Bioequivalence study of two morphine extended release formulations after multiple dosing in healthy volunteers

AIM

Two extended release (ER) formulations of morphine sulphate (30 mg each), Oramorph SR (test) and a marketed reference formulation (MST Mundipharma Retardtabletten), were investigated for their relative bioavailability at steady-state:

METHODS

The study was designed as a single-centre, open-label, two-period crossover, pharmacokinetic comparison in 28 healthy male volunteers and was completed in 23 subjects. The determination of morphine and its metabolite morphine-6-glucuronide in plasma was done by HPLC with electrochemical detection after solid-phase extraction.

RESULTS

Under steady-state conditions in the first dosing interval, mean maximum plasma concentrations for morphine were 19.1 ng/ml (CV% 41) for Oramorph SR 30 mg and 19.1 ng/ml (CV% 33) for MST-30 Mundipharma Retardtabletten. Geometric mean AUC(0-12) values were calculated as 108 ngxh/ml (CV% 40) for Oramorph SR 30 mg and as 118 ng x h/ml (CV% 30) for the reference formulation. The plasma concentrations of the major metabolite, morphine-6-glucuronide, were found to be generally in a higher range compared to the parent compound. The 90% confidence intervals of test to reference ratios calculated for all relevant parameters (AUC, C(max), PTF) for both the parent compound and morphine-6-glucuronide were all within the limits of 80 - 125%. The most frequent adverse events (AE > 10%) during Oramorph SR 30 mg treatment were headache (36%), dizziness (18%), nausea (21%), vomiting (21%) and pruritus (11%). During treatment with MST-30 Mundipharma Retardtabletten, the most frequent AEs were headache (29%), dizziness (13%), nausea (29%) and vomiting (29%).

CONCLUSION

The results demonstrate bioequivalence of Oramorph SR 30 mg and MST-30 Mundipharma Retardtabletten.

Effect of pimobendan on exercise capacity in patients with heart failure: main results from the Pimobendan in Congestive Heart Failure (PICO) trial

PRIMARY OBJECTIVE

To determine the effects of pimobendan 2.5 and 5 mg daily on exercise capacity in patients with chronic heart failure.

DESIGN

A randomised, double blind, placebo controlled trial of the addition of pimobendan to conventional treatment with a minimum follow up of 24 weeks.

SETTING

Outpatient cardiology clinics in six European countries.

PATIENTS

317 patients with stable symptomatic heart failure, objectively impaired exercise capacity, and an ejection fraction of 45% or lower who were treated with at least an angiotensin converting enzyme inhibitor and a diuretic and who tolerated a test dose of pimobendan.

RESULTS

Compared with placebo, both pimobendan 2.5 and 5 mg daily improved exercise duration (bicycle ergometry) by 6% (P = 0.03 and 0.05) after 24 weeks of treatment. At that time 63% of patients allocated to pimobendan and 59% of those allocated to placebo were alive and able to exercise to at least the same level as at entry (P = 0.5). No significant effects on oxygen consumption (assessed in a subgroup of patients) and on quality of life (assessed by questionnaire) were observed. Pimobendan was well tolerated. Proarrhythmic effects (24-hour electrocardiography) were not observed. In both pimobendan groups combined the hazard of death was 1.8 (95% confidence interval 0.9 to 3.5) times higher than in the placebo group.

CONCLUSIONS

Pimobendan improves exercise capacity in patients with chronic heart failure who are also on conventional treatment. The balance between benefit and risk of treatment with this compound remains to be established however.

[Dynamics of the hypnotic effect of 0.125 mg and 0.250 mg brotizolam. The lower dosage is adequate for treatment of sleep disorders]

BACKGROUND

Although observations have shown that half a tablet (0.125 mg) of brotizolam develops an adequate sedative effect in patients who cannot get to sleep, confirmatory pharmacodynamic studies are lacking.

METHOD

In a comparative double-blind, randomized, placebo-controlled study, the hypnotic effects of 0.125 mg and 0.250 mg brotizolam, a short-acting benzodiazepine-like hetrazepine, were investigated. The concept underlying the study was that both doses are equally rapid in action onset, but differ in duration of effect. The study included 49 healthy women aged between 23 and 44 years. The nocturnal tests lasted until 2.30 am, and a concluding examination took place after breakfast. The test subjects were asked to estimate their state of well-being on visual analog scales at half-hour intervals, while concentration was tested hourly using the digit symbol substitution test (DSST) tried and tested in numerous studies on benzodiazepines.

RESULTS

Both doses proved to be equally effective after 0.5, 1.5 and 2.5 hours. While the hypnotic effect of the lower dose no longer differed from that of placebo after 3.5 hours, the larger dose still had a greater effect than both placebo and the lower dose after 4.5 hours. A hangover effect in the morning was not observed with either dose. The pharmacodynamic results indicate that the effect of the substance is readily controllable, and that half a tablet of brotizolam is an effective treatment of difficulty in getting to sleep initially or after waking prematurely.

CONCLUSION

The results of the present study demonstrate for the first time that a half-tablet of brotizolam is an effective treatment of difficulty in getting to sleep initially or after premature wakening.

Nocturnal psychometric assessment of the hypnotic activity of low and normal doses of brotizolam

The hypnotic activity of acute doses of 0.125 mg and 0.250 mg brotizolam (CAS 57801-81-7, Lendormin) was compared in a double-blind randomised placebo-controlled study. Forty-nine healthy female volunteers aged between 23 and 44 years were enrolled. Trial medication was administered sublingually at 9:15 p.m. and 9:30 p.m., respectively. The nocturnal investigations continued until 2:30 a.m. A final examination was performed in the morning after breakfast. Every 30 min mood was measured by visual analogue scales. A computerised psychometric test (CDT) over 8 min was undertaken in order to measure continuous attention under short-term memory load. The Digit Symbol Substitution Test (DSST) was performed every hour. The CDT was not evaluable due to significant baseline differences. A statistically significant sedative effect in the DSST was already found 30 min after administration of 0.250 mg brotizolam, while the effect of 0.125 mg brotizolam just failed to reach the threshold of significance. Both treatments showed equivalent efficacy at 0.5, 1.5 and 2.5 h after administration. After 3.5 and 4.5 h there was no statistically significant difference between placebo and 0.125 mg brotizolam. After 4.5 h 0.250 mg brotizolam still showed significant hypnotic activity compared to placebo and 0.125 mg brotizolam. No treatment effects on mood were apparent according to the visual analogue scales. Furthermore, no hangover effects were detected for any of the parameters measured. The pharmacodynamic results confirmed the duration of action of more than 4.5 of h 0.250 mg brotizolam found in earlier studies and suggest that 0.125 mg is as effective as 0.250 mg with regard to sleep onset disturbances but has a shorter duration of action.