Chemiluminescence data modeling using parallel factor analysis for the simple and sensitive determination of diphenoxylate in human plasma and tablets.

In this study, a chemiluminescence (CL) method was developed to determine diphenoxylate in tablets and human plasma. This is the first CL method proposed to determine diphenoxylate. Creating three-dimensional data caused the parallel factor analysis algorithm (PARAFAC) to be used for the first time in CL methods. The method is based on the fact that diphenoxylate enhances the weak CL produced in the reaction of Ru(phen)3 2+ and acidic Ce(IV), and the concentration of Ce(IV) solution has a different effect on the CL response of diphenoxylate and the blank plasma. The calibration curve was linear from 4.0 × 10-8 to 1.6 × 10-6 mol L-1 (R2 = 0.9954), and the detection limit was 1.3 × 10-8 mol L-1 (S/N = 3). The sampling rate was about 30 samples per hour, and the % RSD for 10 repeated measurements of 4 × 10-7 mol L-1 diphenoxylate was 5.4%. The interference effects of some ions, amino acids, and common additives were also investigated. The CL method was successfully used to determine diphenoxylate in tablets, and the results were statistically confirmed by the reference method. The proposed CL method and the PARAFAC algorithm were successfully used to determine the concentration of diphenoxylate in human blood plasma samples.

Principal component and correlation analysis of biochemical and endocrine markers in a healthy pediatric population (CALIPER).

BACKGROUND: Reference intervals (i.e. normative ranges) established from a healthy reference population are essential to accurately interpret disease biomarkers. Biomarker concentration may partially depend on associations with other biomarkers due to various physiological and pathophysiological processes. In this study, a robust correlation analysis was performed to identify physiological biomarker associations in the healthy pediatric CALIPER cohort. METHODS: Population reference values for 35 biochemical and 20 fertility/endocrine markers were analyzed for correlations in all subjects, male adolescents, female adolescents, and young children. Associations between biomarkers were assessed by Spearman's rank correlation and a multivariate analysis technique, principal component analysis (PCA). RESULTS: Of 197, 90, 59, and 32 significant correlations between biochemical markers in all subjects, male adolescents, female adolescents, and children, respectively, 23, 19, 16, and 9 were moderately strong (r > 0.5 or r < -0.5). Of 98, 24, 33, and 16 significant correlations between fertility/endocrine markers in all subjects, male adolescents, female adolescents, and children, respectively, 17, 8, 11, and 5 were moderately strong. Results were agreeable between Spearman's rank method and PCA. In some cases, biomarker correlations differed between sexes. CONCLUSIONS: Using PCA, this study provides for the first time an extensive analysis of circulating biomarker associations in a healthy pediatric cohort. These data can inform future studies of potential confounding factors or particular variables that should be considered in test result interpretation for specific diseases.

Hydroxonium hydrate tris-(2,4,6-tri-amino-1,3,5-triazin-1-ium) bis-[bis-(pyri-dine-2,6-dicarboxyl-ato)cuprate(II)] pyridine-2,6-dicarboxylic acid hexa-hydrate.

The reaction of copper(II) nitrate hexa-hydrate with pyridine-2,6-dicarboxylic acid (pydcH(2)) and 2,4,6-triamino-1,3,5-triazine (melamine) in aqueous solution in a 1:2:2 molar ratio gave the title compound, (H(5)O(2))(C(3)H(7)N(6))(3)[Cu(C(7)H(3)NO(4))(2)](2)·C(7)H(5)NO(4)·6H(2)O. The hydroxonium hydrate (H(5)O(2))(+), also known as the Zundel cation, resides on a twofold rotation axis. The O-H distance is 1.274 (14) Å, the O⋯O distance is 2.518 (5) Å, and the O-H-O angle is 162 (8)°. One of the melamine H(+) cations, the uncoordinated pydcH(2), and two water mol-ecules also reside on crystallographic twofold axes. The Cu(II) atom has a tetra-gonally distorted octa-hedral coordination environment. The structure features extensive hydrogen bonding, with 21 distinct inter-actions. There is also a centrosymmetric C=O⋯π inter-action with an O⋯centroid distance of 3.288 (3) Å. The structure is similar to a mixed-valence manganese(II/III) structure but shows inter-esting differences in the metal-atom coordination. One of the water molecules is equally disordered with respect to a twofold axis.

