An evaluation of the interaction of meloxicam with frusemide in patients with compensated chronic cardiac failure

AIMS

To evaluate the interaction of meloxicam with frusemide in patients with compensated cardiac failure.

METHODS

Nineteen patients with Grade II or III compensated chronic cardiac failure completed this randomized, double-blind, cross-over study. The patients received 40 mg frusemide day(-1) for 7 days. Thereafter, patients received either 15 mg meloxicam plus 40 mg frusemide day(-1), or one placebo tablet plus 40 mg frusemide day(-1) for 7 days. After a washout period of 7 days during which patients received 40 mg frusemide day(-1) for 7 days, the patients were crossed over to the alternate treatment. The effect of concomitant ingestion of meloxicam and frusemide on frusemide-induced diuresis, urine and serum electrolytes, urinary frusemide excretion, and plasma frusemide pharmacokinetics was also determined.

RESULTS

The estimate (90% confidence interval) of the '(frusemide + meloxicam)/(frusemide alone)' mean ratio of the variables Cmax, AUC(SS) and Cmax/AUC(SS) for plasma frusemide were 121% (101% to 145%), 106% (96.4% to 117%), and 114% (98.3% to 132%), respectively. Similarly, the estimate (90% confidence interval) of the '(frusemide + meloxicam)/(frusemide alone)' of the mean ratio of the variable cumulative urinary frusemide excretion after multiple doses of frusemide were 123% (101% to 150%) for the period 0-8 h, and 122% (105% to 142%) for the period 0-24 h after drug administration on day 7. The estimate (90% confidence interval) of the '(frusemide + meloxicam)/(frusemide alone)' mean ratio of the pharmacodynamic variables cumulative sodium excretion was 105% (95.2% to 116%) for the period 0-8 h and 108% (96.5% to 121%) for the period 0-24 h after drug administration on day 7.

CONCLUSIONS

Meloxicam may lead to slightly increased maximum concentrations of frusemide in plasma, as well as to slightly increased urinary excretion of frusemide, without affecting the pharmacodynamics of frusemide. Thus there is no clinically significant pharmacokinetic or pharmacodynamic interaction of meloxicam with frusemide following repeated co-administration of meloxicam and frusemide to patients with compensated chronic cardiac failure.

Pharmacokinetics of triptorelin after intravenous bolus administration in healthy males and in males with renal or hepatic insufficiency

AIMS

Triptorelin is a gonadotropin-releasing hormone (GnRH) analogue with enhanced affinity for GnRH receptors and a prolonged half-life due to its resistance to enzymatic degradation. The sustained-release formulation of this molecule is advantageous in conditions requiring chronic hormone suppression.

METHODS

This was an open study to determine the pharmacokinetics of a single i.v. bolus dose of 0.5 mg triptorelin acetate in four groups of six male subjects; namely in healthy subjects (Group I), in patients with varying degrees of renal insufficiency (Groups II and III), and in patients with hepatic insufficiency (Group IV).

RESULTS

The maximum concentrations of triptorelin were found to be similar for all four study groups (geometric mean Cmax between 41.6 mg ml(-1) and 53.9 mg ml(-1)). The total clearance of triptorelin decreased with increasing renal impairment, and was even lower in patients with hepatic insufficiency (geometric mean CLtot: 210 ml min(-1), 113 ml min(-1), 86.8 ml min(-1) and 57.3 ml min(-1) for Groups I, II, III and IV, respectively). Serum triptorelin concentrations in all four groups were adequately described by a three-compartment model. The elimination half-life for patients with hepatic impairment was similar to that of patients with renal impairment (geometric mean t(1/2, z): 6.6 h, 7.7 h and 7.6 h for Groups II, III and IV, respectively), but significantly longer than in healthy volunteers (2.8 h for Group I). The first and second distribution half-lives were similar for the four groups studied, with geometric mean distribution half-lives of about 0.1 h (6 min) and 0.75 h (45 min), respectively.

CONCLUSIONS

Although both renal and hepatic function are important for the clearance of triptorelin, the liver plays the predominant role in subjects suffering from some degree of renal impairment.

