Sparfloxacin

Sparfloxacin is a broad-spectrum antibacterial that works by blocking two bacterial enzymes, DNA gyrase and topoisomerase IV, which kills many of the bacteria that infect the airways and lungs. A large number of clinical trials have shown it to be safe and effective for treating bacterial infections. In laboratory tests, it works better than other fluoroquinolones against some gram-positive organisms such as Streptococcus pneumoniae and Staphylococcus aureus, and also against Mycobacteria and Chlamydia spp.

Absorption

Quinoflox is well absorbed when taken by mouth, with an absolute oral bioavailability of 92%. After a single 400 mg oral dose, the mean maximum plasma sparfloxacin concentration was about 1.3 (±0.2) µg/mL, and the area under the curve was about 34 (±6.8) µg·hr/mL. A loading dose double the daily dose brings the plasma concentration to a steady state on the first day. For a 200 mg dose, peak plasma levels come between 3 and 6 hours after taking it, with the average at about 4 hours. Food and milk, including high-fat meals, do not affect how well sparfloxacin is absorbed. Antacids containing magnesium hydroxide and aluminium hydroxide, however, can cut its oral bioavailability by as much as 50%.

Distribution

Once in the general circulation, Quinoflox spreads well through the body, as shown by its large mean steady-state volume of distribution (Vdss) of 3.9 (±0.8) L/kg. Only about 45% of sparfloxacin binds to plasma proteins in serum, so it is not heavily held in the blood. It also passes well into body fluids and tissues. Studies of tissue and body fluid levels showed that oral doses give sustained concentrations, and that levels in the lower respiratory tract tissues and fluids are generally higher than in the plasma. Between 2 and 6 hours after a standard oral dose, the concentration in respiratory tissues (pulmonary parenchyma, bronchial wall and bronchial mucosa) was about 3 to 6 times that in the plasma, and these levels keep rising for up to 24 hours. Sparfloxacin is also highly concentrated in alveolar macrophages compared with plasma. The mean pleural effusion to plasma concentration ratios were 0.34 at 4 hours and 0.69 at 20 hours after the dose.

Metabolism

The liver breaks down Quinoflox, mainly through phase II glucuronidation, forming a glucuronide conjugate. This process does not use or interfere with cytochrome-mediated oxidation, particularly cytochrome P450.

Excretion

The total body clearance of Quinoflox is 11.4 (±3.5) L/hr and its renal clearance is 1.5 (±0.5) L/hr. Sparfloxacin leaves the body in both faeces (50%) and urine (50%). In people with normal kidney function, about 10% of an oral dose is passed in the urine as unchanged drug.