PRL-8-53 explained

PRL-8-53 is a nootropic substituted phenethylamine that has been shown to act as a hypermnesic drug in humans; it was first synthesized by medical chemistry professor Nikolaus Hansl at Creighton University in the 1970s as part of his work on amino ethyl meta benzoic acid esters.^{[1] [2]}

Mechanism of action

The exact mechanism of action of PRL-8-53 remains unknown. Doses up to 200 mg/kg are not observed to have stimulant properties, and a dosage of 20 mg/kg does not potentiate the effects of dextroamphetamine in rats. It displays possible cholinergic properties, and potentiates dopamine while partially inhibiting serotonin. PRL-8-53 reverses the catatonic and ptotic effects of reserpine.

Toxicity

PRL-8-53 is relatively non-toxic, with an oral in mice of 860 mg/kg, giving the drug a high therapeutic index. Doses above 8 mg/kg have brief hypotensive effects in canines. High doses depress motor activity in the rat and mouse, with the ED₅₀ for a 50% reduction in motor activity of mice at 160 mg/kg. PRL-8-53 displays spasmolytic effects.^[3]

Reasons for discontinuation

It is uncertain as to exactly why PRL-8-53's development was halted. PRL-8-53 did not exhibit obvious side effects that would warrant discontinuation in animals or in its single human trial. Factors not limited to the retirement of Dr. Nikolaus Hansl in 1985 and a lawsuit filed between Hansl and Creighton University may be to blame.

Hansl v. Creighton University

On July 1, 1985 Dr. Nikolaus Hansl entered into a settlement agreement with Creighton University.^[4] The terms of the agreement guaranteed Dr. Hansl access to his laboratory facilities and office space at the university for a period of 2 years. Upon returning from a 4-month absence. Hansl found that the refrigerator he had used to store various experimental compounds had been unplugged, purportedly rendering the compounds unusable.

It is uncertain if samples of PRL-8-53 were stored in the fridge or if they would have been degraded significantly under room temperature conditions.

Patent

Dr. Hansl's patent for the synthesis of PRL-8-53 has expired.^[5]

Synonyms

Methyl 3-(2-(benzylmethylamino)ethyl)benzoate hydrochloride
3-(2-benzylmethylaminoethyl) benzoic acid methyl ester hydrochloride
3-(2-(Methyl(phenylmethyl)amino)ethyl)benzoic acid methyl ester hydrochloride

See also

• Nootropic

Notes and References

1. Hansl NR, Mead BT . 21036209 . PRL-8-53: enhanced learning and subsequent retention in humans as a result of low oral doses of new psychotropic agent . Psychopharmacology . 56 . 3 . 249–53 . April 1978 . 418433 . 10.1007/BF00432846 .
2. https://patents.google.com/patent/US3870715 US Patent 3870715 A: Substituted amino ethyl meta benzoic acid esters
3. Hansl NR . 918343 . A novel spasmolytic and CNS active agent: 3-(2-benzylmethylamino ethyl) benzoic acid methyl ester hydrochloride . Experientia . 30 . 3 . 271–2 . March 1974 . 4824605 . 10.1007/BF01934822 .
4. Web site: Hansl v. Creighton University . 2022-10-16 . Justia Law . en.
5. Nikolaus R. Hansl; Process for hydrolyzing 3-trifluoromethyl phenethylamines (US patent 3 792 048) 1974