[Pharma]

Well… probiotics are a different story cause they are, by definition, living microbes… dunno how that should work unless dispersed in lyophilised form in an anhydrous product.

[Pharma]

Freezing EOs greatly increases their life span (~16 times based on a physicochemical rule of thumbs 🙂 ). However, scent has quite often a nonlinear correlation between amount and fragrance. Small changes can ‘spoil’ a scent even though it’s technically absolutely okay and within specs or an EO smells okay even if it’s visibly gumming. Most of the reactions happening in most EOs over time and under oxygen won’t make them toxic or dangerous, rather the opposite (many allergenic constituents tend to be the ones gumming first). Bottom line is, expiration dates of EOs is a matter of scent rather than safety.

[Pharma]

Because single living microbes can’t be counted in a product, one takes a small amount of known volume or weight and puts it on a plat at different dilutions. What then happens is that every living microbe will grow and form a visible colony, hence Colony Forming Unit. Take a plate where you can count the colonies easily; the dilution rate and the initial amount used for incubation tells you how many CFUs aka living microbes are in the product.

In pharmaceuticals, tolerable CFU depend on the product (what type and which usage) and the microbe (environmental germs, facultative pathogens, or pathogens such as faecal bacteria like E. coli and toxin producing microbes such as Aspergillus sp.). The tolerated CFU/g or /ml in pharmaceuticals are listed in pharmacopoeias.

[Pharma]

Cosmetics… when people pay hundreds of $$$ for bug poop :smiley: !

[Pharma]

Do you know Estée Lauder’s Advanced Night Repair Serum?

It’s one of the first well known products containing ferments which are now hyped as ‘postbiotics’… I guess that back in the day when they launched it, this term hasn’t even been invented yet .

[Pharma]

He’s referring to triethyl citrate. It’s not an acid but a tripple ester of citric acid with ethanol. Once pH increases, it hydrolyses turning into citric acid. This in turn brings the pH back down (and also stopps hydrolysis).

w/o emulsions also have a pH which can (and will) drift when using enough urea. Unfortunately, there is no benefit from using this type of emulsion when it comes to stabilising urea. I tried making w/o emulsions with 40% urea… was fun but didn’t work out (emulsion instability, not chemical instability). Urea is the same b*+ç# as always and heavily interferes with HLB/HLD calculations/estimations and oil phase integrity/stability.

[Pharma]

Ahh, now I see! You want to incorporate something into the liposomes and not just create liposomes. You just stepped on the level marked with a big blinking sign reading “LEVEL 10: EXPERT” .

There is no easy method for creating those, not if you can’t determine inclusion (and losses of not incorporated actives, too) and leakage rates. Reliable… sure, if you buy a machine from a reliable company. However, chances are that you’d be better (cheaper and faster) off simply buying those loaded liposomes from a reliable source.

[Pharma]

If you hit a precise 1:1 molar ratio, pH would be neutral. Because one usually does not, pH can be higher or lower due to a small excess of acid or base.

NaOH is hygroscopic, thoug in theory 100% pure, it tends to abstract water out of air and ‘gets diluted’ over time.

[Pharma]

At a pH of 3, nearly 50% of the salicylic acid is converted back to it’s free acid form… on one hand, you could just use half the amount of sodium hydroxide to achieve the same, on the other hand does it mean that you can, with luck, solublise 0.25% total salicylic acid at room temperature (equaling 1.25 g of free salicylic acid per litre… in other words, you can’t solubilise 2% SA in water at pH 3).

Depending on manufacturing process and ingredients, it is sometimes (very unreliable and often non-replicable) possible to create supersaturated solutions which eventually crystallise out after some time (hours to months).

[Pharma]

1-5 kg lipid weight? That’s not small scale .

You likely can’t use dry film and you’re going to struggle with the solvent dilution unless you have the right equipment. Go with extrusion and buy a machine.

[Pharma]

Yes, it does. This results in 0.56 g sodium hydroxide for 2 g salicylic acid.

[Pharma]

‘New’ methods are mostly for industrial production.

What do you define as small batch?

For personal use, you could either go with the solvent dispersion method by slowly adding an alcoholic lecithin solution into water or use the thin dry film technique (preferably employing ultrasound during hydration); for more detailed information see HERE.

Another strategy are mini-extruders: CLICK

Yet another option are non-lecithin liposomes… not sure if they offer that many benefits.

[Pharma]

Simply reading this abstract may sound nice and promising in the ears (or rather eyes 🙂 ) of the uneducated.

I’m sceptical because A: never trust an abstract & read the full text, B: acetyl zingerone goes by the trade name Synoxyl AZ which is manufactured by Syntheon… who funded the publication, and C: I can spot several issues when quickly scrolling through the publication.

