125-58-6

The stereoselective analysis and separation of racemic drugs play an important role in pharmaceutical industry to eliminate the unwanted isomer and find the right therapeutic control for the patient. Present study suggests a maltodextrin-modified capillary electrophoresis method for a single‐run chiral separation of two closely similar opiate pain relief drugs: tramadol (TRA) and methadone (MET). The best separation method possible for the both enantiomers was achieved on an uncoated fused‐silica capillary at 25°C using 100 mM phosphate buffer (pH 8.0) containing 20% (w v?1) maltodextrin with dextrose equivalent of 4–7 and an applied voltage of 16 kV. Under optimal conditions, the baseline resolution of TRA and MET enantiomers was obtained in less than 12 minutes. The relative standard deviations (n = 3) of 20 μg mL?1 TRA and MET were 2.28% and 3.77%, respectively. The detection limits were found to be 2 μg mL?1 for TRA and 1.5 μg mL?1 for MET. This method was successfully applied to the measurement of drugs concentration in their tablets, urine, and plasma samples.

The present invention discloses an improved process for preparing pure (dimethylarnino)-4,4-diphenyl-3-heptanone and its hydrochloride salt.

(R)-6-(dimethylamino)-4,4-diphenylheptan-3-one and a process to produce thereof.

Methods for producing methadone and its resolution to produce (R)-6-dimethylamino-4,4-diphenylheptan-3-one ((R)- methadone). Such methods producing first the precursor compound 4-(dimethylamino)-2,2-diphenylpentanitrile. Oxidation of 4-(dimethylamino)-2,2-diphenylpentanitrile with ethyl magnesium halide and hydrolysis with of the complex to form 6-dimethylamino-4,4-diphenylheptan-3-one. Resolution to the (R)-isomer is effected by reaction with a bromocamphor salt. Once isolated the (R)-isomer is crystallised.

Active compound combinations of compounds of group A, particularly opioids, and compounds of group B, particularly anti-muscarine agents and other substances suitable for treatment of an increased urge to urinate or urinary incontinence. Related pharmaceutical formulations and methods of treatment of an increased urge to urinate or urinary incontinence are also provided.