Formulation Advice for Topical Ointment Containing Keratolytics

Hello,

I suffer from a very rare skin condition called Pityriasis Rubra Pilaris.  It is characterized by keratoderma and psoriasis-like scaling.  Unfortunately since it is so rare (approx. 1 in 400,000), research and development for treatment options is very sparse.

A Dermatologist who has worked extensively with such cases (Dr. Andrew Griffiths) advises in this presentation (apologies for the poorly formatted PDF, I am not the author):

http://prpsurvivalguide.org/wp-content/uploads/2017/05/Dowling-Oration-2003-Liverpool-England.pdf

that a topical treatment containing "keratolytics" is helpful (page 27).

Screenshot of the page here:

https://imgur.com/a/iZM1Fzg

The formula is given as follows:

* Urea 5%
* Salicylic acid 5%
* Propylene glycol 20%
* Liquid paraffin 20%
* Emulsifying ointment to 100%

It is a pretty straight forward formula, however I would appreciate someone with the proper background in formulation to give their input on creating this ointment.

I have some basic background using very simple formulas such as

* beeswax, shea butter, mineral oil, and petrolatum with phenonip preservative

* oil-in-water with petrolatum, mineral oil, emulsifying wax NF (cetearyl alcohol and polysorbate 80), water, glycerin, beeswax, etc., with germaben II as preservative

My take on creating the "keratolytic" ointment would be first:

* find appropriate source for urea and salicylic acid
* evaluate possible safety concerns in handling above ingredients 
* determine if a preservative is required and if so which one and at which concentration
* determine what is meant by "emulsifying ointment"

His background is most likely from the pharmaceutics and compounding perspective and the 'emulsifying ointment' would be one of these bases:

https://pharmlabs.unc.edu/labs/ointments/bases.htm

I am thinking that using aquaphor or a similar pre-made o/w base could be appropriate.

If anyone is able to comment on my approach I would be appreciative.

Thank you.  

 

Comments

  • Just wondering, must it be 5% Salicylic acid? Because it's can be very difficult to solubilize. 
  • jemolian said:
    Just wondering, must it be 5% Salicylic acid? Because it's can be very difficult to solubilize. 

    It is probably pretty flexible.  I imagine that, as many doctor's tend to do, he looked up the max safe dosage and is using that as long as it doesn't cause adverse effects for the patient. 
  • Couple of questions.
    1. Why do you have to formulate the ointment yourself, is 12% Lactic acid cream or 20% urea cream not available in the hospital?
    2. Have you consult your doctor about using this ointment, is your condition not improved with normal Vaseline, should you jump start to keratolytic dressing? Or is your doctor planning on keratolytic with topical corticosteroids? 
    3. Are you confident in your formulating skill? Should you better have a pharmacist prepare the formulae?



  • Pattsi said:
    Couple of questions.
    1. Why do you have to formulate the ointment yourself, is 12% Lactic acid cream or 20% urea cream not available in the hospital?
    2. Have you consult your doctor about using this ointment, is your condition not improved with normal Vaseline, should you jump start to keratolytic dressing? Or is your doctor planning on keratolytic with topical corticosteroids? 
    3. Are you confident in your formulating skill? Should you better have a pharmacist prepare the formulae?


    Very appropriate questions.  Here are the answers:

    1. a. Dealing with a chronic skin problem which requires multiple daily topical applications of top-tier cosmeceuticals is very very expensive -- $20 for 250g of one of them, which is applied over large parts of the body.  The ingredients for these are not exotic and I see it as the equivalent of going to a nice restaurant every day for all meals instead of cooking your own.

    1. b. The formulation would require a compounding pharmacy.  This would require a doctor to prescribe it -- even though the ingredients themselves are available individually to consumers and are not restricted.  This is equivalent to getting prescribed an 800mg Ibuprofen pill when you could buy a bottle of 200mg pills and take four of them. 

    2. a. I have not.  This condition is very rare and there is barely any evidence based research on treatments -- without this doctors are (understandably) hesitant to proceed down unfamiliar treatment paths. 

    2. b. In the USA, even with good insurance, it is a bureaucratic nightmare to have non-standard treatments approved.  To get them to approve a compounding pharmacy to regularly provide a mixture of over-the-counter ingredients for a dermatological condition will be -- I am quite sure -- a lesson in frustration and possibly futility.  And if it does get approved I still have to pay an unknown out-of-pocket cost for it.

    2. c. Vaseline is indeed a great occlusive and emollient.  However it is not effective alone at mitigating my symptoms, which involve large patches of very itchy inflamed skin over 80% of my lower body, certain parts of my face and scalp, and a good portion of my chest and back.  I don't know if you have covered your body in petrolatum before, but it destroys your clothes and furniture and generally makes life unpleasant and requires application over wet skin to be effective.  It also makes the bathroom floor a fall hazard and will clog your drains without mercy.

    3. a. I am confident that I can follow instruction and data and that those are available to me -- provided that I am responsible and diligent. 

    3. b. If it appears that using a pharmacy is the best course of action, I will pursue that.  At this time, however, I can find no positive benefit to having a pharmacist compound ingredients if I can do it in a safe, consistent, effective, and economically advantageous manner.
      
    Thanks
  • I see, USA - your healthcare system is a nightmare.
    If you choose to do so then I would suggest in order
    1. 10% - 20% Urea cream.
    2. 10% (w/w) Lactic acid cream.
    3. Salicylic acid cream or solution.
    **Salicylic acid is harsh - only seen 1 study suggesting Salicylic cream has better tolerance than AHA cream in Psoriasis management.

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