Pharma
Forum Replies Created
-
Emulsifying wax NF per se shouldn’t be too much of a problem since it’s non-ionic but the fairly small quantity of true surfactant in the mixture (Polysorbate 60) is low and it’s just one single surfactant; hence it’s prone to ‘surface charge neutralisation’ by MgSO4. I suppose you should be able to find a work-around probably by adding a co-emulsifier. Maybe try a sorbitan ester and some fatty alcohol?
-
Speed of action and depth/quantity of skin penetration depends on where you apply your product and which kind of product (gel, o/w, w/o, ointment) you use. Your first consideration shouldn’t be to try things out but to determine which galenic form fist your demands best.
-
You could try letting the oil phase ‘ripen’ for a day or two. This time is sometimes required for full gelling. Add the powders once it’s ‘solid’. Sedimentation might be quicker than gelling if you add powders in the beginning.
-
What do you mean by “the oil seeps out of solution”? Do you mean the paste is ‘sweating’ oil? What’s the melting point of your product or rather, is it only a paste with the suspended ingredients or does the oil phase harden at room temp?
-
ngarayeva001 said:…I was already scared that these environmental groups will try to ban Aristoflex soon…
They’re certainly conspiring already, working on their evil plan to ban EVERYTHING thy don’t like and which is not 100% pure, immaculate, sustainable, fair-trade, vegan, and so on!
-
Either you use an oil-base for benzocaine, benzocaine hydrochloride for a water-based product, or use either of which in the opposite way to obtain a paste/suspension in which case you may be able to reduce grittiness by passing it through a three roll mill. Which product you choose depends on the intended use.
-
If blue is water in the latest picture and yellow is water in the first picture then it means they’re both the same and water is in the middle… I guess silicone is on the bottom.
-
Maybe it’s a generation problem? As a kiddo, I used to sweat and gasp for air while pedalling cross country with my mountain bike… today, people, easy-peasy, bolt past me uphill on their e-bikes. Not saying e-bikes are bad but they are like cheating. Got it @em88 ?@Cst4Ms4Tmps4 :smiley: You’ve got it!
-
What colour is what?Give it some time, the ‘cut’ will become sharp after some time.
-
Two hours? Okay, that’s faster than I thought! Still, IMHO not practical.Also, gluconolactone is in equilibrium with glucuronic acid. Should glucuronic acid get ‘used up’ (neutralised), new one will form. That’s nice in case of an additive but complicates things with regard to maintaining a certain pH. Since we’re talking fancy/expensive acids, why not use gluconic acid or the like?
-
Yes, true, but hydrolysis is slow and it’s hence not useful for lowering pH to a given value. It will gradually lower pH during storage.
-
Gluconolactone is not pH active. Gluconic acid would work.
-
Well, it does look like 4 phases
. Anyway, some silicones have a density higher than water… What kind of silicone do you use? Did you try mixing only oil and water or silicone and water to see what happens then? Do you have to use a 1:3:1 mixture? A 1:1:1 is less prone to such an effect.Coco caprate/caprylate will float on water (add water first and then slowly drop it on top) but it will readily wet and hence stick to glass and metal surfaces, adding it the other way round can therefore ‘glue’ it to the bottom. With only minor differences in density, thin but broad layers may therefore ‘switch places’. Hence, try a smaller, less broad beaker or even a cylinder = higher liquid column = better hydrostatic effect = less power for the wetting effect. Or don’t use glass but a plastic vessel with a better wetting for water and less so for silicone instead.If you’re even adding a silicone oil and shake the triple phases, silicone will cover all the glass surfaces making it even easier for the oil to stick to it and completely impossible for the water to do the same. The pearling effect can be so strong, that water is forced to search for the place with the least surface (which would be a round body or, in this case, one between two liquids rather than a hard surface and a liquid). That might also explain the fourth phase on top which looks like water since water has some affinity for air as a surface to ‘stick to’ and a small amount might therefore be held on top against all laws of gravity and density.The smaller your sample, the less important becomes density/buoyancy/sedimentation/gravity whilst effects such as wetting and surface tension become dominating. Because of surface tension, a drop of water on a lotus leaf is nearly spherical, barely touching it, though gravity dictates that it should be completely flat. Some litres water on a lotus leave will however be flat and won’t have a football like form (only the edges will be rounded) because gravity is the dominating force at that scale. -
Eh, wait a minute… I completely missed the point about CARBOMER aka poly(acrylic acid) aka poly(1-carboxyethylene). Ain’t that a real nastiness? I mean a polythingie, synthetic plastic, explosive ethylene gas, and carcinogenic acrylic acid? That’s terrible! Think about the birds and turtles who are all going to die!!!! Arrrghhhh!!!!Seriously, you could try chitosan as a base and gelling potentiator .
