Rudy Schoenmaker

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In an open cross-over experiment, the influence of the antimicrobial agent co-trimoxazole on the single-dose pharmacokinetics of theophylline was studied in six healthy adults by comparing the pharmacokinetic parameters found after intravenous administration of theophylline without and with co-medication of co-trimoxazole for the previous 8 d. Theophylline(More)
The influence of the antibiotic drug doxycycline on steady-state pharmacokinetics of theophylline was studied in nine healthy adults by comparing the pharmacokinetic parameters measured during a 9-day course of theophylline alone and during comedication with doxycycline. Theophylline plasma concentrations were measured by means of high performance liquid(More)
The influence of time of drug administration on pharmacokinetics of theophylline was studied both after ingestion of a sustained-release tablet, containing choline theophyllinate ( Zy 15061-S. R.; Teovent ; Sabidal ; ZYMA S.A.) and after intravenous infusion of aminophylline to eight healthy volunteers. Both drugs were administered in the morning (10 a.m.)(More)
A single dose each of two brands of indometacin (INN; in some pharmacopoeias called indomethacin) containing suppositories, made with different vehicula , was administered rectally - in a cross over design - to ten healthy volunteers. Product A ( Dolcidium ) was made of a new waxy excipient which emulsifies at body temperature; product B was a leading brand(More)
A new rapid, selective and sensitive high pressure liquid chromatographic (HPLC) assay for indomethacin in plasma is described. The method involves precipitation of proteins with perchloric acid, followed by dichloromethane extraction using flurbiprofen as an internal standard. The organic solvent was evaporated and the residue dissolved in a water-methanol(More)
1 The in vitro characteristics (dissolution rate) of a sustained release theophylline preparation (Theo-Dur were first measured in acid medium (pH = 1) for 2 h and after that in a phosphate buffer (pH = 6.8) for 6 h. 2 The tablets released more than 95% of the active ingredient within 5 h at a rate of approximately 11% of the dose per hour at pH = 1 and(More)
A 41-year-old patient is described who was initially considered to be suffering from a space-occupying lesion in the posterior fossa. He was eventually found to be suffering from a megadolicho vascular malformation of the basilar artery, which caused a locked-in syndrome. The patient survived and improved considerably.
The systemic disposition of theophylline after taking a new, sustained release tablet (Theolair Retard 250 mg, Theolair S.R., Riker Laboratories) has been studied in 8 hospitalized patients. Absolute bioavailability was determined from the ratios of the areas under the serum concentration-time curves after intake of the tablet and after intravenous infusion(More)
The correlation between serum and saliva levels of theophylline was investigated in seven healthy volunteers after multiple dose administration of a low dose (300 mg/day) and a high dose (900 mg/day) of a sustained release theophylline preparation (Theo-Dur). Tablets were taken for five days, at 8 a. m. and 8 p. m. and a last dose was taken on Day 6 at 8 a.(More)
The influence of amoxycillin and theophylline on their mutual steady-state pharmacokinetics was studied in healthy adults by comparing the pharmacokinetic parameters as obtained during a 10-day course of each drug alone and after giving the drugs in combination. Amoxycillin and theophylline plasma concentrations were measured by means of HPLC methods. On(More)