Effect of the molecular size of carboxymethylcellulose and some polymers on the sustained release of theophylline from a hydrophilic matrix.

The objective of this study was to investigate the influence of the molecular size of carboxymethylcellulose (cmc) and some hydrophobic polymer additives on the release properties of theophylline from tablet matrices. The cmc matrices were prepared by the conventional wet granulation method. The granules were evaluated for angles of repose, bulk density, compressibility index, and porosity, while the tablets were subjected to hardness, friability and compression tests.

Bioavailability of metronidazole in rabbits after administration of a rectal suppository.

The bioavailability of metronidazole in rabbits was studied using plasma concentration measurements after the administration of the drug in a hydrophilic (glycerogelatin) suppository form. The peak in the plasma concentration time curve occurred about 1 hour after administration, indicating that the rate of absorption is fast and equivalent to that observed in humans after oral administration. There was rapid elimination of the drug, as indicated by a relatively high elimination rate constant and low plasma half-life.

Urinary excretion of rifampicin in the presence of ciprofloxacin.

To investigate the effect of the ciprofloxacin on the urinary excretion of the rifampicin in humans, ciprofloxacin and rifampicin were coadministered. Five healthy volunteers between the ages of 20 and 35 years received, on 2 separate occasions (phases 1 and 2) and at weekly intervals, 600 mg rifampicin and 600 mg plus 500 mg ciprofloxacin, respectively, with 350 mL of water. Urinary levels of rifampicin were measured from 1-72 hours later.

Effect of pefloxacin on the urinary excretion of rifampicin.

The effect of pefloxacin on the urinary excretion of rifampicin was investigated in 5 healthy volunteers between the ages of 20 and 35 years. The investigation was carried out in 2 different phases, with a 1-week drug washout separating the phases. Each subject received 600 mg rifampicin with 350 mL of water.

Salivary and urinary excretion and plasma-saliva concentration ratios of isoniazid in the presence of Co-administered ciprofloxacin.

Salivary and urinary excretion and plasma-saliva concentration ratios of isoniazid (INH) in the absence and presence of ciprofloxacin (CP) were investigated in healthy female volunteers. Results obtained indicated an absorption form of interaction between INH and CP. This led to delay in gastric emptying and onset of absorption of INH in the upper part of the gastrointestinal tract, resulting in a corresponding delay in the onset of salivary and urinary excretion of the drugs.