Transport of hydrophilic or charged molecules through the skin is especially difficult attributable to the lipid-rich nature of the stratum corneum and its low water content. This layer is composed of about 40% lipids, 40% protein, and only 20% water. Transport of  lipophilic drug molecules is facilitated by their dissolution into intercellular lipids around the cells of the stratum corneum. Absorption of hydrophilic molecules into skin can occur through "pores‟ or openings of the hair follicles and sebaceous glands, but the relative surface area of these openings is barely 1% of the total skin surface. This small surface area limits the amount of drug absorption.

An understanding of the transport behavior of drugs into the emulsion and through the

membrane is important for designing an effective topical product.

Penetration depends on wether your active is water soluble or not. As you are using a water/alcohol solution I presume it is. I would bet that wetting the scalp before applying the product would not help. I would have a look to Johann Wiecher´s papers on the subject. He was a good firend, but unfortunatelly died a few years ago.

You may find a free presentation of the subject in:

http://www.ipapharma.org/pdf/speaker/better%20efficacy.pdf

Hope I have helped you

Federico Svarc

Thank you very much Federico for your answer. I attended one of Dr Wiecher's presentations at the Sociedad de Químicos Cosméticos in Barcelona. I was really sorry to hear about his death.

I think that in the scalp, the effect then is mainly through the absorption through the hair follicles and in the case of hair growth lotions is probably enough...?

Maybe.....

If you could "mark up" somehow the active molecule and look for penetration through a small excision of the scalp....you could get a positive experimental answer.

Or "in vitro" with a Franz cell, but you need a piece of representative membrane...

Not easy to get.

Pig skin in my experience is not representative.

Hi Merce: 

Today I received the invitation below by Croda.

There is a product, Arlasolve DMI (Dimethyl Isosorbide, CAS No. 5306-85-4), who could enhance the penetration of your active molecule.

It could help you to improve your formulation efficacy.

Could you keep me informed?

Thank you

Federico

Hi Everybody,

We are excited to announce that we will hold a LIVE eSeminar “Enhancing Skin Penetration” (Part 1) on 29th April.

It will focus on the skin penetration enhancement benefits of Super Refined Arlasolve DMI, clearly showing the new and innovative MALDI-MS imaging.

What will the eSeminar include -

·         Super Refined Arlsolve DMI benefits

·         Experiments with Franz Cells diffusion

·         The new MALDI-MS imaging technology

·         Analytical experiments

·         Live Q&A session

The e-seminar will be presented at separate times as follows in Portuguese and Spanish:

Portuguese

When – 29th April, 10:00 am EDT

11:00 am (Horário de Brasília)

Title – Aumentando a Penetração Cutânea

Spanish

When – 29th April, 1:00 pm EDT

12:00 pm - Mexico

12:00 pm - Colombia, Ecuador, Peru

1:00 pm -  Miami

 2:00 pm -  Chile, Argentina

Title – Aumentando la Penetración Cutánea

Promotional Activity

A customer mailshot is currently being prepared – this will be sent out to our Croda Direct extranet mailing list, and a copy of all recipients will be shared with you to ensure you have the opportunity to share it with contacts who are not on our extranet mailing list yet.

We want to make this a RECORD EVENT for LatAm.  

As we know the key to success of this eSeminar will be getting customers to sign up which as we know depends on our wonderful and enthusiastic Sales Team making the contact and following up the customer mailshot prior to the event. 

Let´s Roll !!!!!!!!!

Mike

Michael Dixon

Crop and Health Care Marketing Manager

Croda do Brasil

Mobile +55 19 99453 8485

[email protected]

www.croda.com

Hi Federico:

This product sounds like a good idea. I will check it out.

Thank you for your help

Merce

Good Answer Federico Svarc