Mivacurium

Mivacron,GlaxoSmithKline S.p.A.,Italy

ChEBI: Mivacurium is a member of isoquinolines.

To ()-5'-methoxylaudanosine (46.4 g) in methanol (240 mL) was added (-)- dibenzoyltartaric acid monohydrate (45.2 g). The mixture was heated to boiling, cooled at 5°C for 16 h and the (S)-(-)-5'-methoxylaudanosinium dibenzoyltartrate salt (35.6 g, 80%) was filtered and discarded. The mother liquors were made basic with concentrated aqueous NaOH and evaporated under vacuum. The solid residue was partitioned between H2O and diethyl ether. The ether phase was dried and evaporated to an oil (24.9 g). To the oil in methanol (128 mL) was added (+)-dibenzoyltartaric acid monohydrate (26.6 g). The mixture was heated to boiling and cooled at 5°C for 16 h. Crystals were collected and recrystallized from methanol until a constant specific rotation of [α]D20=+17.7° (1% EtOH) had been achieved. The yield of (R)-(+)-5'-methoxylaudanosinium dibenzoyltartrate as white crystals was 29.4 g (66%). A portion of the salt (15.0 g) in methanol (200 mL) was made basic with concentrated aqueous NaOH. The mixture was evaporated under vacuum and the residue was partitioned between H2O and diethyl ether. The combined ether layers were dried and evaporated under vacuum to yield 7.2 g (92%) of (R)-(-)-5'-methoxylaudanosine as an oil.
(R)-(-)-5'-Methoxylaudanosine (7.2 g), 3-chloropropanol (3.5 g), sodium iodide (5.6 g) and sodium carbonate (0.5 g) were refluxed in 2-butanone (125 mL) for 16 h. The white suspension was filtered hot and solvent removed from the filtrate under vacuum. The residual gum was trituated with hot ethyl acetate to remove excess 3-iodopropanol, dissolved in 200 mL methanol and passed through a column packed with Dowex RTM.1-X8 ion exchange resin (60 g chloride form). The eluant was stripped of solvent under vacuum to give N-3-hydroxypropyl-1-(R)-5'-methoxylaudanosinium chloride (8.4 g) as an amophous solid. The material was assayed by HPLC as a 2.3/1 mixture of the trans/cis diastereomers.
N-3-Hydroxypropyl-1-(R)-5'-methoxylaudanosinium chloride (2.3/1, trans/cis by HPLC, 2.5 g) was dissolved in 60 mL 1,2-dichloroethane at about 70°C. (E)-4-Octene-1,8-dioic acid chloride (0.5 g) (K. Sisido, K. Sei, and H. Nozaki, J. Org. Chem., 1962, 27, 2681) was added and the mixture was stirred at ambient temperature for 19 h. Solvent was removed under vacuum to give an amorphous solid which was dissolved in chloroform (25 mL) and washed with 5% aqueous sodium chloride solution to remove unreacted quaternary salts. The chloroform layer was dried and evaporated under vacuum to give an amorphous solid. The acid ester impurities were substantially removed by washing with hot 2-butanone. Residual solvent was evaporated under vacuum and the resulting amorphous solid was dissolved in methanol, filtered and lyophilized to give 1.9 g of (E)-(1R,1'R)-2,2'-[4-octenedioylbis (oxytrimethylene)]bis[1,2,4,3-tetrahydro-6,7-dimethoxy-2-methyl-1-(3,4,5- trimethoxybenzyl)isoquinolinium] dichloride, which was assayed by HPLC as 44.6% RS-RS (trans-trans) diester, 42.4% RR-RS (cis-trans) diester, 7.5% RRRR(cis-cis) diester, 4.0% RS (trans) acid ester and 1.5% RR (cis) (E)- (1R,1'R)-2,2'-[4-Octenedioylbis(oxytrimethylene)]bis[1,2,3,4-tetrahydro-6,7- dimethoxy-2-methyl-1-(3,4,5-trimethoxybenzyl)isoquinolinium]dichloride acid ester, [α]D20=-62.7° (1.9% in water).

Muscle relaxant

Potentially hazardous interactions with other drugs
Anaesthetics: enhanced muscle relaxant effect.
Anti-arrhythmics: procainamide enhances muscle relaxant effect.
Antibacterials: effect enhanced by aminoglycosides, clindamycin, polymyxins and piperacillin.
Antiepileptics: muscle relaxant effects antagonised by carbamazepine; effects reduced by long-term use of fosphenytoin and phenytoin but might be increased by acute use.
Botulinum toxin: neuromuscular blockade enhanced, (risk of toxicity).

Mivacurium is a mixture of 3 stereoisomers, 2 of which (cis-trans and trans-trans) are considered to account for most of the neuromuscular blocking effect. All 3 isomers are inactivated by plasma cholinesterase. Renal and hepatic mechanisms are involved in their elimination with excretion in urine and bile.