Lots of thoughts about liquid deprenyl:
It seems that Dep Pro is the citrate version, from what's buried deep in the
description:
Deprenyl tablets are selegiline hydrochloride, which is deprenyl bonded to an in-organic molecule. However, liquid deprenyl citrate (LDC) is selegiline bonded to an organic molecule, one reason why the liquid deprenyl citrate is considered to be superior. This form is generally recognized as the most pure and potent form of deprenyl available. It also allows precise titration for anti-aging purposes, as each ml drop in the bottle is equivalent to 1mg deprenyl citrate.
Again there's mention of a "general recognition" that citrate is the most pure and potent form available. This seems pretty silly to me, in absence of any current evidence...the pharmaceuticals doctors use to treat Parkinson's are not of inferior quality to a product available on a website, manufactured by an unidentifiable person or company. Hydrochloride is one of the most common salts in drug manufacture, and I've never heard someone say that citrate is better because it's an organic molecule (choosing drug salts is not the same as shopping for tomatoes). It's just more smokescreen to "poison the well" regarding the shockingly cheap Indian generics (which are still made by identifiable, established pharmaceutical companies).
I would expect both HCl and citrate to have very similar characteristics when absorbed through the mouth. To reiterate, the citrate version is not
privileged over other salts, no matter what product descriptions say. If anything, the complete lack of citrate data and accountability of manufacture makes it the other way around.
Sublingual deprenyl has several advantages, but also some key differences which may be highly undesirable for some. First, the bioavailability is much higher: at least 75% of oral DPR is lost to first-pass metabolism [
1], resulting in a maximum of 20% availability if taken with food (and more like 5%, without). In the original human study of Zydis (crushable HCl tablets absorbed bucally and sublingually), 1.25mg sublingual HCl produced similar plasma levels and whole-body MAO-B inhibition as 10mg oral [
2]. This should be considered when computing dosage, especially if avoiding any MAO-A inhibition is critical.
In general, it should be expected that sublingual administration produces a more immediate subjective response due to the immediate delivery to the bloodstream. Another difference in the pharmacokinetics is that sublingual DPR produced more consistent levels in the bood than oral DPR. For those who think sublingual dosing is preferable, it should be possible to make a solution at home from DPR tablets. Basically, crush them as finely as possible and soak/stir 3x in a pre-measured amount of water.
Second, the MAO inhibition profile changes when administered sublingually. When taken orally, much of the dose is "used up" inhibiting MAO in the GI tract [
3]. MAO in these areas is responsible for the metabolism of tyramine [
4], which explains the finding that sublingual DPR HCl (which bypasses the stomach) had no effect on the amount of tyramine necessary to produce a crisis (while oral DPR cut it in half) [
5]. However, the original human study of Zydis found that 1.25mg sublingual HCl produced
more total-body MAO-A inhibition than 10mg oral [2].
What all this strongly suggests is that sublingual DPR results in a higher level of brain MAO-A inhibition than an equivalent dose of oral DPR...perhaps by as much as 10x. (This proportional increase might apply somewhat to MAO-B as well, but as even a single 10mg oral dose inhibits MAO-B by as much as 98% [6], this probably isn't relevant except at very low dosages). There are several threads here discussing how safe it is to combine SSRIs with deprenyl (safety depends on MAOI-B selectivity), but it should be remembered that these calculations are based entirely on the data established by oral dosing, and more extreme caution should be exercised with liquid dosing.
There are also several good posts by aidanpryde earlier in this (merged) thread, concerning the possibility that the metabolites produced mostly in first-pass metabolism (which sublingual bypasses) are responsible in part for the mental effects of the drug.
[6] Ahola R, Haapalinna A, Heinonen E. et al. Protection by L-deprenyl of intact peripheral sympathetic neurons exposed to neurotoxin 6-hydroxy-dopamine (6-OHDA). 11th Symposium of Parkinson's Disease, Rome, March 26–30, 1994. New Trends Clin Neuropharamcol. 1994;7:287.
Edited by chrono, 11 October 2011 - 04:30 PM.