Evaluation of the food effect on a drospirenone only contraceptive containing 4 mg administered with and without high-fat breakfast in a randomised trial

Background

The objective of the present trial was to assess the difference in pharmacokinetics (PK) of an oral test preparation containing 4 mg drospirenone (DRSP) under fasting conditions compared to PK upon food intake after single dose administration.

Methods

Open label, single centre, two-treatment, two-sequence, crossover study in 24 healthy female volunteers, with duration of 1 day per sequence and with a real wash-out period of 14 days to investigate the relative bioavailability of DRSP with both forms of administration. The 90% confidence intervals (CI) were calculated for the intra-individual ratio (test with food vs. without food) of the PK endpoints Area under the curve; 0–72 h [AUC(0-72 h₎] and maximal plasma concentration [Cmax] of DRSP.

Results

The 90% CI calculated by analysis of variance using logistic transformation (ANOVA-log) for the endpoint, intra-individual ratio (Test ‘A’ = with food intake) vs. Test ‘B’ = without food intake) of AUC(0-72 h) of drospirenone was between 104.72 and 111.36%. The 90% CI calculated by means of ANOVA- log for the endpoint intra-individual ratio (Test ‘A’ vs. Test ‘B’) of Cmax of DRSP was between 118.58 and 141.10%. The mean relative bioavailability of the test with food ‘A’ compared to the Test without food ‘B’ after single dose administration based on the endpoints AUC(0-72 h₎ was 107.99%; for the endpoint Cmax it was 129.35%.

Conclusions

The rate of absorption, based on the endpoint Cmax of DRSP was increased by about 30% under fed conditions. With respect to consumer habits, this may represent a relevant benefit for contraceptive safety, as the time span between food consumption and pill intake does not play a role.

Implications

Our results suggest that the food intake has no impact on the absorption of 4 mg DRSP in the management of contraception. This increases the contraceptive efficacy as no interference with food is expected when consuming the oral formulation under real life conditions.

Trail registration: Trial registration number: EudraCT-No: 2012–004,309-28.

Safety, influence on the endometrium, sonographic changes and bleeding profile after 13 cycles with the new drospirenone only pill (DOP) for contraception

Background

The primary objective of the present trial was to assess the endometrial safety of a new oral contraceptive containing 4 mg drospirenone for a total duration of 13 cycles of 28 days each: 24 days of active treatment followed by 4 days placebo treatment per treatment cycle.

Materials and methods

This was a single-center, open-label, multiple-dose study on healthy female subjects at risk of pregnancy. Twenty one (= safety population set) pre-menopausal female Caucasian subjects started treatment with the study medication. The mean age was 29.0 years (range 19.0–36.0 years). Four subjects terminated the trial prematurely for the following reasons: on the subject’s request (n=2), due to an adverse event (n=1) and due to loss of contact (n=1). Seventeen subjects completed the planned duration of 13 cycles of open treatment with the test product (each cycle of 28 days).

Results

At visit 1 (pre-treatment), the biopsy result in the safety population set was proliferative in 14 cases and secretory in seven cases. At visit 7, four cases showed an inadequate result (insufficient tissue for diagnosis), 12 as proliferative and three as secretory. The number of biopsies with proliferative and secretory results reduced under treatment (safety population). The pre-post treatment changes in the endometrial biopsy results in the treatment completers set (n=17) showed almost no differences. At visit 1 (pre-treatment), the biopsy result was proliferative in 12 cases and secretory in five cases. At visit 7 (after 13 cycles of 28 days), four cases showed an inadequate result (insufficient tissue for diagnosis), 11 as proliferative, and two as secretory. The mean endometrial thickness in the safety population was reduced from 8.3 mm at visit 1 to 6.0 mm at visit 7. When comparing the endometrial thickness in the 21 subjects (safety population), the endometrial thickness showed a pre-post difference of 2.1 mm, whereas the endometrial thickness in the 17 study completers showed a pre-post difference of 2.5 mm (8.2 mm at visit 1–5.6 mm at visit 7).

Conclusions

Drospirenone 4 mg film-coated tablet in a dosage regime of 24/4 days is, regarding endometrial histology, a safe drug. Trial registration: EudraCT Register number: 2013-002300-13.

Comparative pharmacokinetic estimates of drospirenone alone and in combination with ethinyl estradiol after single and repeated oral administration in healthy females

OBJECTIVE

To determine the pharmacokinetics (PK) of drospirenone (DRSP), alone versus in combination with ethinyl estradiol (EE), after single and repeated administration.

STUDY DESIGN

We conducted a single-centre, open-label, crossover, 2-treatment, 2-period, 2-sequence study in which non-micronized DRSP 4 mg or a combination of DRSP 3 mg and EE 0.02 mg were administered to healthy female subjects on day 1 to obtain a single-dose kinetic profile, and from day 4 to day 15 to obtain a repeated-dose kinetic profile. The maximum observed concentration (C_max) and area under the concentration/time curve (AUC) were determined in a model-independent way using non dose corrected data. Statistical analysis was based on a parametric method (ANOVA-log).

RESULTS

A total of 24 healthy female subjects were randomized 1:1 into the study. The mean relative, non-dose-corrected PK estimates after single-dose administration for the endpoints AUC_(0-72h), AUC_(0-24h) and C_max were 543.5 ng*h/mL, 296.1 ng*h/mL and 27.3 ng/mL for DRSP alone, and 442.0 ng*h/mL, 264.7 ng*h/mL and 37.5 ng/mL for the DRSP/EE combination; p < 0.001. The mean relative, non-dose-corrected PK estimates after repeated dose administration for the endpoints AUC_(0-72h), AUC_(0-24h) and C_max were 1066.8 ng*h/ml, 570.2 ng*h/mL and 41.0 ng/mL for DRSP alone, and 1394.5 ng*h/mL, 732.8 ng*h/mL and 61.4 ng/mL for the DRSP/EE combination; p < 0.001.

CONCLUSIONS

DRSP alone exhibits a lower accumulation ratio than together with EE. The extent of systemic exposure at steady-state is about 32% less with the new formulation (AUC_(0-24h), steady-state geometric mean ratio: 77.8%; 90% confidence interval: 74.6%-81.1%). This PK profile may be caused by EE.

IMPLICATIONS

Our results suggest that metabolic pathways of DRSP can be inhibited by EE resulting in higher DRSP plasma concentrations in DRSP/EE formulations than in a DRSP-alone formulation. The enzymes CYP3A4 and SULT1A1 may play a role. Additional drug-drug-interaction studies are needed to better understand these metabolic pathways and their future clinical implications.

Serotonin Reuptake Inhibitors: Bioequivalence of Sertraline Capsules

The study was designed to evaluate the bioavailability of two sertraline (CAS 79617-96-2) formulations. A bioequivalence study was carried out in 24 healthy male volunteers, who were administered 50 mg capsules of the test formulation (Seralin) and the originator product (reference) as a single dose. The trial was performed according to an open, randomized, cross-over design with a washout period of 14-20 days in one study center. Blood samples were taken up to 96 h post dose, the plasma was separated and the concentrations of sertraline were determined by HPLC-MS-MS. The mean Cmax were 9.01 +/- 2.26 ng/mL and 8.24 +/- 2.14 ng/mL, while the mean AUC0-t were 259.09 +/- 105.36 ng x h/mL and 234.36 +/- 95.18 ng x h/mL for the test and reference formulations, respectively. The mean AUC0-inf were 292.66 +/- 128.09 ng x h/mL (test) and 267.23 +/- 116.40 ng x h/ mL (reference). The mean tmax was 5.88 +/- 1.03 h for the test capsules and 6.17 +/- 1.66 h for the reference formula. The mean t1/2el was 26.49 +/- 6.45 h for the test formulation and 26.23 +/- 6.64 h for the reference formulation. Mean MRT values for the test and reference formulations were 28.14 +/- 5.37 h and 27.81 +/- 5.13 h, respectively. No significant differences of pharmacokinetic parameters between the two studied formulations were found. The 90% confidence interval for the primary target parameters, intra-individual ratios of AUC0-t and Cmax of sertraline were between 1.03 and 1.19 (AUC0-t) as well as between 1.02 and 1.17 (Cmax) and thus within the acceptance ranges for bioequivalence trials. Concerning the secondary parameter tmax the 90% confidence interval for the intra-individual differences was between -1.00 and 0.50 h. In the light of the present study it can be concluded that sertraline test capsules are bioequivalent to the reference formulation.

