Long-acting isosorbide mononitrate

Obtaining and Characterization of a Polydisperse System Used as a Transmembrane Carrier for Isosorbide Derivatives

Due to their effect of vasodilatation, isosorbide nitrates represent one of the most important and most used solutions for angina pectoris. Unfortunately, these compounds have multiple dose-related adverse drug reactions such as headache, weakness, mild dizziness, and occasionally heart rate changes, nausea, vomiting, and sweating. The main aims of this research were to obtain and to evaluate new polyurethane (PU) structures that can be used as a proper transmembrane carrier with an improved release kinetic. Chitosan-based PU structures were obtained by a polyaddition process between hexamethylene diisocyanate and a mixture of chitosan, butanediol, and polyethylene glycol in the presence of caffeine as a synthesis catalyst. The obtained samples (with and without isosorbide nitrates) were characterized regarding the encapsulation and release rate (UV-Vis spectra), chemical composition (FTIR), thermal stability (thermal analysis), morphology changes (SEM and SANS), and in vivo irritation tests. These methods revealed no significant differences between the two sample structures. Multipopulational structures with sizes between 73 and 310 nm, with an increased tendency to form clusters and a high resistance to heat (up to 280°C), were obtained. This study presents an alternative administration of isosorbide derivatives based on a PU carrier with a high biocompatibility and a prolonged release.

Pharmacokinetic profile of a new controlled-release isosorbide-5-mononitrate 60 mg scored tablet (Monoket Multitab)

The influences of food, tablet splitting, and fractional dosing on the pharmacokinetics of a new controlled-release double-scored tablet containing 60 mg isosorbide-5-mononitrate (Monoket Multitab) were investigated in healthy male volunteers. Food interaction was evaluated after single dose administration under fasted conditions and after a standard high-fat breakfast. The effect of tablet splitting was assessed at steady-state, after 5 days of once daily dosing with the tablet taken intact or trisected. The influence of fractional dosing was assessed after 1 and 6 days of daily regimen of 40 mg in the morning (2/3 of a tablet) and 20 mg in the evening (1/3 of a tablet). The pharmacokinetics of isosorbide-5-mononitrate after taking the tablet intact or in three fragments were very similar with a mere 10% increase of maximum plasma concentration (C(max)) for the latter, while the time to peak (T(max)) decreased from 5 to 4 h and areas under the concentration vs. time curves (AUCs) were virtually unchanged. Morning trough concentration reached 53 and 46 ng/ml, respectively. Administration of the intact tablet after a high-fat breakfast increased C(max) by 18% and AUC by 21%, and slightly delayed T(max) from 5 to 6h. During fractional dosing, morning and evening C(max) reached 364 and 315 ng/ml on the first day, and 373 and 300 ng/ml on the 6th day, respectively. The ratio of AUC(0-24 h) on the last day to AUC(infinity) on the first day, was 82.1% (confidence limits 71.7-94.1%) possibly resulting from peripheral volume expansion. The release characteristics of Monoket Multitab are thus moderately influenced by concomitant intake of food and to a very minor extent by tablet breaking. Fractional dosing allows to achieve lower peak and higher morning trough levels, while total exposure is comparable to that during once daily dosing (AUC(0-24 h, s.s.) of 5.55+/-1.78 and 5.71+/-1.08 microg h/ml).