Theophylline, molecular structures

Fig. 7.3. Molecular structure and suitable atomic numbering system for theophylline.

Figure 16-1. Molecular structures of caffeine (left), theophylline (center), and theobromine (right)...

Terahertz time-domain-spectroscopy has been used to distinguish between chiral and racemic hydrogen-bonded cocrystals, and could readily distinguish between the isostructural cocrystals of theophylline with the chiral and racemic forms of both malic and tartaric acids [29]. These findings are of importance since it was concluded that while the respective cocrystal systems were almost identical in molecular structure and supramolecular architecture, the use of terahertz spectroscopy was comparable in sensitivity to X-ray diffraction and more sensitive than Raman spectroscopy to changes in cocrystal architecture. Solid-state nuclear... 

Nakao, S. Fujii, S. Sakai, T. Tomita, K.-I. The crystal and molecular structure of the 2 1 molecular complex of theophylline with phenobarbital. Acta Crystallogr. 1977, B33, 1373-1378. 

The first example, depicted in Fig. 6, describes the synthesis and evaluation of a polymer imprinted with the bronchodilating drug theophylline, which is used in the treatment of asthma. Originally published in the journal Nature [2], this work drew considerable attention to the field of molecular imprinting because it was the first study to show that an MIP could be substituted for a natural antibody in a standard clinical assay. The MIP and antibody-based assays exhibit similar selectivities, and both can discriminate between theophylline and structurally related compounds. An equilibrium binding assay is described which uses radiolabeled theophylline as a marker. Data are presented for which nonradioactive theophylline, caffeine, and theobromine are used in competitive binding assays. These assays provide valuable information about the capacity and selectivity of the MIP. 

In contrast to the emphasis placed on the crystal rather than the molecular structures of the compounds discussed above, the conformation of 1,3-bis-(8-theophylline)propane (18 n = 3) is of considerable importance. This compound was studied since, of the series of compounds theophylline and... 

Zimmermann, G.R., Jenison, R.D., Wick, C.L., Simorre, J.P. and Pardi, A. (1997). Interlocking structural motifs mediate molecular discrimination by a theophylline-binding RNA. Nat. Struct. Biol. 4, 644-649. 

Figure 7.8 A schematic representation of the preparation of molecularly imprinted polymers [19]. (a) Functional monomer MAA (1) is mixed with print molecule, here theophylline (2), and EDMA, the cross-linking monomer, in suitable solvent. MAA is selected for its ability to form hydrogen bonds with a variety of chemical functionalities of the print molecule. (6) The polymerization reaction is started by addition of initiator (2,2 -azobis(2-methylpropionitrile), AIBN). A rigid insoluble polymer is formed, Imprints , which are complementary to the print molecule in both shape and chemical functionality, are now present within the polymeric network, (c) The print molecule is removed by solvent extraction. The wavy line represents an idealized polymer structure but does not take into account the accessibility of the substrate to the recognition site,...

Figure 6 The template theophylline (T) is allowed to interact with the functional monomer methacrylic acid (M) to form a self-assembly. The monomers will interact with theophylline and will form a self-assembly complex mainly based on hydrogen bonding. This self-assembly and the positions of the functional monomers are then frozen and held in place by copolymerization with cross-linker ethyleneglycol dimethacrylate (L). This leads to a rigid polymer scaffold that retains the spatial conformation and thus the specific binding cavity of the original template. After extraction of the template, a molecularly imprinted polymer (MIP) is obtained and the imprinted cavity is able to specifically rebind the template and other, even similar structures are excluded from the binding site cavity.

Fig. 2.36 The coffee shrub and its berries, cocoa beans and tea flowers. Shown below are the 3D molecular models of caffeine, theobromine and theophylline. The difference between the chemical structures is the number and position of methyl groups (highlighted by dark shacMng). (Authors own work and copyright-free pictures from the book Bessette, Alan E., Chapman, William K. (eds.) Plants and flowers. 1761 Illustrations for artists and designers. Dover Publications, Inc., New York, 1992)...

Solute permeation experiments were performed using five representative solutes with different molecular weights and hydrodynamic sizes. The characteristics of selected solutes are listed in Table 6.3. In the experimental buffer solution in which pH was adjusted to 4 or 7, theophylline, vitamin BSA were in a neutral state, and riboflavin and cefazolin " showed ionized structures. 

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