I'm trying to make a clear Parodinal using paracetamol tablets, and mixing it with ethanol to separate the binders. Does the paracetamol crystals from this method keep well? Or should I make only small batch.
My scale broke and haven't got the chance to buy a new one, thats why I can't make the parodinal right now.
.
(2) Add 80 500 mg tablets to the methanol and seal the jar. No crushing is required. Just drop them in, then shake the jar every few minutes. In about two hours the paracetamol will have separated completely from the binder. This puts about 40 grams into the 400 ml solution.
(3) Set the mixture aside for about 3-4 days. Leave it completely untouched so that gravity can do its work. The solids will completely settle out leaving a near crystal clear liquid. If you want true crystal clear, wait about a week. This is my workaround for not owning a vaccum filter flask or centrifuge. If I was going to do this on a regular basis, I'd invest in a flask and hand-pump or aspirator.
(4) Since the Parodinal formula calls for 30 mg of paracetamol for 500 ml of developer, I next use a 60 ml syringe (intended for livestock, not humans, so it's easy to source) to carefully remove 300 ml of clear solution from the jar. This is why I need 400 ml to start. The residual solids fit comfortably into that remaining 100 ml at the bottom and don't contaminate the 300 ml I've removed. 300 ml contains 30 mg of paracetamol. No scale is thus required.
It has been a while since I used my chemistry degree, but I wonder if you have a mistake here between step 2 and 4 (or you may know something that I don't). If you have 40 grams of paracetamol in your solution in step 2, and 30 milligrams of paracetamol in 75% of your solution in step 4, where did 39.970 grams of paracetamol go?
In para (4) where it twice says 30mg Paracetamol it is a typo, it should be 30g Paracetamol for 500ml developer.
http://www.digitaltruth.com/data/parodinal.php
I make clear Parodinal from the type of capsules whose contents can be tipped out and weighed.I also use half the amount of sodium sulfite given in the above formula.
The N substituted aminophenols are far less sensitive to oxidation than the parent chemical paraminophenol. This is why Metol and Glycin are used as developers. First isolating the acetyl paraminophenol by dissolving it in alcohol represents an unnecessary step.
And to the OP's original question, what would be your opinion regarding the keeping properties of paracetamol that has been separated from the tablet binders, even if that isolation step may not be absolutely necessary?
Thanks and Please share the result Ken
I would say that the keeping properties would be excellent.
As to the frothing, different brands may use different fillers. Some brands may not produce frothing.
Yikes! Not exactly sure what I ended up with tonight. Won't even know if it's a developer for another 72 hours. But I gotta tell ya', it's absolutely gorgeous to look at in a clear bottle...
Steps 1-4 went exactly as planned.
In Step 5 I skipped the waterbath and precision temperature control and just set the beaker with a suspended thermometer on the hot plate and manually adjusted things to 50C/122F. I used a stir bar until evaporation reached 100ml of solution remaining. Then I removed the bar, turned the temperature down and let the final crystallization take place.
In Step 6 the water went in at 10C/50F.
Step 7 caused the crystalized paracetamol to mostly dissolve, but again there was residual frothing. Not nearly as bad as before without the binder separation, but still some present. Highest temperature reached was 27C/81F.
In Step 8 I neglected to adjust the temperature up to 52C/125F before adding the sodium sulfite. It took the 50g quite a while to completely dissolve. I turned up the hot plate until the solution reached 52C/125F to help things along. Eventually it all dissolved. At this point the solution was a light pinkish-tan color, transparent, but with froth floating on the top and more suspended within, giving it a cloudy look. There were no undissolved crystals of any kind on the bottom.
For Step 9 I decided to filter the solution into a graduate, then top it off to 500ml. I reached for my usual brown-colored coffee filters. Unfortunately, I don't think I've ever before used those to filter a solution containing 80g/liter of sodium hyroxide. So as my pinkish-tan color went in the top, an absolutely beautiful amber-brown color emerged from the bottom, thankfully minus any of the froth.
But damn. It looks for all the world like Jack Daniels Old No. 7 Brand Tennessee Sour Mash Whiskey...
:eek:
Leached the color right out of the filters, so at this point I have no idea if this new variable has ruined everything. And I'm certainly not going to be able to judge any subtle color changes with age. All I know is it was pinkish-tan to begin with.
Does anyone know what's in those natural brown coffee filters that give them their color? Just my luck it will probably be a huge restrainer. Guess I need to invest next time in some real filters.
Well, even if this stuff can't develop a single frame of exposed film, it will still be a damned impressive looking, crystal clear shelf queen. Only time will tell.
Ken
The one and only time I made clear Parodinal, about 6 years ago, I evaporated the alcohol from the solution by pouring it in a wide shallow tray. Then I propped up an electric hair dryer a short distance from the tray and turned it on the low setting. I adjusted the hair dryer so the air was blowing on the tray of solution at a shallow angle and far enough away to not agitate the solution too much or splash any of it out of the tray. I could see little ripples in the surface of the solution as the warm air moved across it. About two hours later, all the alcohol was evaporated. I did this in the garage with the main door and side door open for ventilation, and made sure no other electrical appliances were running.
Tylenol and generics contain N-acetyl paraminophenol and fillers to allow the ingredients to be made into pills. According to the US Pharmacopoeia, "fillers are chemically inert, compatible with other ingredients, water soluble, relatively cheap, colorless and tasteless." The fillers can be removed at any time before the use of the developer. Since the fillers are insoluble the easiest method is to prepare the developer and then filter the resulting solution. Since the amount of the active ingredient is stated on the label, the pills do not need to be weighed.
Jerry, you have me confused. Not difficult I admit, but the USP as quoted says the fillers are among other things, water soluble. Then you go on to say they are insoluble. Which is it?
Murray
Thanks! I guess it's kind of obvious now your forum searching skills are a lot better than my memory...Hi desertrat, my first try is actually inspired from reading your post on that thread
I'm trying to make a clear Parodinal using paracetamol tablets, and mixing it with ethanol to separate the binders. Does the paracetamol crystals from this method keep well? Or should I make only small batch.
No it doesn't keep well, you need to separate it and then get it into solution with preservative (ie: get onto making the parodinal with it).
On what do you base your assertion? As I stated earlier the N substituted paraminophenols are more stable than the parent paraminophenol. The following site http://www.pharmweb.net/pwmirror/pwy/paracetamol/pharmwebpicm.html says that a saturated water solution has a half-life of twenty years.
Hi Ken,
Thanks for the links, i'll be sure to use methanol for my next try. Yes the tablets themselves keep for a long time based on the expiry dates on the sleeves. My scale broke and haven't got the chance to buy a new one, thats why I can't make the parodinal right now.
. My test (about two weeks ago), that I keep in a sealed clear plastic bag still have the same form and color. It is slightly pinkish in color.
Although I can just mixed a new batch later, I guess I just want to know the possibility making some on a larger amount and storing them.
Dave.
And I am basing the instability of the extracted dry form on first hand data. Once you extract the compound from the solution, dry and and grind it, it will oxidise and turn burn even in jars quickly.
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