Enhanced Plasma Concentration by Selective Deuteration of Rofecoxib in Rats

The plasma concentrations of BDD-11602 (4-[4- (methanesulfonyl)phenyl]-3-(pentadeuterophenyl)-5H-furan-2-one), a rofecoxib derivative in which the positions 2',3;4',5' and 6' of the phenyl ring were deuterated, and rofecoxib (4-(4-methylsulfonylphenyl)-3-phenyl-5H-furan-2-one, CAS 162011-90-7) were compared in order to explore the effects of selective deuteration on the systemic availability. The COX-2 selectivity in vitro was also compared. Following oral gavage administration of 0.1, 1 or 10 mg/kg BDD-11602 to Sprague Dawley rats, AUCo-t, (area under the curve) and Cmax (maximum concentration) values were statistically significant higher than those of rofecoxib at the same doses. The overall increase in AUC0-t and Cmax for BDD-11602 over rofecoxib was 1.53-fold and 1.60-fold, respectively. BDD-11602 and rofecoxib inhibited COX-2-derived PGE(2) synthesis with IC50 values of 173 nmol/l and 169 nmol/l, respectively. IC50 values for inhibition of human platelet COX-1 were estimated to be above 1 micromol/l for both compounds. The substitution of hydrogen by deuterium on the positions 2: 3',4',5' and 6' in BDD-11602 leads to superior oral availability compared to the non-deuterated compound, whereas the COX-2 selectivity is not affected.

Pharmacodynamic equivalence study of two preparations of eye drops containing dorzolamide and timolol in healthy volunteers

OBJECTIVE

The aim of the present study was to assess the pharmacodynamic equivalence (lowering of intraocular pressure) of two preparations of eye drops containing 20 mg dorzolamide (CAS 120279-96-1) and 5 mg timolol (CAS 26839-75-8).

METHOD

The study was conducted as a monocentric, observer-blinded, randomized, single-dose, two-period crossover study in 38 healthy volunteers. Each volunteer received on day 1 in each period in a random way a single dose of 1 drop of the test or the reference formulation in the conjunctival sac of the right eye separated by a wash-out period of 7 days. Measurement of intraocular pressure (IOP) of the right eye (by a blinded observer) was performed on day 1 of each study period pre-dose and 2 h post dosing by means of Goldmann applanation tonometry. In order to investigate the pharmacodynamic equivalence of both products, the two-sided 95% confidence interval was calculated for the difference of the primary target parameter (absolute decrease in IOP 2 h post dose), by means of a parametric (ANOVA) statistical method.

RESULTS

The results of the statistical evaluation of the primary target parameter "absolute decrease in IOP 2 h post dose" demonstrated a decrease in the IOP of 4.72 mmHg for the eye treated with the test formulation (dorzolamide 20 mg/ml + timolol 5 mg/ml eye drops) and 4.61 mmHg for the treated with the reference formulation. The mean difference was 0.11 mmHg. The 95% confidence interval was between -0.33 and 0.55 mmHg and thus entirely within the pre-defined equivalence range (+/- 1.5 mmHg). The results of the statistical evaluation of the secondary target parameter relative (as % of baseline) decrease in IOP 2 h post dose demonstrated essentially similar effectiveness in lowering the IOP by 27.63% (test formulation) and 27.12% (reference formulation), respectively. Both drug products were well tolerated.

CONCLUSION

Both formulations showed comparable results obtained at a time probably equal to the maximum effect concerning the primary target parameter lowering of IOP 2 h post dose. The safety profile of both preparations showed no difference.

Influence of acarbose on blood glucose and breath hydrogen after carbohydrate load with sucrose or starch

A monocentric, open, randomised, single-dose, six-period crossover trial was carried out in healthy volunteers under fasting conditions to establish the most appropriate study design for a pivotal bioequivalence trial with acarbose (CAS 56180-94-0) regarding a) dosage of the drug, b) type of carbohydrate load, c) type of primary endpoint, and d) sample size. 50 g sucrose or 50 g starch were used as carbohydrate load. Acarbose was administered in doses of 50 and 200 mg. Blood glucose and breath hydrogen were evaluated as endpoints. Both acarbose doses reduced the effect of carbohydrate load. Blood glucose: no statistically significant difference could be noted between the overall effect of 50 mg and that of 200 mg acarbose irrespective of the type of carbohydrate load. Breath hydrogen: an influence could be shown only for sucrose as carbohydrate load. Practically no effect was observed with starch. The overall increase of effect is by more than 200% with sucrose when the dose of acarbose increases from 50 to 200 mg. This difference between the effects of both doses of acarbose on breath hydrogen is statistically significant. For a pivotal trial, sucrose is the most appropriate type of carbohydrate load, baseline adjusted area under the breath hydrogen response is the most appropriate primary endpoint, and a dose of 100 mg acarbose is the most appropriate dosage. A total number of 100 subjects will be needed for proving pharmacodynamic equivalence between two acarbose products in a pivotal trial.

Therapeutic effects of epoetin zeta in the treatment of chemotherapy-induced anaemia

OBJECTIVE

To perform an open, non-controlled, multiple-dose, international, multicentre, phase III study to evaluate epoetin zeta, a biosimilar epoetin referenced to epoetin alfa, for the treatment of chemotherapy-induced anaemia in patients with cancer.

METHODS

Safety, tolerability and efficacy of subcutaneously administered epoetin zeta were assessed in 216 patients with solid tumours or non-myeloid haematological malignancies receiving chemotherapy and at risk of transfusion.

RESULTS

A significant (p < 0.0001) increase in mean haemoglobin (Hb) level (1.8 g/dL) was observed between baseline and week 12 (intent-to-treat population); 176/216 (81.5%) patients achieved a response (increase in Hb > or = 1 g/dL or reticulocyte count > or = 40,000 cells/microL) by week 8. Over the treatment period, 231 treatment-emergent adverse events were experienced by 91 patients; 9/216 (4.2%) experienced a clinically significant thrombotic event within the first 12 weeks of epoetin zeta treatment, significantly lower than the assumed 18% baseline incidence (p < 0.0001) based on historical data from epoetin trials. No transfusion was necessary for 175/216 patients (81.0%) and quality of life improved over the study. No patients developed anti-erythropoietin antibodies. Sponsor trial no: CT-830-05-0009.

CONCLUSION

This study demonstrates that subcutaneously administered epoetin zeta is well-tolerated and has efficacy in the treatment of anaemia in patients with cancer receiving chemotherapy and at risk of transfusion.

Bioequivalence study of two different clopidogrel bisulfate film-coated tablets

OBJECTIVE

The aim of the present study was to evaluate the bioequivalence of two oral clopidogrel (CAS 113665-84-2) formulations.

METHOD

The study was conducted as a monocentric, open, randomized, single-dose, two-period crossover trial in 48 healthy volunteers with a duration of hospitalization of approximately 24 h after dosing on day 1 and with a real wash-out period of 7 days. Blood samples were collected for 24 h post dosing in each period. The plasma was separated and the concentrations of clopidogrel were determined by a LC-MS/MS method. AUC(0-tlast), Cmax, tmax, AUC(0-inf), MRT and t1/2 were calculated for both formulations.

RESULTS

The arithmetic means of AUC(0-tlast) and Cmax were 3,656.01 pg x h/ml and 1970.22 pg/ml for the test formulation and 3771.51 pg x h/ml and 1756.52 pg/ml, respectively, for the reference formulation. The mean tmax was 1.16 h for the test and 1.13 h for the reference formulation. The point estimators of the ratios of the test and reference formulations for AUC(0-tlast) and Cmax were 1.042 and 1.115, respectively. Furthermore, the 90% confidence intervals calculated by means of ANOVA-log for the first primary endpoint of the trial, the intra-individual ratio (T/R) of AUC(0-tlast) of clopidogrel was between 0.932 and 1.165. The 90% confidence interval calculated by means of ANOVA-log for Cmax of clopidogrel was between 0.973 and 1.277. The 90% confidence intervals for both parameters were within the predefined acceptance ranges (0.80-1.25 for AUC(0-tlast) and 0.75-1.33 for Cmax). The intraindividual coefficients of variation determined by means of ANOVA-log were 33.51% for AUC(0-tlast) and 41.29% for Cmax.

CONCLUSION

While both products were bioequivalent in terms of the rate and extent of absorption, the present study also confirmed a high variability for clopidogrel suggesting high volunteer numbers in bioequivalence trials.

Effect of epoetin zeta for correction of renal anemia in hemodialysis patients with thalassemia minor

Two patients with thalassemia minor and end-stage renal failure on hemodialysis were treated with epoetin zeta (Silapo, Retacrit; STADA, Germany), a medicinal product that was developed and registered as biosimilar to epoetin alfa. Dosing was titrated individually for two patients to achieve a stable hemoglobin (Hb) concentration of 10.5-12.0 g/dL. One patient was treated intravenously with epoetin zeta; the other patient was treated subcutaneously. After 12 weeks of therapy both patients achieved Hb levels within the target range, confirming the effi cacy of epoetin zeta in patients with thalassemia minor.

