Archive for October, 2010
Posted by James
Regression analysis of the peak area ratio of nitrofurantoin to internal standard versus concentration demonstrated linearity over the working range of the concentrations, with coefficients of determination (r2) greater than 0.999 (n = 4). The intraday (n = 4) and interday (n = 4) coefficients of variation for the 3 different concentrations were within acceptable limits: 0.06% and 0.30%, respectively, for the 0.25 mg/mL suspension; 0.06% and 0.13%, respectively, for the 1.00 mg/mL suspension; and 0.20% and 0.09%, respectively, for the 2.00 mg/mL suspension.
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Posted by James
Degradation of Nitrofurantoin
Nitrofurantoin 2.00 mg/mL was incubated overnight at 40°C, exposed to daylight at room temperature for 7 days, and then boiled for 1 min. The sample was then cooled to room temperature. A 0.5-mL aliquot was mixed with 0.5 mL furazolidone 2.00 mg/mL, the mixture was filtered, and a 10-pL sample was injected onto the column. The chromatogram obtained for the degraded preparation was compared with a chromatogram obtained from a standard (1.00 mg/mL) to determine any changes in concentration, retention time, and peak shape.
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Posted by James
Preparation of Suspensions
Nitrofurantoin suspensions (10 mg/mL) were prepared by crushing commercially available nitrofurantoin 50-mg tablets (Apotex Inc, Weston, Ontario, lot GE3153) and resuspending the powder in a 1:1 mixture of Ora-Sweet and Ora-Plus (Paddock Laboratories Inc, lots 4140869 and 4040385, respectively). Six replicates were prepared in separate 50-mL amber plastic prescription bottles (Richards Packaging Inc, RIGO Products Division, Gloucester, Ontario; polyvinyl chloride [recycle code 3]). Three of the bottles were stored at 4°C (refrigerated) and 3 at 25°C (room temperature). All bottles were exposed only to fluorescent light in the laboratory.
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Posted by James
INTRODUCTION
Nitrofurantoin, an antibacterial agent used in the treatment of urinary tract infections, is commonly prescribed for children and elderly adults who are unable to swallow tablets or capsules. An oral suspension is available in the United States, but only tablets and capsules are commercially available in Canada. As such, Canadian pharmacists must prepare the suspensions extemporaneously.
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