Dissolving diazepam in propyl glycol

[[Buddie]]

When dissolving benzos in PG does it matter if the pill sits at bottom of test tube after crushing? Or has all the active ingredients dissolved into solution still?

[[Buddie]]

Its very difficult to know which ingredients of the tablet dissolve and which don't so its best to treat your liquid as a suspension and stir, shake or mix it up before ingesting it.  You also want to make sure you ingest the particles remaining in the tube by putting some additional water or PG in and drinking that as well. 

[[Buddie]]

Okay thanks for the reply much appreciated.  Bit of a long shot but I don't suppose you would also know if PG being classed as alcohol would raise CDT levels on a blood test?

[[Buddie]]

Just incase it might help somebody out if they stumble upon this post the liquid solution did work. Dissovle a 5mg Diazepam in 10ml of propylene Glycol for a couple of hours then add 40ml of water. So 10ml = 1mg of Diazepam. Has gone a lot smoother than cutting tablets.

[[Buddie]]

Note that in your 20:80 PG-water mixture, the solubility of diazepam is 0.148 mg/mL at a temperature of 25C [1]. This means that at most 7.4mg diazepam can be dissolved in 50mL of this mixture. This is very borderline for your 5mg diazepam dose (low sink factor); diazepam may precipitate in the mixture, especially given that it is unknown how the excipients in the tablet may affect its solubility in it, so your dosing may be inaccurate.

A 60:40 PG-water mixture is preferable in terms of solubility (1.57 mg/mL) [1], but not in terms of safety; this results in 30mL PG for 50mL mixture, i.e. 31.2g PG, which is not safe for prolonged use, and even possibly acutely toxic. I invite you to read my research on the safety of PG as a solvent for diazepam in my other post: http://www.benzobuddies.org/forum/index.php?topic=267260.msg3372864#msg3372864

If you are able to tolerate it, a better option (solubility and safety wise) is homogenized whole cow milk (0.37 mg/mL at 25C, i.e. 50mL can dissolve up to 18.5mg diazepam). It is important that it first be brought up to temperature gently, at 25C or above, before being measured. Otherwise, light coconut milk may be a viable alternative; the same considerations for temperature apply to it too.

[1] Shayanfar, A., Acree Jr, W. E., & Jouyban, A. (2009). Solubility of lamotrigine, diazepam, clonazepam, and phenobarbital in propylene glycol+ water mixtures at 298.15 K. Journal of Chemical & Engineering Data, 54(3), 1153-1157. https://doi.org/10.1021/je800931z