Long-term safety and tolerability of epoetin zeta, administered intravenously, for maintenance treatment of renal anemia

INTRODUCTION

The aim of this trial was to gather data on the long-term safety of a new erythropoietin preparation (epoetin zeta), focusing on the formation of anti-erythropoietin antibodies, when administered intravenously for maintenance of target hemoglobin concentration in anemic patients with end-stage renal failure receiving chronic hemodialysis. In addition, we aimed to provide information on the efficacy of epoetin zeta under open, noncontrolled conditions.

METHODS

Patients received epoetin zeta intravenously, 1-3 times/week for 56 weeks (overall patient group, n=745) or 108 weeks (Bulgarian subgroup, n=164). The aim of treatment was to maintain hemoglobin values between 10.5 and 12.5 g/dL with constant epoetin dosage. Primary (safety) endpoints were the occurrence of anti-erythropoietin antibodies and the evaluation of adverse events (AEs). Secondary (efficacy) endpoints included the mean weekly dose of epoetin per kg of body weight and mean hemoglobin concentrations.

RESULTS

No patients developed neutralizing anti-erythropoietin antibodies. The most commonly reported AEs were infections and infestations (34.1%); followed by injury, poisoning, and procedural complications (25.8%); and gastrointestinal disorders (21.9%); 37.3% of patients reported serious AEs. The hemoglobin values remained stable, with mean values after 56 weeks of 11.3-11.6 g/dL for the overall group and 11.1-11.6 g/dL for the Bulgarian subgroup. The dosage of epoetin zeta was stable throughout the course of the trial. No cases of lack of (or loss of ) efficacy were observed in the course of the trial.

CONCLUSIONS

The evaluation of the primary endpoints provided data supporting the intravenous administration of epoetin zeta in patients with chronic renal failure. Neutralizing antibodies against erythropoietin were not detected, and there were no reports of patients with increasing erythropoietin resistance. Our results suggest that intravenous administration of epoetin zeta is effective regarding its ability to maintain stabilized hemoglobin levels within the target range of 10.5-12.5 g/dL.

The use of truncated area under the curves in the bioequivalence evaluation of long half-life drugs. Studies with donepezil and memantine

The bioequivalence of long terminal half-life drugs, donepezil (CAS 120014-06-4) 10 mg and memantine (CAS 19982-08-2) 10 mg, was evaluated by comparing the results obtained for the total areas under the concentration time curves (AUC(0-inf)) with those for partial AUCs: AUC(0-216h), AUC(0-72h) and AUC(0-48h). Pharmacokinetic endpoints were determined by standard formulas from the concentration-time courses of the parent compounds donepezil and memantine. The results of the bioequivalence assessment based on the 90% confidence intervals calculated by means of ANOVA for logarithmically transformed values (ANOVA log) led to exactly the same decision irrespective of the type of AUC used. The 90% confidence intervals for all types of AUCs were practically identical within each product. These results prove that truncated AUCs, e.g. AUC(0-72h) or even AUC(0-48h), can be adequately used in assessing the relative bioavailability of long terminal half-life drugs. The findings suggest that even for drugs with half-lives between 24 and 60 h and thus shorter than those of donepezil and memantine an AUC truncated to 48 h post dose can be successfully used for the assessment of bioequivalence as this sample collection time ensures a proper comparison of the absorption process as recommended in the CPMP Note for Guidance on the Investigation of Bioavailability and Bioequivalence.

Evaluation of the pharmacokinetics of two recombinant human erythropoietin preparations: epoetin zeta and epoetin alfa. 1st Communication: A monocentric, open, randomized, single dose, two-period crossover trial in healthy volunteers

The pharmacokinetic properties of a new recombinant erythropoietin preparation (epoetin zeta, CAS 604802-70-2) compared to a reference product (epoetin alfa, CAS 113427-24-0) were analyzed after a single intravenous bolus injection of 10,000 IU in a two-period crossover design in 24 healthy volunteers. Peripheral venous blood samples were obtained pre-dose, and 0:05, 0:20, 0:40, 1:00, 1:20, 1:40, 2:00, 3:00, 4:00, 6:00, 8:00, 12:00, 24:00, 36:00, 48:00, and 72:00 hours post dosing. Samples of 24 volunteers were analyzed by means of a specific immunoassay (ELISA). Three volunteers were excluded from statistical analysis due to a paravasal injection in one of both study periods with resulting low plasma levels of epoetin. Comparison of both preparations showed nearly identical pharmacokinetic properties after intravenous administration. The usual bioequivalence limits were fulfilled for all relevant pharmacokinetic parameters.

Comparison of the therapeutic effects of epoetin zeta and epoetin alpha in the correction of renal anaemia

OBJECTIVE

To assess the therapeutic equivalence of epoetin zeta and epoetin alpha for correction of haemoglobin (Hb) concentration in patients with anaemia and chronic kidney disease (CKD) stage 5 maintained on haemodialysis.

STUDY DESIGN

In total, 609 patients with CKD and anaemia (Hb < 9 g/dL) were randomly assigned to receive either epoetin zeta or epoetin alpha intravenously, one to three times per week for 24 weeks. Dosing was titrated individually to achieve a stable, target Hb concentration of 11-12 g/dL. Primary endpoints were the mean weekly dose of epoetin per kilogram of body weight and mean Hb concentration during the last 4 weeks of treatment. Safety endpoints were the occurrence of anti-erythropoietin antibodies, ratings of tolerability and adverse events (AEs).

RESULTS

Mean (+/- standard deviation [SD]) Hb concentration over the last 4 weeks of treatment was 11.61 +/- 1.27 g/dL for patients receiving epoetin zeta, compared with 11.63 +/- 1.37 g/dL for patients receiving epoetin alpha (95% confidence interval [CI]: -0.25 to 0.20 g/dL). Mean (+/- SD) epoetin zeta weekly dose over the last 4 weeks of treatment was 182.20 +/- 118.11 IU/kg/wk, compared with 166.14 +/- 109.85 IU/kg/wk for epoetin alpha (95% CI: -3.21 to 35.34 IU/kg/wk). The most commonly reported AEs (> 5% of patients) were infections and infestations (12.5% and 12.8% of patients treated with epoetin zeta and epoetin alpha, respectively) and vascular disorders (8.5% and 8.9%, respectively). No patients developed neutralizing anti-erythropoietin antibodies.

CONCLUSIONS

Epoetin zeta, administered intravenously, is therapeutically equivalent to epoetin alpha in the correction of low Hb concentration in patients with CKD undergoing haemodialysis. No unexpected AEs were seen and both epoetin zeta and epoetin alpha were well tolerated.

Comparison of the therapeutic effects of epoetin zeta to epoetin alfa in the maintenance phase of renal anaemia treatment

OBJECTIVE

To evaluate the therapeutic efficacy and safety of epoetin zeta, compared with epoetin alfa, in maintaining target haemoglobin (Hb) concentrations in patients with anaemia and chronic kidney disease (CKD) maintained on haemodialysis.

METHODS

Patients received epoetin zeta or epoetin alfa intravenously, 1-3 times/week for 12 weeks, then the alternative treatment for 12 weeks, in this double-blind, crossover, phase III trial. Eligible patients were 18-75 years old with CKD stage 5 maintained on haemodialysis. Patients had received epoetin for > or = 3 months upon study entry and had achieved a target Hb level of 10.5-12.5 g/dL with a stable epoetin dose.

MAIN OUTCOME MEASURES

Primary efficacy endpoints were intra-individual differences (test-reference) in mean Hb levels and mean weekly dose/kg of body weight. Safety endpoints included occurrence of neutralizing anti-erythro poietin antibodies, tolerability, and adverse events (AEs).

RESULTS

In total, 313 patients were randomized to receive epoetin zeta (n = 155) or epoetin alfa (n = 158); 146 and 145 patients (respectively) switched treatment after 12 weeks. Mean (range) Hb levels were 11.35 (8.96-14.22) g/dL and 11.54 (8.74-13.84) g/dL for patients receiving epoetin zeta and epoetin alfa, respectively (95% confidence interval [CI] [test-reference]: 0.09-0.28 g/dL, within the predefined equivalence range of +/-0.6 g/dL). Mean (range) weekly doses were 92.68 (12.74-398.41) IU/kg/wk and 92.58 (10.53-393.07) IU/kg/wk for patients receiving epoetin zeta and epoetin alfa, respectively (95% CI [test-reference]: -4.67 and 4.29 IU/kg/wk, within the equivalence range of +/-45.00 IU/kg/wk). Patients underwent minor nominal dose adjustments during treatment crossover. AE profile was similar for both products; the most commonly reported AEs were infections and infestations (in 26.5% of patients receiving epoetin zeta and 23.6% receiving epoetin alfa). No patients developed neutralizing anti-erythropoietin antibodies.