[Pharma]

Maybe it’s the Katon CG in it??? *Shudder!*

Silver salts are notorious for turning brown/black with sunlight (either before or after application). In an armpit, even if it did so, it shouldn’t bother anyone unless you’re jobbing also as pinup model down at the beaches :smiley: .

Silver salts are also inactivated by a bunch of ingredients (proteins/peptides, many extracts, thiols, and ascorbic acid). Hence, its limited use. Silver (foremost colloidal silver) is a bit en vogue due to it ‘being a natural antibiotic’… lots of stupid stuff is being done with it though fortunately, silver is often precipitated and thereby rendered inactive before entering the body. If you look online (on the sites where the stupid people and those who worship stupid peoples oppinions post their claims to eternal health), you’ll find for example folks using silver to preserve their dogs water bowl so they would only have to change it once every week and others drink it against a bunch of diseases. Diarrhea might be one of the few cases where silver actually helps fighting disease causing microbes by killing bacteria… the bad alongside the good (I can’t see much of a difference to using antibiotics for the very same purpose but who am I to judge LoL). On a more scientifically founded bases (however, Cochrain rates most studies insufficient), silver preparations are used for wound treatment and regaining terrain in the wound dressing sector these last few years. The two creams dominating Swiss skin burn market actually contain an antibiotic-silver complex (invented well over 50 years ago).

[Pharma]

If it’s for personal use only, then you may use EDTA and phytate longer, considerably longer. However, excess stock you’re not going to use for a while is best kept in the fridge or even freezer.

BHT is an antioxidant and tends to degrade over time tuning from colourless and transparent to a deep yellow and later orange/red/brown. Best to not use it even if a small percentage of oxidised BHT suffices to turn it visibly yellow.

[Pharma]

No, at least I’m not.

Take for example salt (NaCl), it is a poor humectant but greatly reduces water activity. Same goes for sugar (which would contain hydroxyl groups but this is irrelevant).

Deliquescent substances (mostly salts) bind water very well but they are rather poor humectants, hence their frequent use as desiccants. Humectancy is only partially correlated with water binding or water affinity. A humectant also needs to let the water go under physiological conditions. This has nothing in common with water activity. Sure, substances which do not alter water affinity will not be suitable as humectants simply because they do not interact with water (= water is the only common denominator).

[Pharma]

Gelling is not equal to reducing water activity .

Ethanol works well too but I wouldn’t call it a humectant.

[Pharma]

Depends on your formulation.

[Pharma]

I don’t think that you would buy the books I have because most of what they cover is overkill unless you study pharmacy… there are many books explaining zeta potential. Even Wikipedia might help .

Yes, lower pKa means more anionic emulsifier is actually anionic (= dissociated) at a given pH. Sulfates like SLS are kind of an exception because of the very low pKa which renders them 100% anionic under all ‘normal’ conditions. SLES has a similarly low pKa. SSL and GMS citrate are not chemically well defined. It is safe to assume that SSL has a similar pKa than lactic acid and GMS citrate the lower two pKa values of citric acid. However, GMS citrate is not used as salt but in undissocitated form and might not deprotonate as much as would be expected. Some suppliers even list their GMS citrate - fatty alcohol blends as nonionic emulsifiers.

[Pharma]

You’re asking the wrong question .

A. Surfactant charge can increase emulsion stability but usually, it’s the charge of the interface (called zeta potential) which has a tremendous effect on emulsion stability.

B. Zeta potential can be influenced by many factors. Read a book.

C. Influencing a charge of an anionic emulsifier/surfactant is basic chemistry. It boils down to pH and pKa. What does affect pH? Acids and bases. Does that directly translate to emulsion stability? No, it does not but it can.

The efficacy of an anionic emulsifier doesn’t solely depend on pH. Some anionic emulsifiers like SLL may work differently at a pH of 4 than they would at a pH of 6. Whether or not this is affecting emulsion stability depends on the whole system.

[Pharma]

The incompatibility of parabens has something to do with overall structure (especially the aromatic part) and is a thing of observation because there is no clear scientific explanation why and how.

Ionic interactions like benzoate with cationic emulsifiers clearly depend on the charge.

[Pharma]

Half the ingredients shown are at 0%….

Why do you add NaCl?

[Pharma]

None to partially negative, depends .

Incompatibility has nothing to do with ‘ionic charge’.

[Pharma]

Naw, the structure determines how strong an acid is (the value used is the pKa). However, if a molecule carries more than one acid functionality, each additional one has a lower strenght. Citric and phosphoric acid with three acid groups each has three different pKa values for ‘pronon’. This is due to an increased charge once the first functional group is deprotonated, the created negative charge reduces the acidity of the other remaining ones and so on.

[Pharma]

No, the carboxylic group is the acid part of the molecule . Meaning that one molecule citric acid carries three a acids = more acid per mol and more acid per gram. It doesn’t make it a stronger acid… quite the opposite: the second acid is fairly weak and the third very weak (due to increasing charge).