Endolymphatic sac tumor: a case report and review of the literature

BACKGROUND

Papillary tumors of the temporal bone are very rare but aggressive neoplasms. In the past, a middle-ear origin was presumed. Only recently convincing evidence exists that these tumors in fact arise from the endolymphatic sac.

METHODS

We present a case of an endolymphatic sac tumor (ELST) with detailed clinical, imaging, operative, and pathologic data. The literature on this rare tumor type is reviewed.

RESULTS

This 63-year-old woman had a progressive mass lesion in the temporal bone for a period of more than 35 years, resulting in unilateral fifth to eleventh cranial nerve palsy, progressive ataxia, and a pyramidal and pseudobulbar syndrome. Computerized tomography (CT) and magnetic resonance imaging (MRI) showed a tumor invading the pars squamosa and petrosa of the temporal bone, and extending into the middle and posterior fossa. Angiography demonstrated a hypervascular tumor mass. The patient underwent surgery, with nonradical removal of a tumor. Histologic examination demonstrated a papillary ELST. A search through the literature revealed 36 patients with ELST, based on convincing anatomic and histologic considerations.

CONCLUSIONS

It is important to make a distinction between ELST and the more benign middle-ear adenomas, since this leads to a different treatment and prognosis. ELST frequently invades the surrounding structures and extends intracranially. The treatment of choice is a radical resection, although complete resection is impossible in most of the cases. The value of adjunctive radiation therapy remains controversial.

Bioavailability of two selegiline hydrochloride tablet products

The bioavailability of two selegiline HCl (CAS 14611-52-0) tablet products was compared in a single-blind, single-dose, randomised, two-way, cross-over study with 25 healthy volunteers. A test preparation of selegiline HCl (4 x 5 mg tablets) was compared to a reference preparation of selegiline HCl (4 x 5 mg tablets). The volunteers were randomised receiving each treatment once. Two clinic days were separated by a wash-out period of between 6 and 14 days. The variable AUC(0-infinity) was the primary characteristic of the extent of formation (bioavailability) of the selegiline metabolites, desmethylselegiline and methamphetamine. For desmethylselegiline the point estimate (90% confidence interval) of the "test/reference" mean ratio for the variable Cmax is 98.4% (91.2% to 106%), for AUC(0-infinity) 103% (97.6% to 109%), and for Cmax/ AUC(0-infinity) 95.6% (89.4% to 102%). For methamphetamine the point estimate (90% confidence interval) of the "test/reference" mean ratio for the variable Cmax is 101% (96.8% to 105%), for AUC(0-infinity) 102% (95.3% to 109%), and for Cmax/AUC(0-infinity) 99.0% (91.5% to 107%). The results of this study indicate that the test preparation is bioequivalent to the reference preparation with respect to both the rate and extent of formation of desmethylselegiline and methamphetamine.

The efficacy of two bupivacaine hydrochloride injection products

OBJECTIVE

The relative efficacy of two bupivacaine hydrochloride injection products was investigated in patients who were undergoing intra-ocular eye surgery.

DESIGN

Patients took part in this double-blind, randomised, parallel-group study and received either Macaine (Keatings) or Regibloc (Intramed), according to the randomisation schedule.

SETTING

The study was carried out in the ophthalmology operating theatres of National and Pelonomi Hospitals, Bloemfontein, South Africa.

PATIENTS

Thirty male and 74 female patients who needed extra-capsular lens extraction plus intra-ocular lens implantation, extra-capsular lens extraction, or trabeculectomy were selected for the study.

OUTCOME MEASURES

Akinesia was evaluated after 10, 15 and 20 minutes. In the event of incomplete akinesia after 20 minutes, an additional injection was administered, and after 5 minutes another evaluation of akinesia was done. Anaesthesia was evaluated at the beginning of surgery.

RESULTS

The proportions of patients who received no additional anaesthesia were 57.7% for Macaine and 70.8% for Regibloc (difference 13.1%, 95% confidence interval (CI) -5.5 - 31.7%). The proportions of patients with adequate akinesia (possibly after additional anaesthesia) were 90.4% for Macaine and 89.6% for Regibloc (difference -0.8%, 95% CI-12.6 - 11.0%). The proportions of patients experiencing no pain or discomfort at the beginning of surgery were 88.2% for Macaine and 87.5% for Reglibloc (difference -0.7%, 95% CI-13.6 - 12.1%).

