Isopropylphenidate is a compound synthesized from the substituted phenethylamine and phenidate groups. It has a phenethylamine core with a phenyl ring that is connected to an amino (NH2) group through an ethyl chain. It has a similar structure to amphetamine, with a substitution at R that is then inserted into a piperidine ring that ends at the terminal amine of the phenethylamine chain. Furthermore, it has an isopropyl acetate bound to R of its molecular structure, which differs from methylphenidate, which has a methyl group in this position.
The length of the carbon chain on their acetate group distinguishes isopropylphenidate from ethylphenidate and methylphenidate structurally. Iso- refers to the side chain of one carbon atom that branches into two bound methyl groups, phen- refers to the phenyl ring, id- refers to the piperidine ring, and -ate refers to the acetate group. Isopropylphenidate is a chiral compound that has been shown to be formed as a racemic mixture and exclusively as one of its enantiomers.
There have been no systematic in vivo human research using isopropylphenidate; however, in vivo rat studies and in vitro studies have been performed to observe the stimulatory effects in rats and to test the monoamine transporter binding affinities and affinities for various hydrolytic enzymes. According to the findings of these studies, isopropylphenidate has a very similar pharmacology to its parent compound methylphenidate, with the main differences being that isopropylphenidate has significantly less activity as a norepinephrine reuptake inhibitor and the CES1 hydrolytic enzyme, which is solely responsible for hydrolyzing all substances to ritalinium.
Because of these variations, the drug has more pronounced dopaminergic activity than adrenergic activity as compared to methylphenidate at equal effective dosages, as well as a longer duration and greater potency than methylphenidate at a given dose. The greater potency of isopropylphenidate compared to methylphenidate is most evident when administered orally, as the discrepancy in potency is due to the lower affinity of CES1 increasing bioavailability of isopropylphenidate compared to methylphenidate, which is especially poor for methylphenidate when administered orally due to first-pass metabolism in the liver by CES1.
Despite the differences, isopropylphenidate is thought to act primarily as a dopamine reuptake inhibitor and a norepinephrine reuptake inhibitor, which means that it effectively increases the levels of norepinephrine and dopamine neurotransmitters in the brain by binding to and partially blocking the transporter proteins that normally remove those monoamines. This causes dopamine and norepinephrine to build up in the brain, causing stimulatory effects.