CONCLUSIONS

Epoetin zeta is therapeutically equivalent to epoetin alfa in the maintenance of target Hb levels in patients with renal anaemia. No unexpected AEs were seen.

[A randomized, double blind, placebo-controlled study of the efficacy and safety of tolperisone in spasticity following cerebral stroke]

To study the efficacy and safety of tolperisone--a centrally acting muscle relaxant with membrane stabilizing activity--in the treatment of stroke-related spasticity. This was a randomized, double-blind, placebo-controlled, multicenter study with parallel groups. Treatment lasted 12 weeks and was started with a titration period of variable length (dose range 300-900 mg tolperisone daily). The degree of spasticity determined on the Ashworth Scale in the most severely affected joint area was denned as primary target parameter. Hundred and twenty patients (43 females, 77 males) in a mean age of 63,3 +/- 10,6 years were recruited and received treatment. In the majority of patients both limbs of each side were affected by the spasticity which on average had been present for 3,3 +/- 4,4 years. A 62% of the patients were treated with a daily dose >600 mg tolperisone. Tolperisone reduced the mean Ashworth Score by a mean of 1,03 +/- 0,71 compared with a mean reduction of 0,47 +/- 0,54 in the placebo group (p<0,0001). A 78,3% of the patients on tolperisone versus 45% of the placebo patients experienced a reduction by at least 1 point on the Ashworth Scale (p<0,0001). Functional and overall assessments of efficacy confirmed superior efficacy of tolperisone. Adverse events occurred less often on active treatment (n=19) than on placebo (n=26) and were mostly of mild-to-moderate intensity. No withdrawals caused by adverse events were reported in the tolperisone group. The findings of the present study demonstrate the efficacy and excellent tolerance of tolperisone in the treatment of spastic hypertonia following cerebral stroke. Study data further suggest that an individual dose titration which may exceed the recommended maximum dose of 450 mg daily results in optimized therapeutic benefit.

Bioequivalence studies with metformin: comparability of reference tablets from different origins

BACKGROUND

The choice of an appropriate reference product is still a problem within the European Union. When no direct comparisons between originator products in different countries are available, registration authorities are sometimes only prepared to grant registration for a generic product on the basis of a comparison with the originator product in the respective country. The aim of the investigation was therefore to evaluate the bioequivalence of reference products from different origins in two different bioequivalence trials with the same test drug.

METHODS

Two separate bioequivalence trials were performed involving the oral administration of one test and two reference products containing 500 mg metformin. Both studies had a randomized, open, single-dose, three-period crossover design and were carried out in 24 healthy volunteers. The reference products in the first trial were Glucophage mite (Germany) and Diabex (Australia). In the second trial the reference drugs were Glucophage mite (France) and Glucophage mite (Switzerland). The results of each trial were analyzed regarding the bioequivalence of the respective reference drugs.

FINDINGS

The reference drugs in each of both trials were bioequivalent: the 90% confidence intervals for both AUC(0-tlast) and C(max) were entirely within the acceptance range for bio-equivalence trials (0.80 - 1.25 for both parameters).

INTERPRETATION

In the case of metformin, the reference products available in the countries examined were very similar. This retrospective analysis involving two studies, therefore, confirmed bioequivalence between these reference products.

A randomized, double-blind, placebo-controlled study of the efficacy and safety of tolperisone in spasticity following cerebral stroke

To study the efficacy and safety of tolperisone - a centrally acting muscle relaxant with membrane stabilizing activity - in the treatment of stroke-related spasticity. This was a randomized, double-blind, placebo-controlled, multicenter study with parallel groups. Treatment lasted 12 weeks and was started with a titration period of variable length (dose range 300-900 mg tolperisone daily). The degree of spasticity determined on the Ashworth Scale in the most severely affected joint area was defined as primary target parameter. Hundred and twenty patients (43 females, 77 males) in a mean age of 63.3 +/- 10.6 years were recruited and received treatment. In the majority of patients both limbs of each side (right: n = 59; left: n = 56) were affected by the spasticity which on average had been present for 3.3 +/- 4.4 years. A 62% of the patients were treated with a daily dose >/=600 mg tolperisone. Tolperisone reduced the mean Ashworth Score by a mean of 1.03 +/- 0.71 compared with a mean reduction of 0.47 +/- 0.54 in the placebo group (P < 0.0001). A 78.3% of the patients on tolperisone versus 45% of the placebo patients experienced a reduction by at least 1 point on the Ashworth Scale (P < 0.0001). Functional and overall assessments of efficacy confirmed superior efficacy of tolperisone. Adverse events occurred less often on active treatment (n = 19) than on placebo (n = 26) and were mostly of mild-to-moderate intensity. No withdrawals caused by adverse events were reported in the tolperisone group. The findings of the present study demonstrate the efficacy and excellent tolerance of tolperisone in the treatment of spastic hypertonia following cerebral stroke. Study data further suggest that an individual dose titration which may exceed the recommended maximum dose of 450 mg daily results in optimized therapeutic benefit.

Bioequivalence study of levothyroxine tablets compared to reference tablets and an oral solution

The study was designed to evaluate the bioequivalence of three levothyroxine sodium (CAS 51-48-9) formulations, i.e. a test and a reference tablet and an oral solution. A bioequivalence study was carried out in 25 healthy volunteers, who were administered a single dose of 600 microg levothyroxine in the form of the test formulation (levothyroxine sodium tablets 200 microg; Eferox), the originator product, and an oral solution. The trial was performed in one study center according to an open, randomized, three-way cross-over design with wash-out periods of 35 days between administration. Blood samples were taken up to 48 h post dose, the plasma was separated and the concentrations of levothyroxine and triiodothyronine were determined by radioimmunoassay with I125 labeling method. The levothyroxine mean Cmax were 112.0+/-17.3 ng/ml, 113.4+/-18.5 ng/ ml and 111.3+/-15.1 ng/ml, while the mean AUC0-24 were 2263.7+/-332.8 ng x h/ ml, 2307.3+/-351.3 ng x h/ml and 2286.1+/-331.0 ng x h/ml for the test and reference tablets as well as for the oral solution, respectively. No significant differences were found of principal pharmacokinetic parameters between the studied formulations. The 90%-confidence interval for the primary target parameters, intra-individual ratios of AUC0-24 and Cmax of levothyroxine were within the acceptance ranges for bioequivalence trials, i.e. AUC0-24 0.954-1.016 and 0.966-1.011 as well as Cmax 0.948-1.027 and 0.968-1.032 for test tablets versus reference tablets and the oral solution, respectively. Similar results were observed for triiodothyronine. In the light of the present study it can be concluded that the levothyroxine test tablet is bioequivalent to the reference formulation in respect of extent and rate of absorption. The results of the present trial confirm the findings of a previous study, performed under steady-state conditions with Eferox tablets 100 microg in patients without thyroid function.

Studies on the bioequivalence of different strengths of tablets containing clarithromycin

The aim of the present studies, performed in two different groups of volunteers, was to compare the bioavailability of clarithromycin (CAS 81103-11-9) tablets (Klaromin, test tablets) containing 250 mg (study 1) or 500 mg (study 2) of the drug with reference tablets of the same strength. Each study was conducted according to an open, randomized, single-dose, two-period crossover design in healthy volunteers with a wash-out period from 7 to 14 days. Blood samples were taken up to 24 h in both studies, and concentrations of clarithromycin and its principal active 14-hydroxy metabolite were determined by HPLC method. In the first study, the 90% confidence interval for intra-individual ratios of AUC0-t and Cmax of clarithromycin were between 0.93 and 1.05 (AUC0-t) as well as between 0.90 and 1.18 (Cmax). In the second study, i.e. after administration of clarithromycin 500 mg tablets, the 90% confidence interval for intra-individual ratios of AUC0-t and Cmax of clarithromycin were between 0.90 and 1.08 (AUC0-t) as well as between 0.85 and 1.22 (Cmax). All these values were within the acceptance ranges for bioequivalence studies. In both studies, the 90% confidence interval for intra-individual ratios of AUC0-t and Cmax of 14-hydroxy-clarithromycin were also within the acceptance ranges, although the confidence intervals for these parameters were not planned to be compared with the acceptance ranges. In the light of the results of the studies reported here it can be concluded that the clarithromycin 250 mg and 500 mg test tablets are bioequivalent to the respective reference formulations.