CONCLUSION

The study results indicate that Regibloc is at least as effective as, or superior to, Macaine in achieving adequate akinesia.

No influence of pantoprazole on the pharmacokinetics of phenytoin

Twenty-three healthy, male volunteers completed this doubleblind, randomized, placebo controlled, 2-period crossover study to assess the influence of multiple doses of pantoprazole on single-dose phenytoin pharmacokinetics. During each treatment period, the volunteers received either one 40 mg pantoprazole tablet or placebo for 7 days. In addition, a single-dose of 300 mg (3 x 100 mg capsules) phenytoin sodium was administered on day 4 of each treatment period. A 14-day wash-out period was allowed between phenytoin administrations. The results indicate that pantoprazole neither affects the rate nor the extent of absorption, nor the elimination of phenytoin.

Relative bioavailability of four clomipramine hydrochloride tablet products

The relative bioavailability of clomipramine was determined in two single-blind, single-dose, randomized, crossover studies. In the first study, the relative bioavailability of the test product, 2 x 25 mg clomipramine hydrochloride tablets (Noristan Ltd.), with respect to the reference product, Anafranil 2 x 25 mg tablets (clomipramine HCl; Ciba-Geigy (Pty) Ltd.) was determined. In the second study, the relative bioavailability of the test product, 5 x 10 mg clomipramine hydrochloride tablets (Noristan Ltd.), with respect to the reference product, Anafranil 5 x 10 mg tablets (clomipramine HCl; Ciba-Geigy (Pty) Ltd.), was determined. The geometric mean values for the variable Cmax were 31.3 ng mL-1 for the reference and 31.6 ng mL-1 for the test product in study 1. The geometric mean values for the variable AUC were 736 ng h mL-1 and 753 ng h mL-1 for the reference and test, respectively. In study 2, the geometric mean Cmax values were 25.8 ng mL-1 and 23.9 ng mL-1 for the reference and test respectively; the geometric mean AUC values were 569 ng h mL-1 and 547 ng h mL-1. The 90% confidence intervals for the 'test/reference' mean ratios of the plasma clomipramine pharmacokinetic variables Cmax and AUC(0-infinity) (as measures of the rate and extent of absorption of clomipramine, respectively) fall within the conventional bioequivalence range of 80-125% for both studies. The test products (clomipramine HCl) are therefore bioequivalent to the reference products (Anafranil) with respect to the rate and the extent of absorption of clomipramine in both 10 mg and 25 mg strengths.

Study of the effect of miglitol on the pharmacokinetics and pharmacodynamics of warfarin in healthy males

This was a double-blind, randomised, placebo-controlled, cross-over study to determine the possible pharmacodynamic and pharmacokinetic interaction of miglitol (CAS 72432-03-2, Bay m 1099) and warfarin sodium (CAS 129-06-6) in healthy volunteers. The study comprised 2 treatment periods of 8 days each, with a medication-free period of 14 days between the 2 treatment periods. The volunteers received medication for 7 days and were assessed over 8 days in both treatment periods. According to the randomisation, the volunteers received either 100 mg of miglitol or matching placebo, 3 times daily during the treatment periods. On Day 4 of each treatment period the volunteers received a single oral dose of 25 mg warfarin sodium together with miglitol or placebo. The effect of miglitol on both the pharmacokinetics and pharmacodynamics (prothrombin time and clotting factor VII activity) of warfarin sodium was investigated. The study results indicate that the concomitant administration of miglitol and warfarin does not affect the pharmacokinetics of R- and S-warfarin, or the pharmacodynamics of warfarin.

