[Pharma]

Regarding calculations: THIS might help .

[Pharma]

@chemicalmatt Wasn’t intended as an offence .

Sure, as a guideline it’s okay, as good as the notion ‘w/o emulsifier’ or ‘detergent’. But you can as well just look at the molecule and tell that much.

And yea you’re right, PEGs are still in full bloom… let’s call it then the predominant hype or something in that direction?

The problem with measuring HLB by PIT technique is that many non-PEG emulsifiers lack a cloud point and calculating is more an estimation due to polyglyceryl esters being non-linear unlike their PEG counterparts.

[Pharma]

You can use whatever form of EDTA you like because, once you adjusted pH, they will all become the same.

The optimal pH for urea is 6.2. In theory, you’d need a buffer which has a pKa between 5.2 and 7.2. Upon degradation, urea tends to increase pH which means a buffer with a pKa of 5.2 will not work. Therefore you’re limited to buffers in the range of pKa ~6 to ~7.2. Notably, you’d need quite a bit of buffer… use something well tolerated. Good’s buffers can come in handy.

One trick which can work (I guess mostly if combined with a buffer) is triethyl citrate or triacetin. These will hydrolyse if pH rises and thereby release acids which lower pH back.

[Pharma]

Dimethicone doesn’t have a HLB, it has a required HLB for w/si and a different one for si/w. In addition to that, dimethicone isn’t one defined chemical molecule but can differ in length and even branching and that greatly affects rHLB. Both values could hence be true or false .

[Pharma]

Depends… see, GSC becomes slightly anionic at pH above a certain value (I don’t know the exact numbers to calculate it) which imparts improved stability in droplet-based (aka standard or traditional) emulsions. If used as co-emulsifier in lamellar networks, it’s pH independent (too low will kill the emulsion anyway and too high will lead to hydrolysis of GSC but also 202).

In your case I’d say that you rely somewhat on the anionic nature; given that GSC doesn’t have an on-off switch but gradually becomes neutral at lower pH, it seems unlikely that dropping pH by 0.5 will neutralise the whole effect (as an educated guess, your worst case scenario would be that you have to add a bit more GSC to compensate electrostatic losses).

[Pharma]

HLB is utterly useless outside a narrow range of surfactant systems using PEG-derivatives.

Some suppliers do publish HLB-ranges for polyglyceryl esters and the like but only because cosmetic formulators are extremely stubborn (or stupid) and can’t let go of the HLB system. True, I also had to learn HLB during my studies but that was in a time where PEG-derivatives were in full bloom.

The problem is raw material manufacturers do not share (or do not know) other, more useful parameters such as those used for HLD calculations.

[Pharma]

You usually need less emulsifier than you the amount of inner phase.

Maybe try PGPR (combined with a co-emulsifier), Cetyl PEG/PPG-10/1 Dimethicone, or Isolan GPS? I don’t think you’re going to be too happy with sorbitan laurate as sole emulsifier. However, according to THIS publication, an emulsifier system of Tween 80/Span 20 might actually work…

BTW, your emulsion might turn out to be opaque or even transparent .

What is CCTG?

[Pharma]

That depends on the definition of soap.

Traditional soaps are alkali salts of fatty acids.

[Pharma]

SkinChakra has it in stock and might ship to the USA.

All other EU vendors I checked out, either don’t sell it or don’t ship to the States… Notably, shipping costs can be (were they to offer it one day) over $ 100.

Unfortunately (for you), I don’t have to place an order any time soon…

Maybe you can find glyceryl caprate or glyceryl laurate? They’re not as effective and, especially GML, show some affinity for lamellar structures and ‘co-surfactancy’ in the range of fatty alcohols or the related glyceryl palmitate and stearate.

[Pharma]

Hmmm… Do antioxidants, chelates, and boosters also count as part of the preservative system or are we talking traditional preservatives?

