RB-120 (benzyl (2S)-2-propanoate) is an orally active
analog
Analog or analogue may refer to:
Computing and electronics
* Analog signal, in which information is encoded in a continuous variable
** Analog device, an apparatus that operates on analog signals
*** Analog electronics, circuits which use analog ...
of the drug
RB-101
RB-101 is a drug that acts as an enkephalinase inhibitor, which is used in scientific research.
RB-101 is a prodrug which acts by splitting at the disulfide bond once inside the brain, to form two selective enzyme inhibitors and blocking both ty ...
.
It acts as an
enkephalinase inhibitor
An enkephalinase inhibitor is a type of enzyme inhibitor which inhibits one or more members of the enkephalinase class of enzymes that break down the endogenous enkephalin opioid peptides. Examples include racecadotril, ubenimex (bestatin), RB-1 ...
, which is used in scientific research. Via intravenous administration, it is approximately three times as potent as RB-101 or twice as potent as the isolated (S,S) isomer of RB101. However, via
i.p. administration it is approximately twice as potent as
racemic
In chemistry, a racemic mixture, or racemate (), is one that has equal amounts of left- and right-handed enantiomers of a chiral molecule or salt. Racemic mixtures are rare in nature, but many compounds are produced industrially as racemates. ...
RB-101 and about as potent as the isolated (S,S) isomer of RB101. During
i.v. administration RB120 is approximately twice as weak as
morphine
Morphine is a strong opiate that is found naturally in opium, a dark brown resin in poppies (''Papaver somniferum''). It is mainly used as a pain medication, and is also commonly used recreationally, or to make other illicit opioids. T ...
in terms of
analgesia
Pain management is an aspect of medicine and health care involving relief of pain (pain relief, analgesia, pain control) in various dimensions, from acute and simple to chronic and challenging. Most physicians and other health professional ...
, however it is 16x weaker during i.p. and
p.o. administration.
Dosage
RB 120 produces a significant dose-dependent antinociceptive response in the rat tail-flick test at 10 and 25 min after i.v. administration, at doses of 12.5, 25 and 50 mg/kg.
The analgesic effect occurred with a slower onset compared to typical IV opioids likely due to the fact that, following enkephalinase inhibition, it may take some time for endogenous enkephalin to accumulate without degradation until sufficient concentration is reached for analgesic effect, whereas for opioids, onset only requires entry into the brain via the
blood–brain barrier which occurs rapidly for lipophilic molecules, and binding to the opioid receptor produces a near-instantaneous G-protein mediated response and production of second messenger, without need for de novo synthesis of any neurotransmitters.
References
Enkephalinase inhibitors
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