Poly[propane-1,3-diammonium [cuprate(II)-bis-(µ(2)-pyridine-2,3-dicarboxyl-ato)] trihydrate].

The title polymeric compound {(C(3)H(12)N(2))[Cu(C(7)H(3)NO(4))(2)]·3H(2)O}(n) or {(pnH(2))[Cu(py-2,3-dc)(2)]·3H(2)O}(n) (pn is propane-1,3-diamine and py-2,3-dcH(2) is pyridine-2,3-dicarboxylic acid), was synthesized by reaction of copper(II) chloride dihydrate with a proton-transfer compound, propane-1,3-diammonium pyridine-2,3-dicarboxyl-ate or (pnH(2))(py-2,3-dc), in aqueous solution. The anion is a six-coordinate complex (site symmetry ), with a distorted octa-hedral geometry around Cu(II), consisting of two bidentate pyridine-2,3-dicarboxyl-ate groups and two O atoms of bridging ligands from (py-2,3-dc)(2-) fragments, which are located in trans positions. The (pnH(2))(2+) cation is disordered over two sites by the center of inversion. Inter-molecular hydrogen bonds, π-π [centroid-centroid distances of 3.539 (3) Å] and C-O⋯π stacking inter-actions [O⋯Cg = 3.240 (5) Å; Cg is the center of the pyridine ring], connect the various components into a supra-molecular structure.

4-(4-Pyrid-yl)pyridinium bis-(pyridine-2,6-dicarboxyl-ato)chromium(III) tetra-hydrate.

The title compound, (C(10)H(9)N(2))[Cr(C(7)H(3)NO(4))(2)]·4H(2)O or (4,4'-bipyH)[Cr(pydc)(2)]·4H(2)O (where 4,4'-bipy is 4,4'-bipyridine and pydcH(2) is pyridine-2,6-dicarboxylic acid), was synthesized by the reaction of chromium(III) chloride hexa-hydrate with pyridine-2,6-dicarboxylic acid and 4,4'-bipyridine in a 1:2:4 molar ratio in aqueous solution. This compound is composed of an anionic complex, [Cr(pydc)(2)](-), protonated 4,4'-bipyridine as a counter-ion, (4,4'-bipyH)(+), and four uncoordinated water mol-ecules. The anion is a six-coordinate complex with a distorted octa-hedral geometry around the Cr(III) atom, formed by two tridentate pyridine-2,6-dicarboxyl-ate, pydc(2-), groups. Inter-molecular O-H⋯O, N-H⋯O and C-H⋯O hydrogen bonds, and C-O⋯π stacking inter-actions (with distances of 3.3390 (13) and 3.4575 (13) Å) connect the various components into a supra-molecular structure.

2-(2-Pyrid-yl)pyridinium bis-(pyridine-2,6-dicarboxyl-ato-κO,N,O')aluminate(III) trihydrate.

The title compound, (C(10)H(9)N(2))[Al(C(7)H(3)NO(4))(2)]·3H(2)O or (2,2'-bipyH)[Al(pydc)(2)]·3H(2)O (where 2,2'-bipy is 2,2'-bipyridine and pydcH(2) is pyridine-2,6-dicarboxylic acid), was synthesized by the reaction of aluminium(III) nitrate nona-hydrate with pyridine-2,6-dicarboxylic acid and 2,2'-bipyridine in a 1:2:4 molar ratio in aqueous solution. This compound is composed of an anionic complex, [Al(pydc)(2)](-), a protonated 2,2'-bipyridine mol-ecule as a counter-ion, (2,2'-bipyH)(+), and three uncoordinated water mol-ecules. The anion is a six-coordinate complex, with the Al(III) atom in a distorted octa-hedral geometry coordinated by two tridentate pyridine-2,6-dicarboxyl-ate groups. In the crystal structure, inter-molecular O-H⋯O, N-H⋯O, N-H⋯N and C-H⋯O hydrogen bonds, π-π stacking between two aromatic rings [centroid-centroid distance = 3.827 (10) Å], and C=O⋯π stacking [with distances of 3.2311 (13), 3.4924 (14) and 3.5731 (13) Å], connect the various components to form a supra-molecular structure.