As an imaginary employee of ACME (A Cosmetic Multibillion Enterprise), I would propose benzisothiazolinone. Maybe add some other stuff such as chlorphenesin, just to be on the safe side .

Me as me, I wouldn’t touch that stuff, just to be clear!

[Pharma]

Too much oil in water emulsifiers especially for a glycerol in oil formulation.

You could try a pure d-phase (sucrose stearate and laurate are your friends) or a HIPE.

High polyol content in your water phase (or pure glycerol instead of water) will shift the apparent hydrophilicity/lipophilicity balance or difference meaning you can’t use HLB and you’re likely lacking the necessary values for HLD. This may be the reason why your surfactants work against all odds.

Replacing paraffin with a short polar and/or branched-chain oil might also help to reduce the amount of required surfactant and further lowers apparent HLB (increases chances for plyol/o over o/polyol emulsion).

[Pharma]

Most publications I’ve come across were either old, used just the 4-5 most common lab microbes, included irrelevant preservatives, used irrelevant/ridiculous formulations, or were sponsored by cosmetic industry (usually the producer of the ‘winning horse’).

Besides that, such studies are quite often utterly useless in practical everyday life unless you use exactly the one formulation of the publication.

Maybe focus more on the different spectra (gram+, gram-, yeast, fungi) and modes of action (if known) of single preservatives. Also take into account if they are pH dependent, inactivated by certain ingredients, volatile (headspace preservation), interfere with emulsions, act as ‘…static’, ‘…cide’, or booster, logP and surfactancy, species of current contamination, and so on… These things alone may not suffice but can give you a good head start when choosing a new or tweaking a current preservative system.

[Pharma]

Why do yo add maltodextrin? What’s it supposed to do?

It’s bug food but not a too bad one given that it’s a pure carbohydrate and hence about as easily eaten by microbes as a lot of other ingredients. It provides the same elements (C, O, and H) as for example gelling agents or oils and this isn’t sufficient to guarantee growth, like a car requiring more than gasoline to run. Only if you combine it with ingredients rich in nitrogen, phosphorous, and trace elements will it become a ticking microbe bomb.

[Pharma]

Zinc oxide, depending on quality, can serve as catalyst for different types of chemical reactions such as oxidation also of oils.

However, blue is often an optical illusions. Not saying that said illusion is ‘harmless’, it can indeed be caused by degradation but it could also be happenstance.

I don’t think it’s contamination (microbes) after such a short time.

[Pharma]

Better use potassium sorbate, not sodium benzoate against mould/yeast.

With one to three months shelf-life, sufficient preservation shouldn’t be too difficult to achieve.

If you can’t/won’t run challenge tests, combine your current preservative system with a benzoate/sorbate combo (or anisate/levulinate) and, very important, EDTA or another chelate (eco-friendly GLDA or natural phytate) and you should be more than fine.

Apart from that, 2% oil in 8% surfactants… does it even clean? I mean, if you’re trying to be eco-friendly, omit the oils and maltodextrin (use these as leave-in conditioner) and reduce the amount of surfactants (this also means less bug food and hence easier preservation) .

[Pharma]

It is a trendy osmolyte and compatible solute. It is mainly found in bacteria whilst plants and animals use other compounds for similar tasks. Apart from cosmetics and other dermal products, several pharmaceutical products containing ectoin as active ingredient like nose sprays, eye drops, or lozenges have been popping up in the last few years. These feel ‘comfortable’ but the effect ain’t as good and strong as I expected from marketing claims. Ectoin may have some advantages over other osmolytes such as being less tacky, having a faint anti-allergic and anti-inflammatory activity, and if applied as hypertonic solution won’t sing as unpleasant as salt and even glycerol do.

Maybe one reason for its fame is that it protects from higher heat, pressure, and salinity than other osmolytes and compatible solutes and is hence called an ‘extremolyte’… which is maybe less due to its chemistry rather than the fact that plants and animals couldn’t live under those extreme conditions no matter what even if they were to use ectoin instead of glycerol, glycine betaine, erithritol, taurine, trehalose, proline, or similar compounds.

