Permeability/absorption abilities of skin

[Guest guest]

>Why is Jojoba wax/oil assimilated by the body so well?

Jojoba oil spreads quickly but I don't think that Jojoba Oil is

assimilated by the body nor have I seen any data that would lead me

to believe that it does. If Jojoba Oil was assimilated by the body,

it would be affecting a function of the body and, by definition,

would be a drug.

Here's a good source of information on Jojoba Oil

Cosmetic Chemistry of Natural Jojoba

http://www.purcelljojoba.com/english.pdf

, another CosmeticInfo member believes that some cosmetic

ingredients penetrates the skin

http://health.groups.yahoo.com/group/Cosmeticinfo/message/23049

Perhaps she'll see your post and will provide her insight and a

different perspective.

>I've been using

>progesterone cream to regulate my menstrual cycle and it works so

>well, I want to know more about the permeability of skin. Why are

some

>skin problems better served by oral medications or topical

ointments?

I've always believed that, as a general rule, oral administration of

drugs was superior to transdermal patches or topically applied

drugs. Topically applied drugs are slower to penetrate into the

body but that do have the advantage of localized activity.

I've always believed that eating foods that contain essential fatty

acids was better than applying a lotion that contained essential

fatty acids.

However, in some cases, topical application of Vitamin E is faster

and better than taking a capsule or eating food high in Vitamin E.

This is especially true after the skin is exposed to natural

sunlight.

This was described in a recent article

Delivery of Vitamin E to the skin by a novel liquid skin cleanser:

Comparison of topical versus oral supplementation

Amir Tavakkol, Zeenat Nabi, Nadia Soliman and G. Polefka

Colgate-palmolive Company, 909 River Road, Piscataway, NJ 08855

J. Cosmet. Sci. 55, 177-187 (March/April 2004)

>When we put things on our body which ones are absorbed? How? How

fast?

>How much? Was my mom right when she said I was poisoning myself

when I

>wrote with pen ink on my skin? How can those birth control and

>nicotine patches work in a time release way?

These patches use certain chemicals that help the drugs to penetrate

the skin and they usually use high concentrations of the drugs that

help the rate of diffusion across the skin's barrier.

>Is it true that plain water is drying to the skin,

I don't think that is an issue under normal conditions. Water is a

major component of the body.

>wax creates a barrier on the skin and water/oil emulsions are

aborbed? How so?

Waxes and oils will create a barrier on the skin and will reduce the

rate at which the water leaves the body. This process of water loss

is call " transepidermal water loss " or TEWL.

>Well, I've got a zillion questions on this subject, but maybe

someone

>can get me started in the right direction?

A good place to start your search would be the CosmeticInfo message

archives and the CosmeticInfo files area.

These links are found in a html document found in the CosmeticInfo

files area:

http://health.groups.yahoo.com/group/Cosmeticinfo/files/Misc/Cosmetic

Info_Links.htm

The life cycle of a horny cell

http://www.scf-online.com/english/35_e/frontpage35_e.htm

The protective functions of the skin

http://www.scf-online.com/english/36_e/skinfunk36_e.htm

Moisturization & How Thirsty Is Your Skin?

http://www.nyscc.org/news/archive/tech1003.htm

Moisturizers

http://www.emedicine.com/derm/topic506.htm

Better skin protection with new barrier creams

http://www.scf-online.com/english/31_e/barriercreams31_e.htm

Cosmeceuticals

http://www.emedicine.com/derm/topic509.htm

When ever I'm look for technical information, I like to search

MEDLINE

http://gateway.nlm.nih.gov/gw/Cmd

or PubMed

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi

" MEDLINE is NLM's database of indexed journal citations and

abstracts now covering nearly 4,500 journals published in the United

States and more than 70 other countries. Available for online

searching since 1971, MEDLINE includes references to articles

indexed from 1966 to the present. New citations are added weekly.

All citations in MEDLINE are assigned MeSH Terms and Publication

Types from NLM's controlled vocabulary. MEDLINE citations and

abstracts are available as the primary component of NLM's PubMed

database, which is searchable via the Internet.