Relative bioavailability of rifampicin, isoniazid and ethambutol from a combination tablet vs. concomitant administration of a capsule containing rifampicin and a tablet containing isoniazid and ethambutol

Twenty male volunteers who were slow metabolisers of isoniazid, completed this single-blind, single-dose, randomised, cross-over study to compare the bioavailability of rifampicin (CAS 13292-46-1), isoniazid (CAS 54-85-3) and ethambutol (CAS 1070-11-7) from Myrin tablets (test preparation) with the bioavailability of these drugs from a combination of capsules containing rifampicin and tablets containing isoniazid and ethambutol (reference). There were 2 treatment periods and on clinic days volunteers were given either the reference (300 mig rifampicin plus 200 mg isoniazid and 600 mg ethambutol HCl), or the test preparation (300 mg rifampicin, 150 mg isoniazid and 600 mg ethambutol HCl). Serial blood samples were drawn from the volunteers and rifampicin, isoniazid and ethambutol assays were performed. The results of this study indicate that the test preparation is equivalent to the reference with respect to both the rate and the extent of absorption of rifampicin, isoniazid (after adjustment for the different doses of isoniazid and ethambutol).

Influence of meloxicam on furosemide pharmacokinetics and pharmacodynamics in healthy volunteers

Fifteen healthy male volunteers participated in an open, multiple-dose study to investigate a possible interaction between furosemide and meloxicam, a new non-steroidal anti-inflammatory agent (NSAID). The study comprised three treatment periods. First, furosemide (40 mg) was administered as a single oral daily dose for 3 days. A wash-out day was followed by the administration of meloxicam (15 mg) as a single oral daily dose for 10 days. Thereafter, meloxicam and furosemide were administered concomitantly at the same doses as described above, for 3 days. The effect of concomitant ingestion of meloxicam and furosemide on furosemide-induced diuresis, urine and serum electrolytes, and furosemide pharmacokinetics was determined, after both single and repeated administration of furosemide. Estimates of the "(furosemide+meloxicam)/(furosemide alone)" mean ratio of the variable AUC(0-infinity) for plasma furosemide and the cumulative sodium excretion (0-8 h) were 97.4% (90% confidence interval 89.7-106%) and 88% (90% confidence interval 82-94%), respectively. The study results indicate that meloxicam does not affect the pharmacokinetics of furosemide in healthy volunteers, nor does it affect furosemide-induced diuresis or serum electrolytes. The cumulative urinary electrolyte excretion after concomitant administration of meloxicam and furosemide is somewhat lower than after administration of furosemide alone, in particular for the period 0-8 h after administration of furosemide. This effect of meloxicam on furosemide dynamics is small, and is probably not clinically relevant in healthy volunteers under the dosing regime studied.

Lack of effect of pantoprazole on the pharmacodynamics and pharmacokinetics of warfarin

Twenty-six healthy males took part in this double-blind, randomised, placebo-controlled, two-period, cross-over study. Pantoprazole (40 mg) (test) or placebo (reference) were administered once daily, for 8 days, with a 3 week washout period. A single oral dose of 25 mg warfarin sodium was co-administered with pantoprazole or placebo on Day 2 of each treatment period. The 90% confidence intervals for the 'test/reference' mean ratios of the excess AUC(0.168 h) of prothrombin time and AUC(0.168 h) of factor VII, and of Cmax, AUC and t1/2 of both R- and S-warfarin fell within the equivalence range of 80% to 125%. These results suggest that pantoprazole does not alter the pharmacokinetics or pharmacodynamics of warfarin.

No influence of pantoprazole on the pharmacokinetics of phenytoin

Twenty-three healthy, male volunteers completed this doubleblind, randomized, placebo controlled, 2-period crossover study to assess the influence of multiple doses of pantoprazole on single-dose phenytoin pharmacokinetics. During each treatment period, the volunteers received either one 40 mg pantoprazole tablet or placebo for 7 days. In addition, a single-dose of 300 mg (3 x 100 mg capsules) phenytoin sodium was administered on day 4 of each treatment period. A 14-day wash-out period was allowed between phenytoin administrations. The results indicate that pantoprazole neither affects the rate nor the extent of absorption, nor the elimination of phenytoin.