Bioequivalence study of atorvastatin tablets

The study was designed to evaluate the relative bioavailability of two formulations of atorvastatin (CAS 134523-03-8). A bioequivalence study was carried out in 24 healthy male volunteers who received four 10 mg tablets of the test formulation (Kolestor) and the same dose of the originator product. The trial was performed according to an open, crossover design with a wash-out period of 7 days in one study center. Blood samples were taken up to 48 h post dose, the plasma was separated and the concentrations of atorvastatin were determined by HPLC-MS-MS method. The mean Cmax were 16.37 ng/mL and 17.05 ng/mL, while the mean AUC0-t were 103.61 ng x h/mL and 102.55 ng x h/mL for the test and reference formulations, respectively. The mean AUC0-inf were 118.10 ng x h/mL and 117.13 ng x h/mL for the test and reference formulations, respectively. The median tmax was 0.67 h for both the test tablet and the reference product. The mean t(1/2 el) was 11.85 h for the test formulation and 13.28 h for the reference formulation. No significant differences of pharmacokinetic parameters between the two studied formulations were found. The 90% confidence intervals for the primary target parameters, intra-individual ratios of AUC0-t and Cmax of atorvastatin, were between 0.85 and 1.05 (AUC0-t) and between 0.84 and 1.23 (Cmax), respectively, and thus within the acceptance ranges. Concerning the secondary parameter tmax the 90% confidence interval for the intra-individual differences was between -0.17 and 0.17 h. In the light of the present study it can be concluded that the two evaluated atorvastatin formulations, i.e. test formulation of atorvastatin and reference preparation are bioequivalent in terms of the rate and extent of absorption.

Bioequivalence study of rofecoxib tablets

The study was designed to evaluate the bioavailability of two rofecoxib (CAS 162011-90-7) tablet formulations. Twenty-four healthy male volunteers were administered a 25 mg tablet of the test formulation (Ecrox) containing rofecoxib or the originator product (reference). The trial was performed according to an open, cross-over design with a wash-out period of 7 days. Blood samples were taken up to 72 h post dose, the plasma was separated and the concentrations of rofecoxib were determined by an HPLC method. The mean Cmax were 192.07 ng/mL and 187.35 ng/mL, while the mean AUC0-t were 3613.84 ng x h/mL and 3501.56 ng x h/mL for the test and reference formulations, respectively. The median tmax was 3.75 h for the test tablet and 4.00 h for the reference formulation. The mean t(1/2 el) was 10.66 h and 10.61 h for the test and reference formulation, respectively. Mean MRT values for the test and reference tablets were 15.34 h and 15.33 h, respectively. Mean MRT values for the test and reference tablets were 15.34 h and 15.33 h, respectively. No significant differences of pharmacokinetic parameters between the two studied formulations were found. The 90% confidence interval for the primary target parameters, i.e. intra-individual ratios of AUC0-t and Cmax of rofecoxib were between 0.99 and 1.10 (AUC0-t) as well as between 0.96 and 1.10 (Cmax) and thus within the acceptance ranges. Concerning the secondary parameter tmax the 90% confidence interval for the intra-individual differences was between -0.25 and 0.25 h. In the light of the present study it can be concluded that the two evaluated rofecoxib formulations, i.e. test tablets of rofecoxib and a reference preparation are bioequivalent in terms of the rate and extent of absorption.

Effect of the formulation on the bioequivalence of sultamicillin: tablets and suspension

Sultamicillin (CAS 76497-13-7) is a pro-drug of a combination of ampicillin and sulbactam linked as a double ester. The aim of the present studies, performed in two different groups of volunteers, was to compare the bioavailability of 750 mg sultamicillin tablets (Duobaktam 750 mg tablets, study 1) and sultamicillin 250 mg/5mL suspensions (Duobaktam 250 mg/5mL, study 2). Each study was conducted according to an open, randomized, single-dose, two-period cross-over design in 24 healthy volunteers with a wash-out period from 7 to 14 days. Blood samples were taken up to 12 h post dosing, and concentrations of ampicillin and sulbactam were determined by a HPLC-UV method. In the first study, the 90% confidence interval for intra-individual ratios of AUC0-t and Cmax of ampicillin and sulbactam were between 1.01-1.18 and 0.95-1.09 (AUC0-t) as well as between 0.87-1.04 and 0.80-0.96 (Cmax), respectively, and thus within the acceptance ranges. The 90% confidence interval for intra-individual ratios of AUC0-t and Cmax of sultamicillin suspensions (2nd study) were between 0.94-1.16 (ampicillin) and 0.92-1.14 (sulbactam) for AUC0-t and between 0.96-1.23 (ampicillin) and 0.97-1.24 (sulbactam) for Cmax. These values were also within the acceptance range for bioequivalence studies. Concerning the secondary parameter tmax the 90%-confidence interval for the intra-individual differences for both ampicillin and sulbactam were between 0.00-0.50 in the first and between -0.17-0.00 in the second study, respectively. In the light of the present studies it can be concluded that the sultamicillin test formulations, i.e. tablet and suspension are bioequivalent to the respective reference formulations.

Assessment of the bioequivalence of different formulations containing azithromycin (tablets and suspension)

Azithromycin (CAS 11772-70-0) is an orally administered macrolide antimicrobial drug, structurally related to erythromycin, with a similar spectrum of antimicrobial activity. The aim of the present studies, performed in two different groups of volunteers, was to compare the bioavailability of azithromycin (Azro) 500 mg tablets (study 1) and azithromycin (Azro) 200 mg/5 mL suspensions (study 2) with originator products. Each study was conducted according to an open, randomized, single-dose, two-period cross-over design in 24 healthy volunteers with a wash-out period from 14 to 21 days. Blood samples were taken up to 96 h post dosing, and concentrations of azithromycin were determined by HPLC method. In the first study, the 90% confidence interval for intra-individual ratios (test vs. reference) of AUC0-t and Cmax of azithromycin were between 0.82 and 1.04 for AUC0-t and 0.81 and 1.11 for Cmax, and thus within the acceptance ranges for bioequivalence trials. The 90% confidence interval for intra-individual ratios of AUC0-t and Cmax of azithromycin administered as suspension were between 0.89 and 1.22 and 0.91 and 1.23, respectively. These values were also within the acceptance range. Concerning the secondary parameter tmax the 90% confidence interval for the intra-individual differences for azithromycin were between -0.49 - 0.50 in the first and between -0.50 - 0.25 in the second study, respectively. In the light of the results of the studies reported here it can be concluded that azithromycin test formulations, i.e. tablet and suspension are bioequivalent to the respective reference formulations.

Studies on the bioequivalence of second generation cephalosporins: cefaclor capsules and suspension

The aim of the present studies, performed in two different groups of volunteers, was to prove the bioequivalence of 500 mg cefaclor (CAS 70356-03-5) test and reference capsules (Losefar 500 mg Capsules as test and an originator product as reference; study 1) and cefaclor 250 mg/5 mL test and reference suspensions (Losefar 250 mg/5 mL Granules oral suspension as test and an originator product as reference; study 2). Each study was conducted according to an open, randomized, single-dose, two-period cross-over design in healthy volunteers with a wash-out period from 7 to 14 days. Blood samples were taken up to 8 h post dosing, and concentrations of cefaclor were determined by HPLC method. In the first study, the 90% confidence intervals for intra-individual ratios of AUC0-t and Cmax of cefaclor were 0.99-1.08 for AUC0-t and 0.82-1.06 for Cmax, and thus within the acceptance ranges for bioequivalence trials. The 90% confidence interval for intra-individual ratios of AUC0-t and Cmax of cefaclor administered as suspensions were 1.10-1.19 and 1.02-1.21, respectively. These values were also within the acceptance range. Concerning the secondary parameter tmax the 90% confidence interval for the intra-individual differences for cefaclor were between -0.13 - 0.13 in the first and between 0.00 - 0.13 in the second study, respectively. In the light of the results of the studies reported here it can be concluded that cefaclor test formulations, i.e. capsules and suspension are bioequivalent to the respective reference formulations.

