BACKGROUND Chitosan, a polymer derived from chitin, has been used for nasal drug delivery because of its biocompatibility, biodegradability and bioadhesiveness. Theophylline is a drug that reduces the inflammatory effects of allergic asthma but is difficult to administer at an appropriate dosage without causing adverse side effects. It was hypothesized that adsorption of theophylline to chitosa...

objective(s) in the present study, the differences in the relaxant effects of aqueous, ethyl acetate and n-butanol fractions of rosa damascena on tracheal smooth muscle of guinea pigs were examined. materials and methods the relaxant effects of three cumulative concentrations of each fraction (0.1, 0.2 and 0.4 g%) in comparison with saline and three cumulative concentrations of theophylline (0....

Theophylline poisoning generally occurs due to acute high dose intake as well as chronic intake of the medication. Toxicity symptoms can be seen with a plasma concentration of theophylline over 20 μg/ml. The consequences of theophylline toxicity include metabolic disturbances (hypokalemia, hyperglycemia, and metabolic acidosis), nausea, vomiting, and in severe cases seizures, cardiac arrhythmia...

1. Theophylline metabolism was studied using seven human cytochrome P-450 isoforms (CYPs), namely CYP1A1, 1A2, 2A6, 2B6, 2D6, 2E1 and 3A4, and microsomal epoxide hydroxylase (EH), expressed in human B-lymphoblastoid cell lines. 2. At a high theophylline concentration of 10 mM four CYPs (1A1, 1A2, 2D6, 2E1) catalyzed the metabolism of theophylline. 3. Theophylline had the highest affinity (appar...

Theophylline has been used for several decades in the treatment of asthma and remains the most widely prescribed anti-asthma drug worldwide, although the development of newer anti-asthma medications, especially inhaled steroids, has resulted in declining use of theophylline in industrialized countries. Theophylline is now considered to be a bronchodilator, but it is increasingly recognized that...

STUDY OBJECTIVE To determine the additive effect of oral theophylline in patients with stable COPD who received both inhaled salbutamol, 400 micrograms, and ipratropium bromide, 80 micrograms, four times daily administered with a metered-dose inhaler. DESIGN Twenty-four male patients with stable COPD (FEV1, 0.96 +/- 0.43 L; 36.8 +/- 17.0 percent predicted [% pred]) completed a randomized, dou...

Theophylline is a commonly used bronchodilator. However, due to its narrow therapeutic range, moderate elevation of serum concentration can result in adverse drug reactions (ADRs). ADRs occur because of interhuman pharmacokinetic variability and interactions with coprescribed medicines. We developed a physiologically based pharmacokinetic (PBPK) model of theophylline, caffeine, and ciprofloxaci...

Alkylxanthine drugs, such as theophylline, block adenosine receptors, inhibit phosphodiesterases and other enzymes, and cause the release of calcium from intracellular stores. Adenosine receptor blockade occurs at low micromolar concentrations of the drugs, while other effects occur in the millimolar concentration range. The effects of theophylline were tested on spontaneous transmitter release...

RNA aptamers are oligonucleotides that bind with high specificity and affinity to target ligands. In the absence of bound ligand, secondary structures of RNA aptamers are generally stable, but single-stranded and loop regions, including ligand binding sites, lack defined structures and exist as ensembles of conformations. For example, the well-characterized theophylline-binding aptamer forms a ...

A grand mal convulsion occurred in a patient with decompensated cor pulmonale. Although only modest doses of oral theophylline were being administered at the time of the convulsion the serum theophylline level was markedly raised and the theophylline clearance was very low. After treatment for cor pulmonale theophylline clearance improved; however, with the subsequent onset of fever and pneumon...