Liquid measurement w/ Visine bottle

[Jayman]

I have a small 15ml bottle of Visine that I cleaned and did some calculations with. I've determined that about 18 drops from the bottle is approximately equal to 1 ml. +or- 1 drop.

I have 100mg of DOC that I want to dissolve into a liquid of 10ml. Now if I decide to do that I will end up with each drop equal to 555ug. I have thought about decreasing the amount liquid to 5ml thus making the doses 1.111mg.I am thinking that .555ug will be kinda weak or does that sound like a solid and safe area to keep that solution at?

I wanted to mix it into a liquid so that I could possibly make some blotters but if I were to make 2mg blots, that would be 4 drops which to me seems like alot of liquid. I'm not sure if I am going to make it into blotter though, I am really just looking for the safest and most efficient way to store it for my personal use in the near future.

I have not received my .001 scale yet so I also need a way to measure my doses because I want to dose pretty soon.

Damn, I just realized i would have to add the doc to a volumetric container then add the 10 or 5 ml of water and get a new total volume, adding till nearest ml for ease, to obtain a true concentration of mg/ml .... right?

Thanks for your time.

 

[elucidator]

I advise against dropping liquid solution on blotters. It is more efficient to just drop the drops directly.

If you haven't recieved your .001 scale yet, how can you be sure you have exactly 100mg? Please be 100% sure on your amounts before doing liquid volumetric measuring, which is covered in more detail in the Big and Dandy on the subject.

http://www.bluelight.ru/vb/showthread.php?t=286239

 

[Solipsis]

You shouldn't make a solution where a drop is a dose or somewhere near it. Maybe that seems cool or it makes sense that a drop is a hit, but there are a lot of disadvantages or risks. Instead you should make weak drops, that way you can account for the fact that droplets are not consistent volumes and it will allow more control over the exact dose you want to take.

Something like 250 ug increments doesn't sound too bad to me.

Wait until you get a scale, it is irresponsible to rush it because 'you want to dose pretty soon'.

I don't quite follow your last sentence, seems like you are overcomplicating things maybe? Please explain.

 

[elucidator]

I think he just realized that he needs to account for displacement to have an accurate number of drops.
I completely agree that each drop should be weaker than 500ug, far less room for error when the substance is diluted more.

 

[Jayman]

I think he just realized that he needs to account for displacement to have an accurate number of drops.
I completely agree that each drop should be weaker than 500ug, far less room for error when the substance is diluted more.

Yeah thats what i was talking about.

I found a dark glass container that the top of it has a built in dropper with the rubber piece on it. Five completely full droppers is 1ml. ( Its very small and was used for ear medicine) I made a solution of 8ml and added the DOC. I am not going to put it on blotters. The concentration is 2.5mg per full dropper. I know it is very strong and I will be very cautious.

The only problem I see is small flakes left in the solution no matter how I shake it.

 

[Solipsis]

There is no significant displacement though, the drug is not immersed but instead dissolved in the solvent. The volume taken up is not additive, it is better to imagine the drug molecules sitting in between the 'empty' places within the solvent. There is some displacement but in most cases this is infinitisimal. With some chemicals IIRC it can even be negative because spatial molecular arrangement becomes more efficient. For example I think if you mix water and alcohol the total volume is less than the two separate volumes added up, because they dissolve in each other so to speak.

To dissolve small flakes there are a few solutions: if it is minimal you can try heating it up a bit. However if the solubility is too limiting it will crash out again when cooling back down. It is also salient to mention what solvents you are using. If you are using water, some alcohol may solve the problem. You might need to dilute your volume 2x though which might solve the problem anyway even if you are just using water. Another possibility is complexing / using a surfactant. A common well-known example of this phenomenon is soap which allows dissolution or rather emulsion of oils and fats (e.g. dirt you want cleaned off) in water which would otherwise not be possible. For your purposes there are alternative compounds to normal soaps though, that are more suited for the drug and that are consumable.

My knowledge might not be very fresh so I'd like some peer review on this, but I think this is right.

 

[sekio]

There is no significant displacement though, the drug is not immersed but instead dissolved in the solvent. The volume taken up is not additive, it is better to imagine the drug molecules sitting in between the 'empty' places within the solvent. There is some displacement but in most cases this is infinitisimal.

This is highly dependent on what you're dissolving. Trying to dissolve 80 grams of ammonium sulphate in 100ml of water will result in a solution that takes up more than 100ml. Likewise if you're dissolving 0.1 gram of a drug into 10 ml water, the final volume will be much closer to 10ml.

Depending on whether or not you have free base material, you may have to add a small amount of a food safe acid (vinegar, citric acid) to form a water soluble salt, if the compound doesn't want to dissolve.

It is also important to remember, that droppers are not reliable for accurate dosing. The inter-drop variability can be quite large.

 

[Jayman]

When i said that 5 full droppers full i meant that its the most it can possibly suck up in one squeeze and i tested that 3-4 times to get that every time i empty its full contents out that it took 5 times for it to equal exactly 1 ml.

The amount that will not dissolve is really insignificant, probably less that 1mg. The small container is pretty much full with 8 ml of water plus DOC, I am not sure i can add anything else to it so I'm not sure if its worth trying.

Also thank you all for your time contributing to my thread, Everything you have informed me I will put into practice. I am all new to this but I want to learn as much as Solipsis and Sekio and anyone who knows more than I. ^_^

 

[elucidator]

I completely agree with Sekio, the dropper on those types of small vials are unreliable for measuring solutions as strong as that. I advise to buy a small sample bottle of some strong alcohol, and dilute your solution 50/50 , giving an end product of a tiny bit over 6mg / ml.
With the investment of a small oral syringe (available in childrens panadol), this diluted solution would be far easier to accurately dose, than it would be with the dropper. Also, adding the alcohol would greatly reduce the chances of bacteria getting established in your vial.

Edit.. I checked the solubility of DOC and it shows that DOC solubility to water is very high, it saturates at levels far higher than the concentration used here (with slight applied heat).
There is a chance that the undissolved crystals in your vial may be insoluble impurities.