Metoprolol applications

Lanchote, V.L., Bonato, P.S., Cerqueira, P.M., Pereira, V.A., Cesarino, E.J. Enantioselective analysis of metoprolol in plasma using highperformance liquid chromatographic direct and indirect separations applications in pharmacokinetics. J. Chromatogr. B 738, 27-37 (2000)... 

A pulsed depolarizing iontophoretic system has been developed by Advance Co. [26] that delivers a current of frequency 40 Hz and an on-off duty of 30% to deliver a significant amount of metoprolol into the blood without any observed skin irritation or erythema at the site of application. Okabe et al. [26] hypothesized that the high-frequency pulses provided low skin impedance in addition, the capacitance of the skin was restored to its initial state at the start of each pulse cycle. Chien et al. [89] reported that a sine waveform induced a faster hypoglycemic effect with insulin, with the peak at approximately 2 hours, than either a trapezoidal (7 hours) or a square waveform (12 hours) however, the duration of the hypoglycemia was also shorter (11 hours) compared with the other two waveforms [89]. 

If the wet granulation technology is applied spray-dried PVAc/Povidone should be put in the extragranular phase to avoid the wetting of this polymer mixture. Such application is shown in in Table 106 in a formulation of metoprolol sustained-release tablets. 

Uzu, S. Imai, K. Nakashima, K. Akiyama, S. Use of 4-(N,N-dimethylaminosulphonyl)-7-fluoro-2,l,3-benzoxadiazole as a labelling reagent for peroxyoxalate chemiluminescence detection and its application to the determination of the p-blocker metoprolol in serum by high-performance liquid chromatography. Analyst, 1991, 116, 1353-1357... 

Leloux, M.S. Rapid chiral separation of metoprolol in plasma-application to the pharmacokinet-ics/pharmacodynamics of metoprolol enantiomers in the conscious goat. Biomed.Chromatogr., 1992, 6, 99-105... 

Midazolam, verapamil, and metoprolol were resolved using ethyl acetate containing 0.5% ammonium hydroxide on monolithic UTLC glass-backed plates. The plates were prewashed once with acetonitrile before sample application. The UTLC plates were attached to the face of an in-house-modified AP-MALDI target plate with double-sided conductive tape after cutting the plate to match the target probe. 

Enantiomers of (-P/—)-metoprolol tartrate were separated on silica gel 60F plates using the chiral selector d-(—)-tartaric acid (11.6 mM solution) both impregnated into the layer and as mobile phase additive. The mobile phase was ethanol/water (70 30) and development temperature was 25 C. The layer was impregnated at ambient temperature for 90 min before sample application. Separated zones were detected by viewing at 254 nm, scanning at 230 nm, and exposure to iodine vapor. Rf values were 0.65 and 0.50 for the S-(—) and R-(+) enantiomers, respectively [19]. 

The following chiral reagents were employed for diastereomer formation before sample application and chromatography on silica gel or silica gel G TLC plates (L)-leucine Af-carboxyanhydride for D,L-dopa-carboxyl- " C separated with ethyl acetate/formic acid/water (60 5 35) mobile phase and detected by ninhydrin [7 f 0.38 (d)/0.56 (l)] [43] Af-trifluoroacetyl-L-prolyl chloride for D,L-amphetamine separated with chloroform/methanol (197 3) and detected by sulfuric acid/formaldehyde (10 1) (Rf 0.49 (d)/0.55 (l)) [44] Af-benzyloxycarbonyl-L-prolyl chloride for D,L-methamphetamine separated with n-hexane/ethyl acetate/acetonitrile/diisopropyl ether (2 2 2 1) and detected by sulfuric acid/formaldehyde (10 1) [/ f 0.57 (l)/0.61 (d)] [44] (l/ ,2/ )-(-)-l-(4-nitrophenyl)-2-amino-1,3-propanediol (levobase) and its enantiomer dextrobase for chiral carboxylic acids separated with chloroform/ethanol/acetic acid (9 1 0.5) and detected under UV (254 nm) light R[ values 0.63 and 0.53 for 5- and / -naproxen, respectively) [45] (5)-(4-)-a-methoxyphenylacetic acid for R,S-ethyl-4-(dimethylamino)-3-hydroxybutanoate (carnitine precursor) with diethyl ether mobile phase [/ f 0.55 R)/0J9 (5)] [46] and (5)-(4-)-benoxaprofen chloride with toluene/acetone (100 10, ammonia atmosphere) mobile phase and fluorescence visualization (Zeiss KM 3 densitometer 313 nm excitation, 365 nm emission) (respective R values of R- and 5-isomers of metoprolol, oxprenolol, and propranolol were 0.24/0.28, 0.32/0.38, and 0.32/0.39) [47]. 

The scanned profiles of chromatograms obtained applying different ( )-metoprolol tartrate concentrations on the plate are presented in Figure 11.6. It was observed that S- -) enantiomer had a higher mobility than its R-(+) counterpart. The applicability of this chromatographic system for the enantioseparation of some other /3-blockers is illustrated in Table 11.4. Racemates of atenolol, alprenolol, betaxolol, celiprolol, carvedilol, metoprolol tartrate, oxprenolol, pro-pranol, and timolol were quite well separated, while the spots of carvedilol were elongated [21,22]. 

Sample preparation Standard solution of ( )-metoprolol tartarate at a concentration 20 mg/ml was prepared in methanol. The solution was diluted with methanol to concentrations of 5 and 10 mg/ml directly before application. 

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