-
Density doesn’t lie but some phases may stick better to glass than others and the difference of surface tension can, under certain circumstances, lead to a ‘wrong’ order of the phases. This phenomenon is usually easier to observe in a separatory funnel but I’ve seen it many times in the lab with water-solvent systems especially if the apparently lowest phase is comparatively small.Another explanation might be mixed phases e.g. water containing oil and oil containing water which leads to two differently composed mixed phases where one retains a colour better than another. What is the exact composition?
-
luiscuevasii said:Im thinking in use an aparatus like dean-stark water separator, but it would be awesome that i could use phosphoric acid, have you made an experimento ussing phosphoric?A Dean Stark won’t really work with aqueous HCl solutions. You’d distil off water and HCl together .No, I have not tried phosphoric acid but theory says it will work nearly as smoothly as sulphuric acid. There are a few reasons why it’s not used, being not reactive enough ain’t one of them.Did you try ordering the final product at Perfumer’s Apprentice? Neglecting the fun part, this might be less hard on time and budget… Glassware is expensive!I don’t see why using acetic anhydride would require a hazmat suit… It has a fairly low reactivity for an acid anhydride and it boils above acetic acid. Slowly dripping it into a chilled solution of benzyl alcohol and neutralisation of eventual residues with a bit of water just before liquid-liquid separation will result in vinegar (or just add bicarbonate solution -> careful, it will bubble like crazy). Also, you can avoid heating as well as strong mineral acids and that’s already a huge advantage over acid catalysed esterification.Besides, esterification with acetic anhydride (making aspirin) is a school experiment you can do with 14-16 year olds .
-
Did you try PEG-400? It’s said to be soluble at 37% in there. CLICK
-
Bubble hight is just one measure of many and more helpful for shampoo formulations.Clarity of the solution may be another (though it is just a measure of droplet size).Stability of the emulsion is what counts. This can be seen by absence of creaming (the milky layer between water and foam) and/or excess oil sticking to the jar.‘Best’ depends on your expectations, requirements, intended use etc.Number 3 might be best because it might be able to hold the highest amount of oil even if foam is absent. ‘Foaming molecules’ aren’t necessarily suitable for interacting with oils or creating stable emulsions.
-
Regarding phytic acid: be careful because many suppliers selling phytic acid actually sell sodium phytate or calcium/magnesium phytate which won’t do the trick.I’d say that, unless your product is really acidic and/or requires higher percentages, using any organic acid such as citric, acetic, malic, lactic or whatever to lower pH to +/- neutral won’t cause sensitisation. But that’s just a guess!
-
It is possible but you have one main problem, water! Esterification only works in anhydrous systems and HCl comes at <35% aqueous solutions. Trying to remove said water by evaporation will evaporate HCl first whilst chemical or adsorption strategies (such as anhydrous Epsom salt or molsieve) will turn HCl into a gas and then you’ve got to run. You may want to try phosphoric acid or acetic anhydride
. In the latter case, you have to gently neutralise the excess acetic acid before solvent extraction or distillation. -
Nicotinamide isn’t even a good base… Why not take the aforementioned arginine or free base lysine? Unfortunately, there aren’t that many available and ‘clean’ bases available ;( .