In addition to providing access to MEDLINE, PubMed provides access

to:

The out-of-scope citations (e.g., articles on plate tectonics or

astrophysics) from certain MEDLINE journals, primarily general

science and chemistry journals, for which the life sciences articles

are indexed for

MEDLINE.

Citations that precede the date that a journal was selected for

MEDLINE indexing.

Some additional life science journals that submit full text to

PubMedCentral and receive a qualitative review by NLM. "

http://www.nlm.nih.gov/pubs/factsheets/dif_med_pub.html

For example, ig you search PubMed for the search terms

transdermal penetration

you'll get 532 literature citations.

Here's just one citation that was at the top of the list:

---------------------

Crit Rev Ther Drug r Syst. 2004;21(2):97-132.

Penetration enhancement of transdermal delivery--current

permutations and limitations.

Purdon CH, Azzi CG, Zhang J, EW, Maibach HI.

College of Pharmacy, University of South Carolina, Columbia, South

Carolina 29208, USA.

In order to achieve enhanced topical drug delivery, it is necessary

to make physical or biomolecular structural alterations to the

stratum corneum by suitable techniques or by the use of specific

chemical agents or drug carriers. The role of the chemical

penetration enhancer is to reversibly alter the barrier properties

of the stratum corneum by disruption of the membrane structures or

by maximizing drug solubility within the skin. Alternatively,

permeant delivery to the dermal vasculature using one of several

physical methods to reduce diffusional resistance within the skin

may be used to promote drug penetration. In the present article, we

summarize the major facets of the diverse spectrum of penetration

enhancement techniques that include modification of the stratum

corneum, lipid-based delivery systems, drug/vehicle interactions,

bypassing the stratum corneum, and electrical techniques of

enhancement.

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?

cmd=Retrieve & db=pubmed & dopt=Abstract & list_uids=15202928

---------------------

and if you search PubMed for

transepidermal water loss

you'll get 784 hits.

Once again, here is just one example:

---------------------

Br J Dermatol. 2004 Jun;150(6):1142-7.

Irritation potential of bath and shower oils before and after use: a

double-blind randomized study.

Loden M, Buraczewska I, Edlund F.

ACO Hud AB, SE-194 26 Upplands Vasby, Sweden. marie.loden@...

BACKGROUND: Difficulties in avoiding weak irritants may contribute

to chronic contact dermatitis. A large variety of shower and bath

oils are claimed to be suitable for use on dry skin because of their

mildness and because they deposit a protective oil film on the

skin. OBJECTIVES: The aim of the present study was to investigate

possible differences in the irritation potential of eight shower or

bath oils and to investigate whether surfactant residues may form a

reservoir of irritant substance on the skin. PATIENTS AND METHODS:

The study was double-blind and randomized using healthy human

volunteers. The inherent capacity of the products to induce

irritation was determined using conventional patch test techniques.

Detection of potentially irritant residues was done by occlusion of

the treated and rinsed skin area, followed by evaluation of the

biological response. Instrumental measurements of transepidermal

water loss and superficial skin blood flow served as indicators of

the injurious effects of the products. RESULTS AND CONCLUSIONS: The

results showed large differences between the products in irritant

potential. Some did not irritate skin more than water, whereas

others demonstrated considerably damaging effects. Moreover, the

study proved the presence of barrier-impairing residues on the skin

after rinsing with water. Thus, instead of protecting the skin, some

formulations may induce subclinical injuries and delay skin barrier

function recovery with prolonged risk for patients with eczema.

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?

cmd=Retrieve & db=pubmed & dopt=Abstract & list_uids=15214901

---------------------

Have fun.

Maurice

--------------------------------------------------------

Maurice O. Hevey

Convergent Cosmetics, Inc.

http://www.ConvergentCosmetics.com

-------------------------------------------------------

[Guest guest]

> I've always believed that, as a general rule, oral administration of

> drugs was superior to transdermal patches or topically applied

> drugs. Topically applied drugs are slower to penetrate into the

> body but that do have the advantage of localized activity.

> I've always believed that eating foods that contain essential fatty

> acids was better than applying a lotion that contained essential

> fatty acids.