No pharmacokinetic or pharmacodynamic interaction between rivastatin and warfarin

Twenty-one healthy, male volunteers completed this double-blind, randomized, two-period, crossover study to determine the possible pharmacodynamic and pharmacokinetic interaction of the concomitant administration of rivastatin and warfarin sodium in healthy volunteers. The study comprised 2 treatment periods of 8 days each, with a medication-free period of 14 days between the 2 treatment periods. According to the randomization, the volunteers received either 300 micrograms of rivastatin or matching placebo once daily during the treatment periods. On day 4 of each treatment period, the volunteers also received a single oral dose of 25 mg of warfarin sodium together with rivastatin or matching placebo. The effect of rivastatin on both the pharmacokinetics and pharmacodynamics (prothrombin time and clotting factor VII activity) of warfarin sodium, and the effect of warfarin sodium on the pharmacokinetics of rivastatin were investigated. Blood sample assays included the analysis of both R- and S-warfarin, because it is known that the enantiomers differ in anticoagulant potency. The study results indicate that the concomitant administration of rivastatin and warfarin does not affect the pharmacokinetics of R- and S-warfarin, or the pharmacodynamics of warfarin. Furthermore, the administration of warfarin sodium does not affect the pharmacokinetics of rivastatin.

Absolute bioavailability of a new high dose methylprednisolone tablet formulation

This was a single-blind, single-dose, randomized crossover study to determine the absolute bioavailability of Medrol, a new high dose (100 mg) methylprednisolone tablet product, by comparing it with 100 mg methylprednisolone from an intravenous formulation, Solu-Medrol. Fourteen healthy, non-smoking, Caucasian male volunteers took part. On treatment days volunteers remained recumbent for 4 hours after drug administration, with food and fluid intake standardized over this period. Serial blood samples were drawn over a 14-hour period after drug administration. Plasma methylprednisolone concentrations were determined by high performance liquid chromatography. The geometric means of AUCi.v. and AUCtablet were 4,049 and 3,334 ng.h/ml, respectively. The absolute bioavailability of the tablet product was 82%, which is in agreement with published data for other oral dosage forms of methylprednisolone. Volunteers displayed the expected rise in peripheral blood neutrophil count, but no other clinically relevant changes in hematology or clinical chemistry were observed. No adverse drug reactions were recorded. It is concluded that the tablet product can be used as a substitute for parenteral methylprednisolone in situations requiring high-dose therapy.

Relative bioavailability of four controlled-release nifedipine products

Four controlled-release nifedipine products were investigated in two clinical studies. In study 1, 22 healthy male volunteers took part in an open, multiple-dose, randomized, crossover study to determine the relative bioavailability of two 10 mg controlled-release nifedipine tablets (Adalat Retard, Bayer), administered 12 hourly, and one 20 mg controlled-release nifedipine tablet (Adalat Retard, Bayer) administered 12 hourly. In study 2, 24 healthy male volunteers took part in an open, multiple-dose, randomized, three-period, crossover study to determine the relative bioavailability of (i) two 30 mg nifedipine gastro-intestinal therapeutic system (GITS) tablets (Adalat XL, Bayer) administered once daily; (ii) one 60 mg nifedipine GITS tablet (Adalat XL, Bayer) administered once daily; and (iii) one 20 mg plus one 10 mg nifedipine controlled-release tablet (Adalat Retard, Bayer), administered 12 hourly. In both studies detailed pharmacokinetic data, in particular with respect to the controlled-release characteristics of the different formulations, were collected. Results of both studies indicate that all nifedipine products investigated are bioequivalent with respect to the extent of absorption of nifedipine. The nifedipine GITS products (Adalat XL) have better controlled-release properties than the Adalat Retard product, and are suitable for once-a-day administration.

Steady-state pharmacokinetics of phentermine extended-release capsules

Twenty-one healthy, caucasian, male volunteers completed this randomized single blind, multiple-dose, crossover bioavailability study during which either phentermine HCl capsules (Minobese Forte, reference product) or phentermine base capsules (Duromine, test product) were ingested once daily for 14 days. A washout period of 14 days was allowed between the two treatment phases. On profile days (day 14 of each treatment phase) subjects remained recumbent for 24 hours after drug administration. Serial venous blood samples were drawn over the 24 hour dosing interval for plasma phentermine assay by gas chromatography. The 90% confidence intervals for the "test/reference" mean ratios of the pharmacokinetic variables Cmax,norm, Cmin,norm, AUCnorm (normalized for difference in the dose of phentermine base), %PTF and T75% Cmax, all fell within the bioequivalence range of 80% to 125%. With the aid of trough plasma phentermine concentrations, it was established that steady-state was reached after 14 days of once daily administration of either product. Adverse events experienced on both treatments included prolonged or recurrent episodes of insomnia, nausea, headache, dry mouth and dizziness. No clinically relevant changes in clinical chemistry or hematology variables occurred during the study.