In my personal opinion, its’ more smoke than fire. Given the high price, my interest in ectoin has faded…

[Pharma]

Reduce the amount of polyols… the result will ‘dry’ faster but the serum will be less hydrating.

Add silica or similar to increase surface (faster evaporation) and impart a drier, powdery feeling or replace some water with volatile liquids.

More Siligel may turn it even tackier and slower to seep in. Try it out.

[Pharma]

Benz3ne said:

…‘if the body recognises the structure as a barrier for skin, does it afford less time/resource to rebuilding a (possibly) non-existent barrier’. This does go somewhat against the evidence you mention regarding wound healing only if there is stratum corneum present, but this could be sufficient for addressing small wounds, perhaps?
I think we’re also deviating from the original question when going deeper into which more common/researched drug delivery methods are viable versus a hypothesis of a drug-containing lamellar structure being viable. The ‘would it help wound healing?’ question doesn’t really go into deep/extensive/muscular vs surface wounds vs burns type questions, but is a very broad question.
Xanthan and carbomer do have the potential to aid delivery though, right? If the thickening agent is also film forming then there’s scope for prolonged delivery of actives, or reactivation in contact with water, or similar. In these cases there potential for assistance from an otherwise benign ingredient.
…
All-in-all, I’m enjoying this discussion! 

I’d say, if it mimics/replaces a building block of our body, it takes less time/resources for the body to heal simply because you provide the template. Like a synthetic skin or bone graft. Depending on the tissue you want to replace, different matrices are used. Check out the latest in wound healing and skin replacement products, so called ‘epithelial edge advancement’. These may contain living cells from humans and/or animals and be single or multi-layered and hence replace dermis and/or epidermis.

Common creams do not penetrate deep, though they may serve as depot, carrier, and penetration enhancer for actives. This means that a cream can, with a few exceptions, only replace/complement material between keratinocytes. In case of ceramides, they only work with living cells still present and they do work by replacing what’s lacking. This ‘fast healing’ allows skin to regrow normally and healthy, the effect is sustained, skin is healed. This is not the case with liquid paraffin or petroleum jelly which does penetrate as deep and also fills out the gaps between keratinocytes leading to a replacement and ‘instant fix’ but it’s marked dissimilarity with skin lipids disturbs the natural order and the effect is only present as long as that goo is present. Sure, both may lead to healing by reducing TEWL but one is physiological and performs better. The real reason behind is unknown and may, as usual with cosmetics and cosmetics funded university research, be more of a marketing ploy or biased/forced result.

Xanthan and carbomer may have potential… as good or bad as every ingredient you can imagine… it all depends on what ingredient you plan on using in which type of product. There is no one single ingredient which does it all. If the film is too dry or the interaction film/polymer with active ingredient is stronger than the interaction of active with skin, then that film will form a depot, a depot that active will remain within until you wash it off.

Benign ingredient? Unless you manufacture cytostatic drugs, chemical weapons, or voodoo poultices I really hope you’re not using malign ingredients! LoL!

Me too! Always in for a deeper, interesting conversation, even if it’s fairly OT.

[Pharma]

Placebo isn’t a thing of belief, it’s real, proven, and scientific. 40% of pain killer activity is actually placebo effect and it is taken into account by big pharma. We know for example what causes ‘placebo’ pain relief, we can block it with certain drugs and we can provoke it in the few subjects devoid of any by administer the right drugs. What we don’t know is why on earth our body do produce placebo effects. It’s not, or rather not entirely, dependent on conciousness, memory, experience, belief, or the like because it does also exist in babies and animals. It may be to some part the ‘ritual’ (caring for a crying baby or a whining dog) which triggers it? In adults, homoeopathy doesn’t works in a clinical setting (double-blinded etc.) but in real life situations, it does. There are several reasons why, just ask a pregnant woman who’s not allowed to take anything ‘useful’ (chemical). Many would tell you that a tea, some globules or a herbal poultice work great. These probably have a pharmacological action (though weak) but they certainly help because said woman can actually do something actively against her illness/discomfort and it also helps kill time till it gets better by itself. It’s a win and if you don’t ask for the how, it ‘really’ works. Your reality isn’t what is out there, it’s what you perceive, what your brain interprets from a fraction of inputs it gets from your environment.