Clarithromycin suspension: bioequivalence studies on two different strengths

Two studies were performed in different groups of volunteers, with the aim to prove the bioequivalence of test (Klaromin) and reference clarithromycin (CAS 81103-11-9) suspensions containing in 5 mL either 125 mg (study 1) or 250 mg (study 2) of the drug, administered as an oral dose of 10 mL. Each study was conducted according to an open, randomized, single-dose, two-period cross-over design in healthy volunteers with a wash-out period from 7 to 14 days. Blood samples were taken up to 24 h in both studies, and concentrations of clarithromycin and its principal active 14-hydroxy metabolite were determined by HPLC. In the first study, the 90% confidence interval for intra-individual ratios of AUC0-t and Cmax of clarithromycin were between 0.84 and 1.03 (AUC0-t) and between 0.89 and 1.03 (Cmax). In the second study, i.e. after administration of clarithromycin suspension 250mg/5mL, the 90% confidence interval for intra-individual ratios of AUC0-inf and Cmax of clarithromycin were between 1.01 and 1.17 (AUC0-inf) and between 1.01 and 1.16 (Cmax). All these values were within the acceptance ranges for bioequivalence studies. In both studies, the 90% confidence interval for intra-individual ratios of AUC0-inf and Cmax of 14-hydroxy-clarithromycin were also within the acceptance ranges. In the light of the results of the studies reported here it can be concluded that the clarithromycin test formulations are bioequivalent to the respective reference formulations, i.e. suspensions containing 125 mg/5 mL and 250 mg/5 mL of the drug.

Effect of the combination of lisinopril and hydrochlorothiazide on the bioequivalence of tablet formulations

The aim of the present studies, performed in two different groups of volunteers, was to compare the bioavailability of 20 mg lisinopril tablets (Sinopryl as test and an orignator product as reference formulation; study 1) and lisinopril/hydrochlorothiazide (20 mg/12.5 mg) (CAS 83915-83-7/CAS 58-93-5) combined formulations (Sinoretik as test and an originator product as reference formulation; study 2). Each study was conducted according to an open, randomized, single-dose, two-period cross-over design in healthy volunteers with a wash-out period from 7 to 14 days. Blood samples were taken up to 72 h in both studies, the plasma was separated. Concentrations of lisinopril and hydrochlorothiazide were determined by HPLC-MS-MS method. In the first study, the 90% confidence interval for intra-individual ratios of AUC0-t and Cmax of lisinopril were between 0.85 and 1.12 (AUC0-t) and between 0.87 and 1.17 (Cmax), and thus within the acceptance ranges. In the second study, i.e. after administration of combined lisinopril/hydrochlorothiazide formulations, the 90% confidence interval for intra-individual ratios of AUC0-inf and Cmax of lisinopril were between 0.83 and 1.22 (AUC0-inf) and between 0.80 and 1.25 (Cmax). The 90% confidence interval for intra-individual ratios of AUC0-inf and Cmax of hydrochlorothiazide were between 0.92 and 1.04 (AUC0-inf) and between 0.88 and 1.08 (Cmax). All the above values were within the acceptance ranges for bioequivalence studies. In the light of the present studies it can be concluded that Hsinopril as well as lisinopril/hydrochlorothiazide test formulations are bioequivalent to the respective reference formulations.

Combination of losartan and hydrochlorothiazide: in vivo bioequivalence

Two trials were performed in different groups of volunteers with the aim to compare the bioavailability of 50 mg losartan tablets (Sarvas as test and an originator product as reference formulation; study 1) and losartan/hydrochlorothiazide (50 mg/12.5 mg) (CAS 124750-99-8/CAS 58-93-5) combined formulations (Sarvastan as test and an originator product as reference formulation; study 2), respectively. Each study was conducted according to an open, randomized, single-dose, two-period cross-over design in 24 healthy volunteers with a wash-out period from 7 to 14 days. Blood samples were taken up to 36 h in the first study and up to 48 h in the second study. Concentrations of losartan and its principal active metabolite, i.e. E3174, as well as hydrochlorothiazide were determined by HPLC or LC-MS-MS, respectively. In the first study, the 90% confidence interval for intra-individual ratios of AUC0-t and Cmax of losartan were between 0.91 and 1.03 (AUC0-t) as well as between 0.87 and 1.19 (Cmax), and thus within the acceptance ranges. The 90% confidence interval for intra-individual ratios of AUC0-t, and Cmax of E3174 were between 0.90 and 1.13 for AUC0-t, and between 0.97 and 1.14 for Cmax. In the second study, i.e. after administration of combined losartan/hydrochlorothiazide formulations, the 90% confidence interval for intra-individual ratios of AUC0-t and Cmax of losartan were between 0.90 and 1.04 (AUC0-t) as well as between 0.86 and 1.20 (Cmax). Similarly to the parent compound, no significant differences of bioavailability parameters of E3174 between the two studied formulations were found. The 90% confidence interval for intra-individual ratios of AUC0-t and Cmax of hydrochlorothiazide were between 0.89 and 0.98 (AUC0-t) as well as between 0.82 and 1.00 (Cmax). In the light of the present studies it can be concluded that the losartan as well as losartan/hydrochlorothiazide test formulations are bioequivalent to the respective reference formulations.

Analysis of pooled plasma samples as a predictor for proving bioequivalence of drugs with a long elimination half-life. The example of phenprocoumon

The results of pooled plasma analysis in a bioequivalence trial provide information comparable with that of the mean concentration vs. time curves for each formulation. Although it seems feasible that pool plasma analysis will have similar or even greater advantages in cases of bioequivalence trials with a parallel-group design, no such data has been published in the literature probably due to the limited number of such trials. The present study was designed with the aim to investigate the prediction value of pool plasma analysis in a bioequivalence trial with phenprocoumon (CAS 435-972). The study was performed as a monocentric, randomized, open clinical trial in two parallel groups of healthy male volunteers (31 per group), all of which received a single oral dose of 3 mg phenprocoumon. Serial blood samples were drawn for the pharmacokinetic analysis pre-dose, and 0.33, 0.67, 1, 1.5, 2, 2.5, 3, 3.5, 4, 6, 12, 24, 48, 96, 144, 192, and 240 h after drug administration. Pool plasma was prepared for each sampling point and each formulation. Drug concentrations were measured by means of an HPLC method. A comparison between the pool plasma results and the results of individual analysis revealed a very good correspondence regarding the parameters AUC, Cmax and t(max). The present trial demonstrates that the method of time-wise pooling provides reliable information not only in cross-over trials but also in trials with parallel groups of volunteers.

Clinical relevance of bioequivalence acceptance criteria. The example of terbinafine

OBJECTIVE

The present study was conducted with the aim of investigating which acceptance criteria for bioequivalence are relevant for orally applied antimycotics using terbinafine (CAS 78628-80-5) as an example.

METHODS

A bioequivalence trial was performed in 18 healthy male volunteers with the aim of comparing a new generic product (tablets containing terbinafine hydrochloride, equivalent to 250 mg base) with the originator product. The trial was performed according to an open, cross-over design in one study centre. In each of the two study periods (separated by a wash-out of 14 days) a single dose of one 250 mg tablet (test or reference) was administered. Blood samples were taken up to 72 h post dose, the plasma was separated and the concentrations of terbinafine were determined by a liquid chromatography-mass spectrometry (LC-MS-MS) method with a quantification limit of 14 ng/ml. AUC0-infinity, AUC0-tlast, Cmax and tmax were calculated for both formulations and compared according to the currently valid CPMP Note for Guidance for the evaluation of Bioavailability and Bioequivalence.

RESULTS

The parametric 90% confidence intervals for the primary target parameters were between 0.89 and 1.09 AUC0-tlast and between 0.71 and 0.95 for Cmax. The acceptance ranges prospectively defined in the protocol for this trial were fulfilled. In the light of the currently valid CPMP Note for Guidance, the question still arose whether the overall positive bioequivalence statement was clinically feasible. Taking into account the mechanism of action and the available efficacy and safety data on terbinafine, this question was answered positively.

CONCLUSION

In the case of oral antimycotic agents and especially terbinafine, the bioequivalence acceptance range for Cmax can be expanded to 0.7-1.43, if the acceptance criteria for AUC are fulfilled.

Evaluation of the efficacy of a combined formulation (Grippostad-C) in the therapy of symptoms of common cold: a randomized, double-blind, multicenter trial

BACKGROUND

The aim of the present trial was to evaluate the efficacy of a combined product in the treatment of common cold and to examine the contribution of the separate components. In the published literature there is conflicting data on the efficacy of agents used in the treatment of common cold, especially when given in drug combinations.

METHODS

A prospective, randomized, double-blind, multicenter, 4-arm, controlled trial was carried out in 1,167 patients with common cold treated with one of the following medications: Grippostad-C, a combination of acetaminophen, caffeine, chlorpheniramine and ascorbic acid (verum), ascorbic acid (control), chlorpheniramine and ascorbic acid (reference 1), as well as acetaminophen, caffeine, and ascorbic acid (reference 2). A score of common cold symptoms (headache, throat pain, extremities and joint pain, cough, blocked nose, and disturbances of sleep quality) was the primary outcome. The test drug was first compared with the control using a hierarchic test strategy, then with reference 1, followed by reference 2 with the aim of proving superiority.