Well Maurice it just popped in my head but a few years back when I

still breastfed my daughter, I took antibiotics for an ear infection,

which was followed by a yeast infection on one breast, which then

spread to the other (of course!). Anyhow, my doctor gave me yeast

cream to apply to the breasts. The pediatrician gave me oral

medication to give to my daughter, I was also advised that painting

Gentian Violet on my breast and in the baby's mouth would cure the

yeast but be very messy, so the oral and topical meds were " better " .

So time went by, meds are getting used up and no sign of relief in

sight. I was itching like crazy and ready to wean! Then another

nursing mother told me, forget the topical and oral meds, just cut

sugar out your diet completely for a few weeks and take a daily garlic

supplement. So I did that and it really worked, in fact, I'd swear I

could feel my skin tingly-itching when I cheated and had a soda,

before I totally bucked the sugar. I don't know that the garlic

helped, but I sincerely believe cutting the sugar helped.

I've definitely come to question what I put in and on my body later in

life than I wish, but I can surely do it now and pass it on to my

daughter!

> When ever I'm look for technical information, I like to search

> MEDLINE

> http://gateway.nlm.nih.gov/gw/Cmd

> or PubMed

> http://www.ncbi.nlm.nih.gov/entrez/query.fcgi

Duh! I didn't think to look there.....I used these sites fairly

extensively when my mother was ill last summer, never thought to look

up skin there!

Thanks again Maurice! :~)

[Guest guest]

>Nothing we make as cosmetic formulators is ever truly absorbed into the

>skin. You wouldn't want it to be. The moisture barrier exists in the

>very top layers of the skin, so moisturizers only need to interact with

>the skin at that very superficial level. Anything else, and you'd be

>mucking around with the internal structure of the live skin layers and

>could easily do more harm than good!

>

>Elaine

Does this include parabens and other preservatives. The ongoing complaint about

them is that they are absorbed into the bloodstream and accumulate.

Also, how does this explain the effectiveness of topical pain relievers? This

seems to contradict the claims made about emu and similar oils being absorbed

deeply into the skin.

Gillian

[Guest guest]

>According to Clin Dermatol. 2001 Jul-Aug;19(4):489-501. Percutaneous absorp=

>tion and

>delivery systems:

> " ...a lipophilic vehicle will easily penetrate facial skin where the SC is =

>lipid rich (1020% by

>weight....This membrane (stratum corneum) allows no molecule to pass readil=

>y, but nearly

>all materials penetrate to some extent. "

ti P, Ruocco E, Wolf R, Ruocco V. Related Articles, Links

Percutaneous absorption and delivery systems.

Clin Dermatol. 2001 Jul-Aug;19(4):489-501. Review. No abstract available.

PMID: 11535394

You must have a copy of this issue of Clinics in dermatology. This particular

issue looks like it was devoted to cosmetics.

>In fact, consider the case of sunscreens: " Functional ingredients like UV f=

>ilters, for

>example, should remain on the skin surface. If they penetrate, they would b=

>e beyond their

>site of action and so, from a functional point of view, skin penetration of=

> these ingredients

>is not desired. "

Translated that means if a sunscreen active does not stay on the surface of the

skin, it won't work as a sunscreen.

>Well:

[i had to find this abstract because your formating made reading difficult.]

J Chromatogr B Analyt Technol Biomed Life Sci. 2004 Apr 25;803(2):225-31

Liquid chromatographic assay for common sunscreen agents: application to in vivo

assessment of skin penetration and systemic absorption in human volunteers.

Sarveiya V, Risk S, Benson HA.

Faculty of Pharmacy, University of Manitoba, Winnipeg, Man., Canada.

