Action and use
Antibacterial.
DEFINITION
Nitrofurantoin Oral Suspension is a suspension of Nitrofurantoin in a suitable flavoured vehicle.
Nitrofurantoin Oral Suspension should not be diluted.
The oral suspension complies with the requirements stated under Oral Liquids and with the following requirements.
Content of nitrofurantoin, C8H6N4O5
90.0 to 110.0% of the stated amount.
IDENTIFICATION
A. The light absorption, Appendix II B, in the range 300 to 400 nm, of the final solution obtained in the Assay exhibits a maximum at 367 nm.
B. Dissolve 5 mg of the residue obtained by centrifuging a quantity of the oral suspension containing 50 mg of Nitrofurantoin in 5 mL of 0.1M sodium hydroxide. A deep yellow solution is produced, which changes to deep orange-red.
ASSAY
Carry out the following procedure in subdued light. To a weighed quantity containing 30 mg of Nitrofurantoin add, in successive small volumes, 50 mL of dimethylformamide, stirring well between each addition. Continue stirring until the
sample is completely dissolved and dilute to 500 mL with an aqueous solution containing 1.8% w/v of sodium acetate and 0.14% v/v of glacial acetic acid. Dilute 10 mL of this solution to 100 mL with the sodium acetate-acetic acid solution and
measure the absorbance of the resulting solution at the maximum at 367 nm, Appendix II B, using in the reference cell a 1% v/v solution of dimethylformamide in the sodium acetate-acetic acid solution. Calculate the content of C8H6N4O5
taking 765 as the value of A(1%, 1 cm) at the maximum at 367 nm. Determine the weight per mL of the oral suspension, Appendix V G, and calculate the content of C8H6N4O5, weight in volume.
STORAGE
Nitrofurantoin Oral Suspension should be protected from light.