The world is still a mysterious place full of awe and wonder! From a scientific and psychological point of view, magick (not stage magic) is real (depending on the definition of magick, of course I’m not talking Harry Potter here 🙂 ).

[Pharma]

Perry said:

… P&G, L’Oreal, and Unilever have scientists who’s main job is to find technologies in other industries & adapt them to the cosmetic industry if possible.

…

What big corporations often do, especially in cosmetic industries but probably everywhere like automobile industry and agrochemistry, is to ‘harvest’ patents for the mere reason to be the first and only one having access to a new tech and not necessarily trying to actually use it. As long as it slows down competition, it’s already a win. For big corp with established products and production lines, new technology can be hard to adjust to and even if it actually slows down overall progress and development of the entire industry, it can be a win for a single company.

Besides, many new techs are too expensive and/or too elaborate to be of actual use in an industry such as cosmetics…

[Pharma]

You could use pure epigallocatechin gallate, the alleged main active constituent of green tea extract (neglecting caffeine). Used at 1-2% it might be closely as effective against condyloma acuminata as Veregen. This cream contains 10% extract which corresponds to about 1% EGCG.

If you’re more after the vascular effects, you could replace it with different other plant extracts rich in EGCG and other polyphenols such as pycnogenol from Pinus pinaster or something with triterpene saponins such as Butcher’s broom or horse chestnut.

[Pharma]

Benz3ne said:

…It’s more focussed on the lipid arrangement of the skin surface so helping provide a barrier which, I guess, could aid wound healing as the barrier would be ‘accounted for’.
I guess if you couple that with wound healing drugs then there’s potential to speed up wound healing further.
…

Lamellar gel networks are a type of architecture (likely abundantly) present in cosmetic formulations, they aren’t the emulsion like a micellar water is in fact micelles in water. A lamellar gel network is usually just part of a product, like bones being just a part of what holds our body together.

These lamellae may look similar to the cement and mortar between keratinocytes but most have noting to do with it and will not interact with it other than petroleum jelly does. If you want to mimic these skin structures, you need similar constituents e.g. a mixture of ceramides/fatty acids/cholesterol or other synthetic/plant based analogues thereof. There’s scientific evidence showing that such products speeds up would healing but only if there is stratum corneum present (simply because these lamellar structures are only part of the SC, not deeper skin layers).

Different types of formulations can help with drug delivery, AFAIK lamellar gel networks are commonly not regarded as such simply because they aren’t a vehicle like micelles nor do they show any advantage or depot effect like microemulsions or solid lipid nanoparticles and what not. If you were to investigate pharmaceutical creams you’d likely find out that quite a few of these actually contain such lamellar gel structures but nobody ever cared. You can’t package/load a drug into a lamellar gel structure like you can into liposomes. It’s just a 3D network spanning throughout a cream like xanthan or carbomer to thicken the water phase.

BTW I’m well aware of the study you cited: It’s one of those basic
research investigations right now completely useless for end users. It
may help understanding and planning the future but right now, only a
fool would create an oil-free cream using only water, SDS and cetyl-
and/or stearyl alcohol. Add oil or an active and the whole system tilts
towards an unpredictable state.

[Pharma]

zetein said:

…

Is this article on the same thing?

…

And it makes me wonder… Wouldn’t the ancient stearic/stearate self-thickened vanishing cream have the same “tech”? Would you say suppliers selling “liquid crystal” emulsifiers are scamming like what were made about “micellar cleanser”?