The purpose of the present study was to develop a reverse-phase high-performance

liquid chromatographic (HPLC) assay for quantifying four common sunscreen

agents, namely 2-hydroxy-4-

methoxybenzophenone, 2-ethylhexyl-p-methoxycinnamate, 2-ethylhexylsalicylate

(octylsalicylate) and salicylic acid 3,3,5-trimethcyclohexyl ester (homosalate)

in a range of biological matrices. This assay was further

applied to study the skin penetration and systemic absorption of sunscreen

filters after topical application to human volunteers. Separation was achieved

utilizing a Symmetry C(18) column with methanol-water as

the mobile phase. The assay permits analysis of the sunscreen agents in

biological fluids, including bovine serum albumin (BSA) solution, plasma and

urine, and in human epidermis. The assay was linear (r2 > 0.99)

with minimum detectable limits of 0.8 ng for oxybenzone, 0.3 ng for

octylmethoxycinnamate, and 2 ng for homosalate and octylsalicylate. The inter-

and intra-day variation for the four sunscreens was less than 3% at

the upper end of the linear range and less than 6% at the lower end. Recoveries

of sunscreens from plasma, 4% (w/v) BSA solution and epidermal membranes were

within the range of 91-104%. Recoveries from

urine of the four sunscreens, and oxybenzone with its metabolites were more than

86%. Up to approximately 1% of the applied dose of oxybenzone and its

metabolites was detected in the urine. Appreciable

amounts were also detected in the stratum corneum through tape stripping. The

HPLC assay and extraction procedures developed are sensitive, simple, rapid,

accurate and reproducible. Results from the

preliminary clinical study demonstrate significant penetration of all sunscreen

agents into the skin, and oxybenzone and metabolites across the skin.

Were these sunscreens applied at 100%. The abstract doesn't say. It's

important to remember that diffusion through a membrane is concentration

dependent. This is defined in Ficks first law of diffusion.

>yikes!

>One of the sunscreens I use even has polyacrylamide, which worries me.

Here are the sunscreens that were tested:

2-hydroxy-4-methoxybenzophenone (Benzophenone-3, Oxybenzone)

2-ethylhexyl-p-methoxycinnamate (Octinoxate)

2-ethylhexylsalicylate (octylsalicylate)

salicylic acid 3,3,5-trimethcyclohexyl ester (homosalate)

Which one has polyacrylamide?

Maurice

--------------------------------------------------------

Maurice O. Hevey

Convergent Cosmetics, Inc.

http://www.ConvergentCosmetics.com

-------------------------------------------------------

[Guest guest]

I agree, it is important to get your antioxidants

through your diet, and L'Oreal's

published studies on topical

ascorbic acid application have shown

that topical AA has a lesser

effect [in terms of collagen synthesis, etc.]

when one's diet is rich in Vit C. But nevertheless,

topical delivery of antioxidants is

very effective.

>

> ti P, Ruocco E, Wolf R, Ruocco V. Related Articles, Links

> Percutaneous absorption and delivery systems.

> Clin Dermatol. 2001 Jul-Aug;19(4):489-501. Review. No abstract

available.

> PMID: 11535394

>

> You must have a copy of this issue of Clinics in dermatology. This

particular issue looks

like it was devoted to cosmetics.

Thanks to my school, I have an online subscription to

many electronic journals. I just looked at the whole

issue, and yes, it is devoted to cosmetic dermatology.

It looks like fun reading. I had previously read Clin Dermatol.

2001 Jul-Aug;19(4):387-92.

Dry skin and moisturizers.

This article also mentions that

" Lipids applied externally to the skin

can penetrate the epithelium and modify

the normally synthesized lipids in the skin. "

and reproducible. Results from the

> preliminary clinical study demonstrate significant penetration of

all sunscreen agents

into the skin, and oxybenzone and metabolites across the skin.

>

> Were these sunscreens applied at 100%. The abstract doesn't say.

It's important to

remember that diffusion through a membrane is concentration

dependent. This is defined

in Ficks first law of diffusion.

No, a commercial Coppertone sunscreen was used.