The effect of benzbromarone on allopurinol/oxypurinol kinetics in patients with gout

The objectives of this study were to establish if, and to what extent, benzbromarone affects allopurinol/oxypurinol kinetics, and to compare the uric acid lowering capabilities of Allomaron (allopurinol 100 mg plus benzbromarone 20 mg) with the effects of allopurinol alone in patients with confirmed gout. We studied 14 adult men in an open randomized cross-over study. After a 14 day run-in period with Zyloprim (2 x 100 mg allopurinol tablets in the morning), the patients were randomly allocated to morning doses of either Allomaron (2 tablets) or Zyloprim (2 tablets). Seven days later cross-over was effected and the alternative treatment was taken for a further 7 days. On days 7 and 14 the patients came into hospital and venous blood samples were taken over 24 h for allopurinol and oxypurinol assays by HPLC. Serum uric acid was determined on days -14, 1, 7, and 14. Benzbromarone lowered plasma oxypurinol concentrations (Allomaron/Zyloprim mean ratio of AUC0-->24 was 59%; 95% confidence interval 54-64%), but did not affect plasma allopurinol concentrations. Despite this pharmacokinetic interaction of benzbromarone with allopurinol, resulting in lower plasma concentrations of oxypurinol, Allomaron was superior to allopurinol alone in lowering serum uric acid, probably because of the added uricosuric effect of benzbromarone.

Attenuation of cutaneous reactivity to histamine by cetirizine and dexchlorpheniramine

A double-blind cross-over study was performed in 12 healthy female volunteers comparing cetirizine di-HCl (10 mg) and sustained release dexchlorpheniramine maleate (6 mg) with respect to attentuation of histamine-induced skin wheals and subjective central nervous system (CNS) effects. Cetirizine was significantly more effective than dexchlorpheniramine in suppressing the size of wheals from 2 to 24 h after drug administration. In fact, at 24 h cetirizine was still as effective as 2 h after ingestion. Ten subjects receiving dexchlorpheniramine reported subjective symptoms relating to CNS depression, in contrast to only one subject given cetirizine.

Comparative bio-availability of theophylline whole and halved sustained-release tablets

In a randomised, multiple-dose, cross-over study in 14 healthy volunteers, plasma theophylline concentrations were compared during a 12-hour dosing interval after repeated administration of theophylline (Euphyllin Retard; Byk Gulden) as whole and halved tablets. Bio-availability of theophylline from the halved tablets relative to the whole tablets was: 116% (100%, 134%) for the extent of absorption as judged by the area under the concentration time curve (AUC) and 115% (99%, 135%) for the rate of absorption as judged by maximum concentration (Cmax). The confidence levels for the 80-120% bio-equivalence range were 72% (AUC) and 76% (Cmax), those for the 80 and 125% range were 91% (AUC) and 91% (Cmax). The plateau times T75% Cmax, which characterise the sustained-released properties, were 8.5 +/- 2.9 hours (halved) and 8.3 +/- 2.5 hours (whole) during the 12-hour dosing interval. It is concluded that no clinically relevant deviations in steady-state plasma theophylline concentration and sustained-release properties are likely to result from breaking (halving) the film-coated tablets.

Pharmacokinetics of temazepam after day-time and night-time oral administration

The pharmacokinetic disposition of temazepam was compared after a day-time and night-time dose in an open randomised crossover study. Twelve healthy male volunteers received a single oral dose of 20 mg temazepam in a soft gelatine capsule at 0900 h or 2200 h. Blood samples were taken immediately before dosing and at selected times over the 36-h period after each dose. The absorption of temazepam was slower after evening administration; the absorption half-life and time to reach maximal plasma concentration being 0.53 h and 1.67 h respectively, compared to 0.38 h and 1.02 h following morning administration. Considering distribution characteristics, evening administration produced a lower peak plasma temazepam concentration (362 ng/ml) compared with a day-time level of 510 ng/ml. Distribution half-life after night-time administration was increased compared with day-time administration (1.76 h vs 1.03 h). A significantly higher percentage of the drug, relative to Cmax, remained in the plasma at 8 and 24 h after evening dosing (39.3 and 15.4% compared to 24.7 and 11.2% following day-time administration). In spite of the half-lives of absorption, distribution and elimination all being longer after the evening dose, the overall bioavailability, as measured by the area under the curve (AUC) was comparable after the two times of administration. Similarly the difference in the mean residence time (MRT) of the two doses was within accepted limits. It is concluded that a chronopharmacokinetic effect was seen for temazepam; however it is unlikely to be of any clinical significance.