FINDINGS

A clinically relevant and statistically significant difference was demonstrated at each level of the hierarchy. Grippostad-C was significantly superior to all other treatment groups, the combination of acetaminophen, caffeine, and ascorbic acid was significantly superior to the control, and the combination of chlorpheniramine and ascorbic acid was not statistically different from the control.

INTERPRETATION

The efficacy of Grippostad-C for the treatment of common cold was proven. The findings demonstrate that the combination is superior to each of its separate components and each of the components has its own distinctive contribution to the efficacy of the combination product.

Comparison of the efficacy and endometrial safety of two estradiol valerate/dienogest combinations and Kliogest for continuous combined hormone replacement therapy in postmenopausal women

OBJECTIVE

To compare the efficacy and endometrial safety of two estradiol valerate/dienogest combinations with Kliogest in the treatment of postmenopausal symptoms.

DESIGN

This was a double-blind, randomized, multicenter study.

METHODS

Patients were randomized to estradiol valerate 2.0 mg/dienogest 2.0 mg (Climodien), estradiol valerate 2.0 mg/dienogest 3.0 mg (E2Val 2/DNG 3); or estradiol 2.0 mg/estriol 1.0 mg/norethisterone acetate 1.0 mg (Kliogest) once daily for 1 year. The primary efficacy variable was the Kupperman index. Endometrial safety was determined primarily by biopsy.

RESULTS AND CONCLUSIONS

Climodien and E2Val 2/DNG 3 were therapeutically equivalent to Kliogest (mean changes in Kupperman index -20.1, -19.0 and -18.3, respectively). No statistically significant differences existed between treatment groups in the severity of postmenopausal symptoms. The incidences of endometrial atrophy were similar in all groups. Climodien appeared to be superior to Kliogest in terms of vaginal bleeding pattern, whereas E2Val 2/DNG 3 was associated with a slightly higher incidence and greater intensity of vaginal bleeding. The incidences of adverse events were similar in all groups. A greater proportion of women in the Kliogest and E2Val 2/DNG 3 groups experienced vaginal bleeding, whereas breast problems were more common with Climodien. Climodien and E2Val 2/DNG 3 induced desirable changes in insulin-like growth factor I (decrease) and sex hormone binding globulin (increase) that were not seen with Kliogest.

Balm mint extract (Lo-701) for topical treatment of recurring herpes labialis

A double-blind, placebo-controlled, randomized trial was carried out with the aim of proving efficacy of standardized balm mint cream [active ingredient: 1% Lo-701--dried extract from Melissa officinalis L. leaves (70:1)] for the therapy of herpes simplex labialis. Sixty six patients with a history of recurrent herpes labialis (at least four episodes per year) in one center were treated topically; 34 of them with verum and 32 with placebo. The cream had to be smeared on the affected area four times daily over five days. A combined symptom score of the values for complaints, size of affected area and blisters at day 2 of therapy was formed as the primary target parameter. There was a significant difference in the values of the primary target parameter between both treatment groups: verum 4.03 +/- 0.33 (3.0); placebo 4.94 +/- 0.40 (5.0); values given are mean +/- SEM (median) of the symptoms score on day 2 of therapy. The tested formulation is effective for the treatment of herpes simplex labialis. The significant difference in the combined symptom score on the second day of treatment is of particular importance having in mind that the complaints in patients suffering from herpes labialis are usually most intensive at that time. In addition to the shortening of the healing period, the prevention of a spreading of the infection and the rapid effect on typical symptoms of herpes like itching, tingling, burning, stabbing, swelling, tautness and erythema, the balm mint cream has a further advantage. The different mechanism of action of the balm mint extract rules out the development of resistance of the herpes virus. Some indication exists that the intervals between the periods with herpes might be prolonged with balm mint cream treatment.

Pharmacokinetics of orally administered estradiol valerate. Results of a single-dose cross-over bioequivalence study in postmenopausal women

A randomized, single-dose cross-over study in 32 postmenopausal women was performed to demonstrate bioequivalence of two estradiol valerate containing formulations (first sequence of Klimonorm as test preparation). The serum levels of estradiol, free and conjugated estrone were measured until 48 h after an oral dosage of 4 mg estradiol valerate (CAS 979-32-8). The mean AUC(0-48) of estradiol was calculated as 1006.6 +/- 479.4 h x pg x ml-1 (Test) and 1015.2 +/- 555.2 h x pg x ml-1 (Reference). The corresponding (AUC(0-48) of the active metabolite, free estrone, exceeded that of estradiol at 3578.3 h x pg x ml-1 (Test) and 3485.1 h x pg x ml-1 (Reference). Much higher was the AUC(0-48) for conjugated estrone at 132.4 h x ng x ml-1 (Test) and 133.6 h x ng x ml-1 (Reference). Mean estradiol Cmax values of 39.8 +/- 17.7 pg/ml (Test) and 42.9 +/- 21.0 pg/ml (Reference) were attained 8.2 +/- 4.5 h (Test) and 10.0 +/- 5.9 h (Reference) after the administration of 4 mg estradiol valerate. Maximal free estrone concentrations of 163 pg/ml (Test) and 174.3 pg/ml (Reference) were reached after 7.2 h (Test) and 7.5 h (Reference). Maximal conjugated estrone concentrations of 15.5 ng/ml (Test) and 16.2 ng/ml (Reference) were reached after 2.4 h (Test) and 2.0 h (Reference). The terminal elimination half-life of estradiol was calculated at 16.9 +/- 6.0 h (Test) and 15.0 +/- 4.8 h (Reference), that of free estrone at 16.3 h (Test) and 13.5 h (Reference), that of conjugated estrone at 11.8 h (Test) and 10.6 h (Reference). After logarithmic transformation, the 90% confidence intervals of the AUC(0-48) and Cmax ratios for estradiol and also for the metabolites (free and conjugated estrone) were within the acceptance ranges for bioequivalence. Therefore the test preparation and the reference preparation are bioequivalent.

Influence of the cytochrome P4502D6*4 allele on the pharmacokinetics of controlled-release metoprolol

AIM

The aim of the present paper was to compare the pharmacokinetics of metoprolol in homozygous Caucasian volunteers for the wild-type CYP2D6 allele (CYP2D6*1/CYP2D6*1) and heterozygous (CYP2D6*1/CYP2D6*4) Caucasians.

METHODS

Thirty-six unrelated healthy male Caucasians were screened for two of the most frequently occurring mutant alleles (CYP2D6*3 and CYP2D6*4) using polymerase chain reaction (PCR). Twenty-four volunteers with a genotype suggesting a rapid hydroxylator phenotype were enrolled in a bioequivalence trial and each received in a randomized, cross-over fashion one of the three formulations compared. Each formulation contained 200 mg metoprolol tartrate/(tablet). In each of the three periods of the trial, one of the formulations was administered under fasting conditions in the morning on 4 consecutive days. Blood for quantification of metoprolol was drawn immediately before the last dose and in selected time intervals thereafter. A sensitive and specific high-performance liquid chromatography (HPLC) method with fluorescence detection was applied for the quantification of metoprolol. Pharmacokinetic parameters were determined for each subject and statistically compared in two groups of 16 homozygous (CYP2D6*1/CYP2D6*1) and six heterozygous (CYP2D6*1/CYP2D6*4) volunteers.

RESULTS

Significant differences between homozygous and heterozygous individuals were observed for all pharmacokinetic parameters. The AUC in the course of one those interval of 24 h (AUCtau), minium steady-state concentration (C(min)ss) and average steady-state concentration (C(av)ss) values for heterozygous individuals were more than twice those of individuals. Significantly higher values for C(max)ss, t1/2, half-value duration (HVD) and mean residence time (MRT) were also observed in heterozygous volunteers. The higher concentrations of metoprolol in heterozygous individuals also had pharmacodynamic consequences, namely, greater heart rate and blood pressure reduction.

Absolute bioavailability of oral immediate and slow release fluphenazine in healthy volunteers

OBJECTIVE

The present study was conducted with the aim of investigating the absolute bioavailability of fluphenazine in healthy volunteers after administration of immediate and slow release oral formulations.

METHODS

The oral dose was 12 mg fluphenazine hydrochloride. The intravenous bolus dose was 2.5 mg. Fourteen healthy volunteers of both sexes were enrolled in this randomised, crossover trial. Twelve volunteers completed the trial according to protocol.

