Basic and clinical studies on the efficacy of grepafloxacin on respiratory infectious disease

A new quinolone antimicrobial drug, grepafloxacin (GPFX), was studied basically and clinically, with the following results: 1. Antibacterial activity: Minimum inhibitory concentrations (MICs) of the drug against 515 strains of 16 clinically isolated species were determined, and compared with those of three other drugs, ciprofloxacin (CPFX), norfloxacin (NFLX) and ofloxacin (OFLX). GPFX was found to have the best antimicrobial activity for gram-positive bacteria among the drugs tested. Its antimicrobial activity against gram-negative bacteria was approximately equal to that of CPFX, and superior to NFLX and OFLX. 2. Concentrations of GPFX in blood and sputum: The concentrations of GPFX in blood and sputum were determined by high-performance liquid chromatography in 4 patients with chronic respiratory tract infection. The maximum blood level reached 0.20~1.63 μg/ml and the maximum sputum level 0.70~4.02 μg/ml at 3~4 hours and 5-6 hours after oral administration of 300 mg and 200 mg, respectively. The penetration rate into sputum was 235.5~371.4%. 3. Clinical study: GPFX was administered to 17 patients with respiratory tract infection, and the clinical and bacteriological efficacy and side effects were investigated. GPFX was excellent in 2 patients, good in 10, poor in 4 and unevaluable in 1. The overall efficacy rate was 75.0%. Eight of the 12 strains isolated from 10 patients were eradicated, showing a 66.7% eradication rate. Although none of the patients had side effects, elevation of transient Al-P or transient eosinophilia was observed in two patients on clinical laboratory tests.