Ibuprofen bio-availability. A comparison of Brufen and Inza

Ibuprofen in the form of Brufen 200 mg tablets and Inza 200 mg and 400 mg tablets was administered to 18 healthy adult volunteers (9 men and 9 women) in a single-dose (800 mg ibuprofen) open randomized cross-over bio-availability study. Tests revealed increased time required for 50% dissolution to take place for Inza tablets (40-47 minutes) relative to Brufen tablets (7 minutes). Maximum concentration and time to maximum concentration differed significantly (over 20%) between Inza and Brufen, being approximately 30% lower and 67% greater respectively in the case of Inza tablets. Area under plasma concentration time curves were comparable. These data suggest that the Inza tablets tested are not bioequivalent to Brufen 200 mg tablets. Clinical implications are discussed.

The microbial metabolism of condensed (+)-catechins by rat-caecal microflora

The metabolism of 2,3-trans-3,4-trans-3,5,7,3',4'-pentahydroxy-4-(2,4,6-trihydrox yphenyl)-flavan and 2,3-trans-3,4-trans-3,5,7,3',4',-pentahydroxy-4-(2,3-trans-3,5,7,3 ', 4'-pentahydroxyflavanyl-[8])-flavan in vitro by rat-caecal microflora was investigated. Metabolites were extracted and enriched by column chromatography and preparative h.p.l.c., while structural determination was carried out using comparative g.l.c.-mass spectrometry and p.m.r. spectrometry. The metabolites identified were derivatives of benzoic acid, phenylacetic acid, phenylpropionic acid and phenyllactic acid in addition to phloroglucinol, delta-(3-hydroxyphenyl)-gamma-valerolactone and 1-(3-hydroxyphenyl)-3-(2,4,6-trihydroxyphenyl)-propan-2-ol. An additional metabolic route, which differs from the expected severance of the (+)-catechin-phloroglucinol bond and well-documented total heterocyclic ring degradation of flavanoids, is proposed.

Isolation of the intermediate filament protein vimentin by chromatofocusing

A novel, simple and relatively rapid method is described for the isolation of the intermediate-sized filament protein vimentin from eye lens tissue. Chromatofocusing is applied as the sole purification step. The apparent isoelectric point of the protein in 6 M urea and at 22 degrees C is 4.9. Electrophoretic mobility on one- and two-dimensional polyacrylamide gels, solubility in 6 M urea and amino acid composition were used for identification.

The microbial metabolism of (+)-catechin to two novel diarylpropan-2-ol metabolites in vitro

The metabolism of (+)-catechin by rat-caecal microflora in vitro was investigated. Metabolites were isolated by column chromatography, preparative t.l.c. and h.p.l.c., while structural allocation was aided by mass spectrometry and proton magnetic resonance. In contrast with the well-documented total heterocyclic ring cleavage of flavanoids, (+)-catechin was found to undergo partial heterocyclic ring cleavage of two novel diarylpropan-2-ol metabolites. p-Dehydroxylation of (+)-catechin predominates during its degradation to the diarylpropanol metabolites.

Large-scale preparation of gamma-crystallin and fractionation by chromatofocusing

Large quantities of calf gamma-crystallin can be prepared by a single and rapid salting-out procedure. The final product is indistinguishable from the gamma-crystallin fraction obtained after gel filtration of a 15000 g lens protein supernatant over Sephadex G 200. Further fractionation is achieved by the mild procedure of chromatofocusing yielding six to eight subfractions. The latter have been characterized by polyacrylamide gel electrophoresis (PAGE) in 6 M-urea, SDS-gel electrophoresis, partial digestion with Staphylococcus aureus protease and amino acid analysis.