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Summary

A reversed-phase ion-pairing liquid chromatographic (RP-IP-HPLC) method for simultaneous assay of theophylline (TH), phenobarbital (PB), codeine (CD), and ephedrine (EP) in an extemporaneous (magistral) suppository was developed and validated and used to investigate a reported serious adverse event. Samples were dissolved in dichloromethane and extracted by two-step liquid-liquid extraction with acetate buffer (pH 5.0) and, subsequently, 0.1 m NaOH solution. Separation was performed on an end-capped C18 silica column with stepwise gradient elution. Sample preparation and chromatographic conditions were optimized on the basis of the pK a values of the analytes. Freedom from interference from the excipients, linearity (r 2 > 0.999 for all the active ingredients), range (0.01–0.08 mg mL−1 for TH, CD, and EP; 0.0025–0.02 mg mL−1 for PB), intra-day and inter-day precision, and accuracy (recovery >95% for TH, CD, and EP and >90% for PB) of the method were demonstrated. Non-compliance of the examined product was confirmed.

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Abstract  

A new co-crystal of theophylline and phthalic acid with 1:1 molar ratio has been prepared. It crystallises in the monoclinic crystal system, space group P21/c, a=11.5258(9), b=10.1405(6), c=13.9066(12) Å, β=106.827(4)°. The structure of the co-crystal has been revealed by single crystal X-ray diffraction. An infinite helical polymeric chain is formed by intermolecular hydrogen bonds of the two neutral constituents. The hydroxyl group and carbonyl oxygen atom in one of the carboxyl groups of phthalic acid form hydrogen bonds to O6 and to N(7)H atoms of theophylline, respectively, while the other carboxyl OH group of phthalic acid is in hydrogen bond to N9 atom of theophylline by very strong intermolecular interactions proven by 1883 cm−1 centred peak in FTIR spectrum. Thermal degradation of this new supramolecular compound is a two-step process in air. At first phthalic acid (47.4%) released up to 230°C, meanwhile it loses water and transforms into phthalic anhydride. In EGA-MS spectra, the characteristic fragments of water (m/z=17, 18) appear from about 180°C, while absorption bands of phthalic anhydride are shown in EGA-FTIR spectrum at about 210°C. In the second step theophylline begins to sublime, melts at 276°C, and then evaporates up to 315°C with minute residues.

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at an early identification of all possible crystalline modifications, are nowadays a fundamental step in the pharmaceutical development of new drugs and drug products [ 1 ]. Theophylline-7-acetic acid (1,2,3,6-tetrahydro-1,3-dimethyl-2

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G. Hymel , Toxicity, theophylline. www.emedicine.com/EMERG/topic577.htm. 2006. M.H. Abdel-Hay, M.S el-Din and M.A. Abuirjeie , Analyst 117 (1992) 157

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Abstract  

The physicochemical properties of theophylline hydrate and anhydrous polymorphic forms I and II were evaluated using crystallographic and calorimetric method. This study has been carried out with the following techniques: differential scanning calorimetry (DSC), thermogravimetric analysis (TG) and X-ray diffractometry. The X-ray patterns on powder for investigated compounds are presented.

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Abstract  

Thermal stability and structural features of three newly synthesized 1:1 lattice compounds of theophylline (th) with ethylenediamine carbamate (enCO 2), 1,10-phenanthroline (phen), and 5-sulfosalicylic acid (sa-5-SO 3 H) have been studied in comparison with those of the theophylline compounds with ethanolamine (ea) and salicylic acid (sa). Simultaneous TG-DTA measurements, FTIR spectroscopy and X-ray diffraction have been carried out to get information on the various structural units of these solid inclusions, especially on the actual form (molecule, anion or cation) of theophylline moieties built in. Theophyllinate and theophyllinium ions have been found in the ethanolammonium-theophyllinate (1:1) (1, eaH + th -) and the theophyllinium salicylic acid 5-sulfonate monohydrate (1:1:1), (5, thH + saSO 3 H 2 O), respectively. Whilst the 1:1 complexes with 1,10-phenanthroline (2, thphen), ethylenediamine carbamate (3, thenCO 2), and salicylic acid (4, thsa) contain neutral theophylline moieties associated with H-bonds. In compound (3) the zwitterion of N-(2-ammonium-ethyl)carbamate (NH3 +-CH2-CH2-NH-CO- 2) is present.

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Journal of Thermal Analysis and Calorimetry
Authors: G. Rezaei Behbehani, A. Saboury, S. Tahmasebi Sarvestani, M. Mohebbian, M. Payehghadr, and J. Abedini

Abstract  

The thermodynamic parameters of interaction between theophylline and Human Serum Albumin (HSA) in buffer solution (30 mM) of pH = 7 at 27 °C was investigated by isothermal titration calorimetry (ITC). The thermodynamic quantities of the binding mechanism, the number of binding sites (g), the dissociation binding constant (K d), the molar enthalpy of binding (ΔΗ) and other thermodynamic parameters can be obtained by the extended solvation theory.

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Abstract  

Four new complex compounds were prepared by the reaction of zinc bromobutyrate and organic ligands. The general formula of the synthetized complex compounds are (2-Brbut)2ZnL and (4-Brbut)2ZnL2 nH2O (but=butyrate, L=theobromine (tbr), theophylline (tph), methyl-3-pyridyl carbamate (mpc), n=0-1). The compounds were characterized by chemical analysis and IR spectroscopy. The thermal behaviour of the zinc(II) complexes was studied by thermal analysis. Thermal decomposition in the case of hydrated compounds starts with the release of water molecules. Then molecules of organic ligands and the bromobutyrate anion are released and decomposed. CH3CH2CH=O, CO, CH2=CHCH=O, CH2O and ZnBr2 were found as gaseous products of thermal decomposition during heating up to 700°C. IR, mass spectroscopy, X-ray powder diffraction and chemical analysis were used for the determination of solid and gaseous intermediates and products of the thermal decomposition.

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Abstract  

New zinc(II) salicylate complex compounds of general formula (X-C6H3-2-(OH)COO)2Zn · Ln · xH2O (where X = H, 5-Cl; L = theophylline, urea; n = 2, 4; x = 1, 2, 4) were prepared and their thermal, spectral and biological properties were studied. It was found that the thermal decomposition of hydrated compounds starts with the release of water. During the thermal decomposition of anhydrous compounds, the release of salicylic acid, theophylline, urea, CO2, H2O and C6H5Cl takes place. Zinc oxide was found as the final product of the thermal decomposition heated up to 900 °C. The complexes were tested against bacteria, yeasts and filamentous fungi. The highest biological activity show 5-chlorosalicylate compounds.

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