Solid state compatibility study and characterization of a novel degradation product of tacrolimus in formulation.

Solid state compatibility study and characterization of a novel degradation product of tacrolimus in formulation.

Journal of pharmaceutical and biomedical analysis (2015-03-26)

Tanja Rozman Peterka, Rok Grahek, Jure Hren, Andrej Bastarda, Jure Bergles, Uroš Urleb

ABSTRACT

Tacrolimus is macrolide drug that is widely used as a potent immunosuppressant. In the present work compatibility testing was conducted on physical mixtures of tacrolimus with excipients and on compatibility mixtures prepared by the simulation of manufacturing process used for the final drug product preparation. Increase in one major degradation product was detected in the presence of magnesium stearate based upon UHPLC analysis. The degradation product was isolated by preparative HPLC and its structure was elucidated by NMR and MS studies. Mechanism of the formation of this degradation product is proposed based on complementary degradation studies in a solution and structural elucidation data. The structure was proven to be alpha-hydroxy acid which is formed from the parent tacrolimus molecule through a benzilic acid type rearrangement reaction in the presence of divalent metallic cations. Degradation is facilitated at higher pH values.

MATERIALS

Product Number

Brand

Product Description

606766

Sigma-Aldrich

Acetic acid-¹²C₂, 99.9 atom % ¹²C

699608

Sigma-Aldrich

Phosphoric acid solution, NMR reference standard, 85% in D₂O (99.9 atom % D), NMR tube size 3 mm × 8 in.

698822

Sigma-Aldrich

Phosphoric acid solution, NMR reference standard, 85% in D₂O (99.9 atom % D), NMR tube size 5 mm × 8 in.

CDS000001

Sigma-Aldrich

Magnesium citrate, Aldrich^CPR

549649

Sigma-Aldrich

Magnesium oxide, nanopowder, ≤50 nm particle size (BET)

W200603

Sigma-Aldrich

Acetic acid, natural, ≥99.5%, FG

W200611

Sigma-Aldrich

Acetic acid, ≥99.5%, FCC, FG

529699

Sigma-Aldrich

Magnesium oxide, ≥99.99% trace metals basis

72068

Sigma-Aldrich

Sodium hydroxide solution, BioUltra, for molecular biology, 10 M in H₂O

71687

Sigma-Aldrich

Sodium hydroxide, BioUltra, for luminescence, ≥98.0% (T), pellets

450146

Sigma-Aldrich

Calcium hydroxide, 99.995% trace metals basis

282979

Sigma-Aldrich

3-Ethyl-2,4-pentanedione, mixture of tautomers, 98%

63138

Sigma-Aldrich

Magnesium sulfate heptahydrate, BioUltra, ≥99.5% (KT)

45726

Sigma-Aldrich

Acetic acid, for luminescence, BioUltra, ≥99.5% (GC)

612162

Sigma-Aldrich

Phosphoric acid solution, NMR reference standard, 85% in D₂O (99.9 atom % D), NMR tube size 4.2 mm × 8 in. , WGS-5BL Coaxial NMR tube

W290017

Sigma-Aldrich

Phosphoric acid solution, 85 wt. % in H₂O, FCC, FG

203718

Sigma-Aldrich

Magnesium oxide, 99.99% trace metals basis

S2770

Sigma-Aldrich

Sodium hydroxide solution, 1.0 N, BioReagent, suitable for cell culture

M5921

Sigma-Aldrich

Magnesium sulfate heptahydrate, BioXtra, ≥99.0%

M2773

Sigma-Aldrich

Magnesium sulfate heptahydrate, BioReagent, for molecular biology, suitable for plant cell culture, ≥99.0%

757527

Sigma-Aldrich

Sodium hydroxide, ultra dry, powder or crystals, 99.99% trace metals basis

634646

Sigma-Aldrich

Magnesium oxide, (single crystal substrate), ≥99.9% trace metals basis, <100>, L × W × thickness 10 mm × 10 mm × 0.5 mm

609781

Sigma-Aldrich

Phosphoric acid-¹⁶O₄ solution, 70 wt. % in D₂O, 99.9 atom % ¹⁶O

733466

Sigma-Aldrich

Acetonitrile, electronic grade, 99.999% trace metals basis

609765

Sigma-Aldrich

Sodium hydroxide-¹⁶O solution, 20 wt. % in H₂¹⁶O, 99.9 atom % ¹⁶O

466123

Sigma-Aldrich

Phosphoric acid, crystalline, ≥99.999% trace metals basis

271004

Sigma-Aldrich

Acetonitrile, anhydrous, 99.8%

W222402

Sigma-Aldrich

Caffeine, anhydrous, 99%, FCC, FG

345245

Sigma-Aldrich

Phosphoric acid, 85 wt. % in H₂O, 99.99% trace metals basis

W303518

Sigma-Aldrich

Stearic acid, ≥95%, FCC, FG