" A commercially available sunscreen product, Coppertone

Colorblok for kids (SPF 30) was applied at a dose of 2 mg/cm2

to the arms and back of three female human volunteers, aged

22–42 years. This constituted an application of approximately

1.7 g of the sunscreen formulation applied to a total area of

approximately 860 cm2. This lotion contains 8% HS, 7.5% OMC,

6% OX, and 5% OS as active ingredients. Baseline blood and urine

samples were collected prior to sunscreen application. Permeation

of sunscreen into the skin, systemic absorption and urinary

elimination

were monitored for up to 48 h following application. "

Conclusion:

" Systemic absorption of oxybenzone was confirmed through detection

of oxybenzone in the blood/plasma and in the urine. The plasma was

only measured for the four sunscreens, excluding their metabolites.

Small amounts of oxybenzone (<130 ng/ml) were observed in the

plasma, whereas other sunscreens were below the limits of

detection. Up to approximately 1% of the applied dose of oxybenzone

and its metabolites were detected in the urine (Fig. 4). The major

metabolite was 2,4-dihydroxybenzophenone (DHB), whereas 2,3,4-

trihydroxybenzophenone (THB) was detected only in trace amounts.

The low levels of oxybenzone in the blood may be due to rapid

metabolism and distribution, as has been demonstrated previously in

rats [22]. Okereke et al. further reported that oxybenzone and its

metabolites were found in liver, kidney, spleen, heart and even

testes.

Since the area of application of sunscreen in our study was

approximately

864 cm2, which is almost half the area that one could apply in

beach

sunbathing situation, the total amount of systemic absorption of

oxybenzone could be higher in practice. In addition, tissue and

systemic levels of sunscreens may be greater in young children who

have less well-developed processes of elimination, and a larger

surface area per body weight ratio than adults. Sunscreens are

recommended to be applied frequently throughout the day, therefore

the amount used in practice is likely to exceed the application

amount

of 2 mg/cm2, also promoting penetration. "

> Which one has polyacrylamide?

I only mentioned polyacrylamide because the sunscreen that I use,

Ducray Photoscreen 30, has polyacrylamide, though I think that

I will now use Bioderma sunscreens as they provide better UVA

protection, and do not use polyacrylamide.

[Guest guest]

> I only mentioned polyacrylamide because the sunscreen that I use,

> Ducray Photoscreen 30, has polyacrylamide, though I think that

> I will now use Bioderma sunscreens as they provide better UVA

> protection, and do not use polyacrylamide.

Beethovengirl,

I looked up Bioderma and it is from France. Where are you located to

get this product?

I read the Bioderma Product Philosophy and it grabbed my attention.

http://www.health-secrets.com/bioderma_productphilosophy.html

Can you get that in the U.S.?

Thanks in advance!

R. Ard

http://groups.yahoo.com/group/HLBTalk/

http://www.foreveraftersoaps.com/store

[Guest guest]

> > I only mentioned polyacrylamide because the sunscreen that I use,

> > Ducray Photoscreen 30, has polyacrylamide, though I think that

> > I will now use Bioderma sunscreens as they provide better UVA

> > protection, and do not use polyacrylamide.

>

> Beethovengirl,

>

> I looked up Bioderma and it is from France. Where are you located

to

> get this product?

I live in the US but I obtain my European sunscreens from friends

vacationing in Europe. They are sold on eBay. I know that the

seller punkydragonball is reliable.

>

> I read the Bioderma Product Philosophy and it grabbed my attention.

>

> http://www.health-secrets.com/bioderma_productphilosophy.html

I think that this is a different Bioderma because that doesn't sound

like the product philosophy of the Bioderma I use, which has

plenty of synthetic ingredients, some of which are even systemically

absorbed and estrogenic, like 4-MBC.

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?

cmd=Retrieve & db=pubmed & dopt=Abstract & list_uids=15191542

Why I'm not worried:

http://europa.eu.int/comm/health/ph_risk/committees/sccp/docshtml/

sccp_out145_en.htm

I'd like to note that some of the things on this website do not

make sense to me:

" THE PRODUCTS ARE ALSO VERY OXYGENATING....

NEUTRALIZE FREE RADICALS (O+) CAUSED BY UV, POLLUTION, SMOKING, ETC. "

Seems like a contradiction to me. Also oxygen free radicals have

a negative charge.

Here is the website of the Bioderma that I use:

http://www.bioderma.com/english/produits/programmes.asp

sorry to disappoint.