RESULTS

The concentration maxima after administration of the slow release formulation were approximately half those measured after the immediate release formulation and were recorded later by a factor of 2 (immediate release: Cmax = 2.3 ng.ml-1, tmax = 2.8 h; slow release: Cmax = 1.2 ng.ml-1, tmax = 4.6 h). The concentrations measured 10 min after intravenous bolus administration of 2.5 mg fluphenazine hydrochloride were approximately 100 times higher (261 ng.ml-1). The geometric means for the absolute bioavailability of fluphenazine were 2.7% for the immediate release formulation and 3.4% for the slow release formulation. The absolute bioavailability of fluphenazine is thus much lower than previously generally accepted.

Influence of food on the bioavailability and some pharmacokinetic parameters of diprafenone--a novel antiarrhythmic agent

OBJECTIVE

The present study was done to investigate the effect of food on the bioavailability of diprafenone.

METHODS

The most important pharmacokinetic parameters (Cmax, t1/2, AUC) and the relative oral availability of a solid oral preparation of racemic diprafenone were investigated when administered to fasting subjects and 10 min after a standard meal, in an open, randomised, crossover trial. Single oral doses of 100 mg were given on two different occasions, at least 1 week apart. The serum concentrations of diprafenone and its hydroxy-metabolite were determined up to 24 hours after administration by a sensitive, specific HPLC method. Fifteen healthy, male volunteers were enrolled in the trial. Their mean height, weight and age were 183 cm, 80 kg and 22 years, respectively. Fourteen volunteers were found to be rapid hydroxylators and one was a slow hydroxylator of debrisoquine. Only data from the rapid hydroxylators were used in the statistical analysis.

RESULTS

Food increased the oral bioavailability of diprafenone by approximately 50%. This effect was similar in rapid and in slow hydroxylators. The only slow hydroxylator in this trial had an AUCzero-last ratio (with food/fasting) of 1.54. These findings suggest that diprafenone should be administered in a constant temporal relationship to food.

Effect of diprafenone on the pharmacokinetics of digoxin

This study was conducted to investigate the effect of diprafenone on the steady-state pharmacokinetics of digoxin. Twelve healthy men, all rapid hydroxylators of debrisoquine, received digoxin (0.5 mg per day over 7 days with a loading dose of 2 x 1 mg) or digoxin and diprafenone (3 x 100 mg per day) in three different phases, without a wash-out period (phase 1, digoxin alone; phase 2, digoxin + diprafenone; phase 3, digoxin alone). Blood and urine samples were collected for pharmacokinetic analyses. Diprafenone caused a statistically significant increase in digoxin trough concentrations [1.4 (SD 0.2) vs 1.6 (0.3) ng.ml-1], AUC(zero)-24 values [41 (7) vs 48 (9) ng.h.ml-1 and Css-max[3.9 (0.6) vs 5.5 (0.9) ng.ml-1]. In all volunteers the parameters tended to return to the original values after administration of diprafenone was discontinued [1.4 (0.3) ng.ml-1, 39 (11) ng.h.ml-1, and 3.9 (1.1) ng.ml-1 for trough concentration, AUC(zero)-24 and Cmax respectively]. The mean relative magnitude of the increase in AUC(zero)-24 and trough concentration values corresponded to the mean relative decrease in the renal clearance of digoxin (in both cases approximately 20%). This suggests that the increase in AUC and Css was caused by reduced renal clearance of digoxin.

Quantitation of R- and S-propafenone and of the main metabolite in plasma

Several methods for the determination of racemic propafenone or its enantiomers as well of the main metabolite R,S-5-hydroxypropafenone are known from the literature. The method described here enables the simple simultaneous quantification of R- and S-propafenone and of R,S-5-hydroxypropafenone in human plasma. The method is based on an HPLC separation using a Chiralpak AD column. High recovery rates (80-95%) were achieved by means of a liquid-liquid-extraction at pH 11 with dichloromethane as solvent. The separation on the chiral carrier were carried out with n-hexane/2-propanol; the addition of diethylamine is useful. The obtained capacity factors are k' = 2.36 for R-propafenone and k' = 3.82 for S-propafenone. R,S-propanolol and R,S-metoprolol were used as internal standards. The method described can be used for pharmacokinetic trials in man with the following limits of quantitation: 10 ng/ml for R- and S-propafenone and 20 ng/ml for R,S-5-hydroxypropafenone.

[The bioequivalence of two oral propafenone preparations]

The bioequivalence of two oral racemic propafenone (CAS 54063-53-5) preparations was tested in an open, randomised, crossover trial with administration of single doses of 300 mg on two different occasions with a washout period of 7 days. 24 healthy, male volunteers, all proved to be rapid hydroxylators of debrisoquine, were enrolled in the trial. The concentrations of R(+)-, S(-)-propafenone and 5-hydroxypropafenone (5-OH-propafenone) were measured up to 12 h after administration by means of a sensitive and specific HPLC method that allowed the simultaneous quantification of all three substances in plasma. The results of 23 volunteers were evaluated pharmacokinetically. Main target parameters were AUC0-infinity and Cmax of both enantiomers of propafenone. Secondary target parameters were AUC0-infinity and Cmax of 5-OH-propafenone as well as tmax for R(+)- and S(-)-propafenone. The 90% confidence intervals for AUC0-infinity for R(+)-, S(-)-, and 5-OH-propafenone were 0.85-1.07, 0.83-1.10 and 0.84-1.05, respectively. The confidence intervals for Cmax were 0.81-1.12, 0.82-1.17 and 0.87-1.09 for R-, S-, and 5-OH-propafenone, respectively. The concentration maxima of both enantiomers were registered on average 15 min earlier after administration of the test preparation. This difference is of no clinical relevance. Both preparations are bioequivalent according to the criteria of the Committee for Proprietary Medicinal Products (CPMP).

Serum concentration of piroxicam and inhibition of platelet aggregation in patients with rheumatoid arthritis and M. Bechterew

An open trial was conducted in 22 in-patients with classic or definite rheumatoid arthritis (RA) and 17 in-patients with M. Bechterew with the aim to investigate the effect of increasing concentrations of piroxicam in vivo on the platelet aggregation in such patients. In all patients therapy with piroxicam (10 mg/d) was started after withdrawing other non-steroidal antiinflammatory drugs. In 36 cases the daily dose of piroxicam was increased to 20 mg/d and in five cases to 30 mg/d based on clinical judgment. The platelet aggregation in platelet-rich plasma (PRP) caused by epinephrine, ADP (both 5 microM) and collagen (2 micrograms/ml) was measured at the beginning of the trial and before each dose increase. The results of the trial suggest that a significant positive correlation exists between increasing serum concentrations of piroxicam and the degree of inhibition of platelet aggregation, caused by all three platelet aggregation agonists. This action of piroxicam was most pronounced when epinephrine was used as platelet agonist.

Differences in the bioavailability of dihydrotachysterol preparations

The bioavailability of four preparations containing dihydrotachysterol (DHT2) was tested in two separate trials with administration of single, oral doses of 1 mg per individual. The relative bioavailability of corresponding preparations (capsules vs capsules and oral solution vs oral solution) was tested in a randomised, cross-over pattern within the same group of volunteers. Two different groups of 24 healthy volunteers took part in each trial. Solution and capsule bioavailability was also compared inter-individually. A new sensitive HPLC-method (quantification limit 0.5 ng.ml-1) was used for the measurement of DHT2 concentration in serum. Three of the preparations tested had a similar bioavailability (mean AUC values of 195.5-223 ng.h.ml-1); the bioavailability of the fourth preparation (A.T.10 oral solution) was considerably lower (mean AUC value 111.5 ng.h.ml-1). The present dosage recommendations of all four preparations are identical. A new dosage recommendation is thus required for the oral solution with low bioavailability (A.T.10).

[Absolute bioavailability of chlorpromazine, promazine and promethazine]

The absolute bioavailability of the three phenothiazine neuroleptics, promazine (Sinophenin, CAS 58-40-2), chlorpromazine (Propaphenin, CAS 50-53-3) and promethazine (Prothazin, CAS 60-87-7) was tested in three single-dose cross-over studies. In each trial 12 to 14 healthy volunteers were enrolled. The single doses for promazine, promethazine and chlorpromazine were 100, 75 and 150 mg (orally) and 20, 50 and 50 mg (intravenously), resp. The serum concentrations of the three neuroleptics were measured by means of a selective HPLC-method. the distribution-free confidence intervals for the absolute bioavailability of the three phenothiazines were within 10.5 to 24.7% for chlorpromazine, 7.8 to 24.9% for promazine and 12.3 to 40% for promethazine. Promazine and chlorpromazine are pharmacokinetically very similar and differ substantially from promethazine.