Pharmacokinetics and pharmacodynamics of ritodrine hydrochloride administered orally and intramuscularly to female healthy volunteers.

Ritodrine hydrochloride ((R,S)-4-hydroxy-alpha-[1-[2-((4-hydroxyphenyl)ethyl]amino)ethyl]benzenemethanol, CAS 26652-09-5) is a direct-acting sympathomimetic agent with a predominant beta-adrenergic activity and a selective action on beta2-receptors. A clinical trial was carried out to investigate the pharmacokinetics, pharmacodynamics and safety of ritodrine hydrochloride administered at the doses of 10, 20 and 30 mg p.o. and 10 mg by i. m. route. A four-way randomised crossover design was adopted on 12 healthy female volunteers with a wash-out of at least 14 days. Concentrations of ritodrine and of the pool of ritodrine in plasma and concentrations of the pool of ritodrine in urine of volunteers were bioassayed with tandem mass spectrometry. The following pharmacokinetic parameters were calculated, using the non-compartmental model: Cmax, AUC0-t, AUC0-INF, t1/2, Vd/f, and Aet after each administration. The distribution volume of ritodrine proved to be about 3 times higher than that of the pool of ritodrine after i. m. injection, confirming the good permeability of ritodrine that massively enters tissue compartments. Statistical analyses of pharmacokinetic parameters ascertained that the p. o. absorption of ritodrine hydrochloride was linearly related with the doses administered in the 10-30 mg range. The pharmacodynamic parameters evaluated complied with the mechanism of action of this drug.

Pharmacokinetics of isoxsuprine hydrochloride administered orally and intramuscularly to female healthy volunteers.

Isoxsuprine (1-(4-hydroxyphenyl)-2-(1-methyl-2-phenoxyethylamino)-1-propanol, CAS 395-28-8) is a peripheral vasodilator that also stimulates beta-adrenergic receptors. It causes a direct relaxation of vascular and uterine smooth muscles and produces positive inotropic and chronotropic effects. It is widely used to arrest premature labour and miscarriage. The aim of this trial was to investigate the pharmacokinetics of isoxsuprine hydrochloride administered orally to healthy young female volunteers as an extended-release formulation at the doses of 30, 60 and 90 mg compared to 10 mg by i.m. route. A randomised, crossover, four-period, multisequence, single-dose design was adopted. Plasma and urine concentrations of free and total isoxsuprine were evaluated by tandem mass spectrometry that reached a low quantification limit of 1 ng/ml. From plasma concentrations Cmax, tmax, AUC(0-t), AUC(0-infinity), t1/2 and Vd and from urine concentration CUE(0-24h) were evaluated by the non-compartmental model. The free drug was present only in plasma after i.m. route, whereas total isoxsuprine, namely the drug after an enzymatic hydrolysis of the conjugate form, was detected in all plasma and urine samples. The distribution volume of the free drug proved to be 2.5 times higher than that of total isoxsuprine, which indicates a good penetration of the free drug into tissue compartments. Oral absorption was evaluated from the p.o./i.m. percentualized ratio of AUC and CUE and proved to be on average around 51%, being linearly correlated with the three doses administered. The oral absorption proved to be sustained as expected from the zero-order kinetics of the drug release from the core of the extended-release formulation. This has justified different values of half-life that was on average 2.2 h after the i.m. route and around 10 h after the three oral doses. After isoxsuprine administration, both oral and i.m. routes, the heart rate increased from baseline during the 9 h monitoring period. This was an expected finding attributable to the stimulating activity of beta-adrenergic receptors. The tolerability of isoxsuprine proved to be very good with all the four administrations performed.

Safety and tolerability of ribosome-component immune modulator in adults and children.

Ribosomal preparations (ribosome-component immune modulators [RCIMs]) do not contain attenuated bacteria and, in contrast to live bacterial extracts, which may induce severe side effects, retain immune stimulating activity without infectious capability. This study was designed to profile the tolerability of RCIM by reviewing narratively all randomized, double-blind, placebo-controlled clinical trials and open-label studies as well as data from postmarketing surveillance studies representing >30 million prescriptions. In the various clinical trials, RCIM tolerability in terms of clinical and laboratory parameters was good. There were no significant differences between patients receiving active treatment or placebo in a survey of tolerability results from randomized, double-blind, placebo-controlled studies. Pharmacovigilance analysis does not show a change in the risk profile of RCIM. The only contraindication was correlated with known hypersensitivity to any of the product components. RCIM should not be used in case of acute streptococcal glomerulonephritis, acquired immune deficiency syndrome, severe viral disease, or severe autoimmune disease. Risk associated with the use of RCIM is negligible in recurrent upper and lower airway infections in selected populations, such as children and elderly people.