Or are there truely something special about them?

This article is exactly about that. However, we’ve came a long way in the last 30 years since that publication. Not that we always learned new things rather than start to understand the old, often neglected, insights better and sometimes seemingly arbitrary and freak discoveries turn out to be the norm.

It’s not a ‘tech’, it’s simply a type of emulsion which is neglected by many (small scale producers and scientists in particular) but becomes increasingly prominent mostly due to its flexibility, ease of manufacturing, stability, independence of HLB… it’s by no means scamming. It’s not better or newer, it’s simply a type of emulsion often neglected in the past because of poor scientific interest (it’s not those neat round spheres where you can do maths with) and even poorer predictability (and on the other hand the no-need to predict too!). It’s maybe THE form for emulsions on a practical scale because it’s a mixture of droplets/spheres, pools of liquids, and those crystal-like ‘sheets/lamellae’ composed of an often undefined mixture of surfactants, co-surfactants and lipids (and likely hydrophilics such as glycols). With growing scientific background, the need for new things (on the seller and buyer sides!), pseudo-scientific interest of consumers and producers, and likely other factors including green/clean ingredients, and the death of HLB (yes, HLB is dead, cosmetics producers just haven’t accepted that they’ve been riding a dead horse for decades whilst, I’m quite positive, raw ingredient manufacturers knew it for a long time) made this type of emulsion/emulsifier system a real thing, a thing which can be sold/bought. This system may, like everything else in cosmetics, be sold as ‘science’ and ‘better’ and ‘eternal youth’ as is done with micellar water… but honestly, it’s more valuable and way more prevalent than that. BTW micellar water would be an archetypical o/w emulsion variety taught at universities because it follows the rules and is pseudo-predictable (at least explainable/calculable in hindsight). Lamellar systems don’t and aren’t and that’s why they were treated like orphans though they are probably/likely the predominant emulsion type consumers use these days. Sure, those droplet type emulsions are still very frequent simply because they are usually part of a lamellar gel network emulsion . Apart from lotions and heavily gelled creams, you’ll have a hard time finding products which do not, to some degree, contain lamellar structures. As a side-note, they’re not always visible as maltese crosses but may diffract polarised light in different ways and, for a layman, aren’t necessarily distinguishable from ‘solid fat content’ (= fat needles/platelets and the like which also diffract polarised light -> true vanishing creams are extremely rich in these and will likely mask lamellar structures under a light microscope!).

So, I don’t know if vanishing creams contain lamellar gel networks though it’s well possible. They pre-date current knowledge and are now outdated and hence no longer of any scientific interest. You’d have to ask a cosmetic archaeologist 🙂 .

[Pharma]

Ascorbic acid is a stronger antioxidant than tocopherol and other phenolics. If you want to protect these, go with ascorbic acid for water soluble compounds or ascorbyl palmitate for oil soluble ones. You can’t use tocopherol to protect an equally good or even better antioxidant.

Obviously, a good antioxidant reduces things and thereby gets oxidised. It does so when there is oxygen or other oxidising stuff around, that’s its job and the one reason why you add an antioxidant besides for skin benefits. Tocopherol does the same, it’s just not as easily visible and doesn’t react with oxygen as easily . The higher stability of tocopherol seems nice at first glance until you realise that it’s oxygen which messes with your colour and the green tea constituents…

As a side note: Tetrahexyldecyl ascorbate is not an antioxidant, it’s a precursor which is supposed to turn into one once assimilated by skin. It’s not supposed to do anything in and with a product but only with skin cells.

[Pharma]

The issue is not a ‘stable’ formulation with regard to physical stability but microbial stability .

If you want to play on the safer side, use ‘solvents’ such as glycols in your water phase to force phenoxyethanol out of the interface (i.e. the PEG-shell around the emulsion droplets). This however is not an exact science and glycols also tend to sit around the interphase… only a challenge test will tell if you’re on the right or wrong track.