Molecular mass distribution of sodium alginate by high-performance size-exclusion chromatography.

A sensitive high-performance size-exclusion chromatography (HPSEC) method with simple UV detection was developed for the molecular mass analysis of sodium alginate. It was used to evaluate alginates of varying molecular mass and the results were compared with the viscosity measurements. This HPSEC method was sensitive to serve as the stability indicating method for alginate after storage under different conditions. The information of relative molecular mass distribution of alginate was provided with reference to pullulan molecular mass standards. The comparison of the HPSEC chromatograms of alginate, pullulan and dextran revealed the effect of chemical composition of a polysaccharide and its effect on apparent molecular mass distribution.

Pharmacokinetics and safety of single rising doses of ofloxacin in healthy volunteers.

The pharmacokinetics, safety, and disposition of the new antimicrobial fluoroquinolone ofloxacin were evaluated after oral administration in 14 healthy, male volunteers in a double-blind, placebo-controlled study. Ofloxacin was administered as 100-, 300-, and 600-mg doses separated by 1 week. Plasma and urine concentrations after each administration were measured using a sensitive and specific high-performance liquid chromatographic procedure. The distribution of ofloxacin was modeled using a two-compartment open-body model with first-order absorption. Maximum plasma concentrations and area under the plasma concentration versus time curve increased in a linear, dose-proportional manner over the range studied. At all levels, within 36 hours after administration, approximately 70% of the dose was recovered in urine as unchanged ofloxacin and only minimal amounts (less than 4%) as metabolites. No significant changes in the distribution or elimination of the compound were found over the 6-fold dose range. No major laboratory toxicities or clinically significant adverse effects were noted in either the ofloxacin or placebo group.

The bioavailability of ofloxacin from several formulations.

The bioavailability of ofloxacin after a single dose of one of two tablet formulations (200 or 400 mg) or a liquid formulation (1.67 mg/ml) was investigated in 24 healthy male volunteers in an open randomized, crossover design study with a 5-day wash-out period between doses. Plasma concentrations of ofloxacin were determined at various times after administration by a sensitive and specific High Pressure Liquid Chromatography (HPLC) method. Ofloxacin was well absorbed after each administration, although somewhat more slowly after the tablet formulations than the solution. Mean AUC values of 31.8, 31.3, and 31.3 micrograms.hr/ml were calculated after administration of the solution, 2 x 200 mg tablets and a 400 mg tablet, respectively. Thus, the bioavailability of the tablets was in excess of 98% that of the liquid reference. Mean Cmax values of 4.4, 3.7 and 3.7 micrograms/ml were observed at Tmax values of 0.8, 1.6 and 1.8 hours after administration of the solution, 2 x 200 mg tablets and a 400 mg tablet, respectively. The drug was well tolerated and no adverse effects necessitating subject withdrawal were noted during the study.

The effect of food or milk on the absorption kinetics of ofloxacin.

We have studied the effects of food or milk on the absorption of ofloxacin in 21 healthy male volunteers in a three-way crossover design. Milk did not alter the rate or extent of absorption of ofloxacin or its elimination. Food altered the onset and/or rate of absorption, but not the extent of absorption or the elimination rate. Thus, food reduced peak ofloxacin concentrations (Cmax) by 20% compared with fasting conditions and the time to reach maximum concentration (tmax) was prolonged on average by 1 h. However, the extent of absorption and the half-life (t 1/2) of ofloxacin were the same after each treatment. These data indicate that food and milk have a clinically insignificant effect on ofloxacin absorption.

Safety of multiple doses of ofloxacin in healthy volunteers.

A safety profile of ofloxacin, a new fluoroquinolone antibiotic, was assessed in twelve healthy male volunteers. Ofloxacin was dosed at 400 mg twice daily over a 10-day course of treatment. This evaluation included chemistry and haematologic profiles, neurologic evaluations, ophthalmologic examinations, audiometric testing, and electrocardiogram before, during and the end of the study. In addition, plasma samples were analysed for ofloxacin prior to each morning dose and a complete plasma concentration profile was performed on day 6. Gastrointestinal complaints such as nausea, diarrhoea and upset were the most frequent side effects reported. The only other adverse event that occurred in more than one volunteer was headache. None of the subjects in this study developed a serious side effect and no physical or psychological changes were observed. Laboratory values remained in their normal ranges with the exception of one volunteer who developed a 3-fold rise in one liver function test at the end of the study. The subject was asymptomatic and this aberration resolved without sequelae. In summary, a 10-day course of ofloxacin was found to be safe and have a low potential for toxicity. The side effects observed in this study were mild and similar to those observed with other fluoroquinolones.

Clinical experience with ofloxacin in sexually transmitted disease.

Experience with ofloxacin in the United States in the treatment of sexually transmitted diseases is reviewed. In one study, a single oral dose of either 400 mg or 600 mg eradicated Neisseria gonorrhoeae in all 43 evaluable patients. In another multicenter study a seven-day course of ofloxacin 300 mg b.i.d. was as effective as a seven-day course of doxycycline 100 mg b.i.d. in eradicating N. gonorrhoeae, Chlamydia trachomatis and, in men, Ureaplasma urealyticum. Because of increasing problems with antimicrobial resistance, particularly among strains of N. gonorrhoeae, ofloxacin, with its unique mechanism of action, and its broad spectrum activity against pathogens, may prove useful in the treatment of sexually transmitted diseases.