-
The problem is that said extracts, or rather the active constituents therein, are lipophilic (i.e. fat/alcohol soluble). Fairly often (for economical and toxicological reasons) such extracts are for said reason made with ethanol (or supercritical CO2 but then cost more). Therefore, re-solubilisation is only possible with similar solvents. You may try to evaporate the solvent and reconstitute in glycerol or a glycol. Since an extract (apart from pure resveratrol) obtained by ethanol extraction contains a mixture of medium polarity compounds, the obvious and only “good” solvent is ethanol. Water will only dissolve some constituents, oils only others. Although, you may want to add your solvent of choice before evaporation (just make sure it doesn’t evaporate too!) and not to the dry, sticky mess after evaporation because for a bunch of reasons (some of which are unknown) such a dry or semi-dry (in pharmacy it’s called a spissum extract) will often no longer fully re-dissolve even in the original solvent. That’s one reason why several extracts are only sold as diluted solution. On the other hand, the ethanol % in the final product might be very small and will not really impact your product neither will a possible evaporation of that ethanol.
-
Will said:…
Is that just a super emollient combined with some strong surfactant (sulfonic acid) for skin penetration??
…That’s HEPES, it’s a so called ‘Good’s buffer’ or simply said a valuable pH buffer for in vitro assays and for culturing cells (like cancer cell lines). IMHO it’s in most cases ridiculous to add that to a cream.
-
Dr Catherine Pratt said:…What does everyone think about the e-cigarettes that are flavoured but using glycerin as the solvent?? I have friends that do this and I thought it would be very heavy to suck glycerin into your lungs? I know it is heated but I thought maybe I could find them a different solvent maybe like Propanediol ?? Any suggestions?
Get them a PAX3 and have ’em vape high quality pipe tobacco
. That’s what I do because it seems the least unhealthy option of all (less chemicals, nearly no tar, and the full kick of nicotine). See, glycerol but also propylene glycol are used more for the “smoke” (vapour) than anything else, it’s the same as disco fog. Ethanol often serves as carrier/solvent for nicotine/flavours but in its pure form ain’t nice to vape, hence mixtures of water/ethanol/glycerol are employed. The problem is that many vaporizers for liquids heat above 220°C and that’s when glycerol and glycols decompose to hazardous aldehydes! The advantage of a ‘weed’ vape is that good quality pipe tobacco (don’t try cigarette tobacco!) doesn’t contain humectants (cheaper one does and clogs the vape fairly quickly) and that the PAX3 only heats up to 215°C max. Problem solved. Well, that’s if you like pipe tobacco flavour and don’t give a darn about nearly no visible smoke/vapour and a session of 5-15 minutes. Cheaper vaporizers with a lower draw resistance work better for ‘quick hits’ but forfeit flavour quality. 1,3-Propanediol should work because its boiling point is between the lower boiling 1,2-propanediol aka propylene glycol and glycerol. Since it’s not a glycol, it may not form aldehydes… but that’s mere speculation and I honestly don’t know how healthy it is to inhale either of the propanediols. If you wonder why glycerol works with a boiling point of 290°C: It is passively drawn into air by water/ethanol vapour whereas propylene glycol boils at vaporizer temps. -
margi said:…yes i know you also need to eat and so on for your hair etc…
…any vitamins oils anything?…The most important thing is exactly what you eat. Since most vitamins (except antioxidants) are useful only for living cells and are poorly absorbed by skin, adding them to the hair instead your food is wasted money.Sure, using oils such as shea butter or fatty alcohols like cetanol makes especially dry African type hair shiny, springy and looking healthy (on the other hand, mine would look like greasy, overcooked spaghetti). Adding some of the aforementioned synthetics will further increase the effect . Depending on hair type, the ratio of absorbed ingredients (like oils, butters, and fatty alcohols) to “masking” ingredients (such as silicone derivatives, cationics/quats, and polymers) may vary.Humectants such as glycine betaine, glycerol, or amino acids may be beneficial in leave-in products.