Skip to Content
Merck
  • Enantioselective nano liquid chromatographic separation of racemic pharmaceuticals: a facile one-pot in situ preparation of lipase-based polymer monoliths in capillary format.

Enantioselective nano liquid chromatographic separation of racemic pharmaceuticals: a facile one-pot in situ preparation of lipase-based polymer monoliths in capillary format.

Chirality (2014-03-08)
Marwa Ahmed, Ashraf Ghanem
ABSTRACT

New affinity monolithic capillary columns of 150 µm internal diameter were prepared in situ fused glass capillary via either immobilization or encapsulation of Candida antarctica lipase B (CALB) on or within polymer monoliths, respectively. The immobilized lipase-based monoliths were prepared via copolymerization of 19.1% monomers (8.9% MMA and 10.2% GMA), 19.8% EDMA, and 61.1% porogens (54.2% formamide and 6.9% 1-propanol) w/w or 20% GMA, 20% EDMA, and 60% porogens (51.6% cyclohexanol and 8.4% 1-dodecanol) in the presence of AIBN (1%) as a radical initiator. This was followed by pumping a solution of lipase through the capillaries and rinsing with potassium phosphate buffer. On the other hand, the encapsulated lipase-based monoliths were prepared via copolymerization of 20% monomers (GMA), 20% EDMA, and 60% porogens (48% 1-propanol, 6% 1,4-butanediol) or 16.4% monomers (16% BuMA, 0.4% SPMA), 23.6% EDMA, and 60% porogens (36% 1-propanol, 18% 1,4-butanediol along with 6% lipase aqueous solution in potassium phosphate buffer. The prepared capillary columns were investigated for the enantioselective nano liquid chromatographic separation of a set of different classes of racemic pharmaceuticals, namely, α- and β-blockers, antiinflammatory drugs, antifungal drugs, dopamine antagonists, norepinephrine-dopamine reuptake inhibitors, catecholamines, sedative hypnotics, diuretics, antihistaminics, anticancer drugs, and antiarrhythmic drugs. Run-to-run repeatability was quite satisfactory. The encapsulated lipase-based capillary monolith showed better enantioselective separations of most of the investigated compounds. Baseline separation was achieved for alprenolol, atenolol, bromoglutithimide, carbuterol, chloropheneramine, cizolertine carbinol, 4-hydroxy-3-methoxymandelic acid, desmethylcizolertine, nomifensine, normetanephrine, and sulconazole under reversed phase chromatographic conditions. A speculation about the understanding of the chiral recognition mechanism of lipase-based monoliths toward the investigated pharmaceuticals is discussed.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
Methanol-12C, 99.95 atom % 12C
Sigma-Aldrich
Potassium phosphate monobasic, 99.99% trace metals basis
Sigma-Aldrich
Methanol solution, NMR reference standard, 4% in methanol-d4 (99.8 atom % D), NMR tube size 3 mm × 8 in.
Sigma-Aldrich
Potassium phosphate dibasic, anhydrous, for luminescence, for molecular biology, BioUltra, ≥99.0% (T)
Supelco
Ethanol, standard for GC
Sigma-Aldrich
Ethanol, tested according to Ph. Eur.
Sigma-Aldrich
Ethanol, purum, secunda spirit, denaturated with 2% 2-butanone, S15, ~96% (based on denaturant-free substance)
Supelco
Acetonitrile, analytical standard
Sigma-Aldrich
3-(Trimethoxysilyl)propyl methacrylate, 98%
Supelco
Formamide solution, NMR reference standard, 90% in DMSO-d6 (99.9 atom % D), NMR tube size 5 mm × 8 in.
Sigma-Aldrich
1,4-Butanediol, ReagentPlus®, 99%
Sigma-Aldrich
3-Sulfopropyl methacrylate potassium salt, 98%
Supelco
Trifluoroacetic acid, analytical standard
Sigma-Aldrich
Butyl methacrylate, 99%, contains monomethyl ether hydroquinone as inhibitor
Sigma-Aldrich
Potassium phosphate monobasic, tested according to Ph. Eur., anhydrous
Sigma-Aldrich
Ethanol, for residue analysis
Sigma-Aldrich
Acetonitrile, anhydrous, 99.8%
Sigma-Aldrich
Potassium phosphate dibasic, 99.95% trace metals basis
Sigma-Aldrich
Potassium phosphate monobasic, BioUltra, for molecular biology, anhydrous, ≥99.5% (T)
Sigma-Aldrich
Potassium phosphate monobasic, powder, suitable for cell culture, suitable for insect cell culture, suitable for plant cell culture, ≥99.0%
Sigma-Aldrich
Potassium phosphate monobasic, ReagentPlus®
Sigma-Aldrich
Potassium phosphate monobasic, for molecular biology, ≥98.0%
Sigma-Aldrich
Potassium phosphate dibasic solution, 1.0 M
Sigma-Aldrich
Potassium phosphate dibasic, reagent grade, ≥98.0%
Sigma-Aldrich
3-(Trimethoxysilyl)propyl methacrylate, ≥97%
Sigma-Aldrich
Potassium phosphate dibasic, meets USP testing specifications
Sigma-Aldrich
Acetonitrile, electronic grade, 99.999% trace metals basis
Sigma-Aldrich
Formamide solution, NMR reference standard, 90% in DMSO-d6 (99.9 atom % D), NMR tube size 10 mm × 8 in.
Supelco
Formamide solution, NMR reference standard, 90% in DMSO-d6 (99.9 atom % D), NMR tube size 5 mm × 8 in.
Supelco
Monobasic Potassium Phosphate, Pharmaceutical Secondary Standard; Certified Reference Material