recall any products that go that high. I do recall 20% ZnO with 1% Calamine.

  • Bobzchemist

    Member
    September 13, 2017 at 7:47 pm

    If I had to guess, I’d say your ZnO was re-agglomerating. What are you using to mill this with?

  • chickenskin

    Member
    September 14, 2017 at 3:10 pm

    @Bobzchemist hey thanks for the reply.  I am just doing lab samples right now using lab stick homogenizer.  I’ll look into agglomeration.  Anything you can think of to help with that issue? Thanks

  • Bobzchemist

    Member
    September 14, 2017 at 4:15 pm

    High-speed (Cowles) disperser, 3-roll mill, colloid mill or ball mill. You could even use a muller if your sample size is small enough. Stick homogenizers don’t generate nearly enough shear force.

    There are also grades of ZnO and/or dispersing agents that should help.

  • chickenskin

    Member
    September 14, 2017 at 7:33 pm

    @Bobzchemist    Thanks for the tips.  Just to clarify I am using something like this and not a kitchen-aid stick blender.

    https://homogenizers.net/products/d500-homogenizer?nosto=productpage-nosto-1

    Is this still not enough sheer?  We have a huge colloid mill but not for lab batches.

  • Bobzchemist

    Member
    September 15, 2017 at 5:03 pm

    Well, “enough” shear should be determined by results. How are your Hegman/FOG readings?

    That homogenizer should probably work for batches up to 100 grams or so. Anything larger will likely take hours to grind small enough.

  • Bobzchemist

    Member
    September 15, 2017 at 5:07 pm
  • chickenskin

    Member
    September 20, 2017 at 2:37 pm

    @Bobzchemist

    Actually had some success using your tips, thank you.  I just increased my sheer and mixing time with my lab homogenizer.  We don’t have a hegman gauge so I can’t get any number from our plant mill.  But since this is just a lab project I don’t have to worry about that for now.  

  • Lahav

    Member
    January 4, 2018 at 11:01 am

    @Bobzchemist 

    hi, Bob maybe you can help me, I post here because the problem I am trying to solve is very similar. I formulated and manufactured anti sun organic ZnO paste for a client. Got very good results in vivo , but got 11 SPF(UVB) in vitro the problem is as I understand is with dispresing ZnO in an organic oil phase. I am trying to pick up the right equipment (colloid mill) but have a problem to find one. Do you have any insights? 

    thank you in advance

  • Microformulation

    Member
    January 4, 2018 at 2:04 pm

    You could try using a premilled dispersion. I have had some very easy products lately using the G-Block products. Nailed the SPF and Spectrum right on the first try.

  • Lahav

    Member
    January 8, 2018 at 1:01 pm

    @Microformulation 

    Thank you very much for your reply 
    It seems that every zinc oxide dispersion that produced commercially will not pass my client requirements,:(. Although found something interesting for another project,  dow sunspheres powder. Going to do some samples with it.
    I am using beeswax+jojoba+olive+coconut+cocoa butter organic mix. zinc oxide is dispersed in this faze when it is still hot. It is solid wax at 20 C. So the problem as I see it is in the dispersion of ZnO.  

  • Bobzchemist

    Member
    January 14, 2018 at 4:01 pm

    If you’re making a paste, a 3-roll mill would be your best bet.