Stability of amoxicillin trihydrate-potassium clavulanate in original containers and unit dose oral syringes

The stability of reconstituted amoxicillin trihydrate-potassium clavulanate oral suspension both in original containers and pre-packaged in commercially available oral syringes stored at various temperatures was determined. Amoxicillin trihydrate 125 mg/5 mL-potassium clavulanate 31.25 mg/5 mL and amoxicillin trihydrate 250 mg/5 mL-potassium clavulanate 62.5 mg/5 mL were reconstituted according to the manufacturer's instructions. The reconstituted suspensions in the original containers and in five brands of oral syringes were stored at 5 degrees C and 25 degrees C and -10 degrees C, 5 degrees C, and 25 degrees C, respectively, for 0, 2, 4, 7, and 14 days. The concentrations of amoxicillin trihydrate and potassium clavulanate remaining after storage were assayed in triplicate by reverse-phase high-performance liquid chromatography, using a stability-indicating method. An F statistic was calculated to determine whether different syringe brands had significantly different effects on drug stability. Amoxicillin trihydrate was stable for at least 10 days in the original containers and all types of oral syringes at 5 degrees C. However, potassium clavulanate was stable for 11.1 days in original containers and less than 5 days in all types of oral syringes at 5 degrees C. The effect of syringe brand on the stability of drugs over time at specific storage conditions and temperature was significant for potassium clavulanate at 5 degrees C and for both amoxicillin trihydrate and potassium clavulanate at 25 degrees C. The manufacturer's guidelines for storage of reconstituted amoxicillin trihydrate-potassium clavulanate oral suspension in the original containers should not be applied to dosages repackaged in unit dose oral syringes.

Therapeutic dosing of pralidoxime chloride

Pralidoxime chloride is a useful agent in the treatment of organophosphate poisoning. Poisindex, a widely used poisoning treatment resource, recommends dosing pralidoxime chloride as an intermittent iv infusion every 8-12 hours, whereas other authors have used continuous iv infusion with good results. Available animal data suggest that a serum concentration of 4 micrograms/ml may be a minimal level to protect against the toxic effects of organophosphates. Pharmacokinetic simulations, based on parameters obtained from healthy nonpoisoned subjects, show that pralidoxime levels fall rapidly to less than 4 micrograms/ml within 1.5-2 hours after a 1-g iv bolus. Continuous iv infusion (0.5 g/h) maintains pralidoxime levels greater than 4 micrograms/ml throughout the length of infusion. We conclude that continuous iv infusion of pralidoxime chloride may be the preferred method of administration in patients with acute organophosphate poisoning. Clinical trials will be necessary to document the effectiveness of this regimen.

Pharmacokinetics of single-dose oral ciprofloxacin in patients undergoing chronic ambulatory peritoneal dialysis

The prevention and treatment of peritonitis in patients undergoing peritoneal dialysis is often complicated by several factors, including nephrotoxicity, requirement for hospitalization, parenteral antibiotic therapy, and infection caused by resistant microorganisms. Ciprofloxacin, a new carboxyquinolone derivative, may offer the advantages of oral administration, a broad spectrum of antibacterial activity, and safety for the management of these patients. The pharmacokinetics of ciprofloxacin in serum and peritoneal fluid of eight adult patients undergoing chronic ambulatory peritoneal dialysis (CAPD) were investigated. Each patient ingested a single 750-mg dose of ciprofloxacin, and drug concentrations were measured by high-pressure liquid chromatography in serum and peritoneal fluid for 48 h after the dose. Serum concentrations reached a mean peak of 3.6 micrograms/ml 1 to 2 h after the oral dose. The mean terminal serum half-life was 16.8 h, and the mean peritoneal fluid/serum concentration ratio was 0.64. The mean peak ciprofloxacin concentration in peritoneal fluid was 1.3 micrograms/ml, and the bioactivity of the drug in peritoneal fluid was confirmed. These data indicated that therapeutic concentrations of ciprofloxacin against bacterial pathogens commonly associated with peritonitis in CAPD patients may be achievable in the peritoneal fluid after oral administration to patients undergoing CAPD. In addition, the pharmacokinetic data provide guidelines for further clinical studies of oral ciprofloxacin in CAPD patients.