Edition: BP 2025 (Ph. Eur. 11.6 update)
Diazepam Rectal Solution
General Notices
Action and use
Benzodiazepine.
DEFINITION
Diazepam Rectal Solution is a solution of Diazepam in a suitable vehicle.
The rectal solution complies with the requirements stated under Rectal Preparations and with the following requirements.
Content of diazepam, C16H13ClN2O
95.0 to 105.0% of the stated amount.
IDENTIFICATION
A. The light absorption, Appendix II B, of the solution obtained in the Assay exhibits a maximum at 368 nm. B. Carry out the method for thin-layer chromatography, Appendix III A, using silica gel G as the coating substance and a mixture of 10 volumes of methanol and 100 volumes of chloroform as the mobile phase. Apply separately to the plate 10 µL of each of the following solutions. For solution (1) dilute a suitable volume of the rectal solution with sufficient methanol to produce a solution containing 0.10% w/v of Diazepam. Solution (2) contains 0.10% w/v of diazepam BPCRS in methanol. After removal of the plate, spray it with a 10% v/v solution of sulfuric acid in absolute ethanol, heat at 105° for 10 minutes and examine under ultraviolet light (365 nm). The principal spot in the chromatogram obtained with solution (1) corresponds to that in the chromatogram obtained with solution (2).
TESTS
Acidity or alkalinity
pH, 6.2 to 7.2, Appendix V L.
ASSAY
To a volume containing 10 mg of Diazepam add 20 mL of mixed phosphate buffer pH 7.0 and extract with four 20 mL quantities of chloroform, passing each extract through the same 5 g of anhydrous sodium sulfate. Combine the chloroform extracts, dilute to 100 mL with chloroform and mix. Evaporate 10 mL to dryness in a current of nitrogen, dissolve the residue in 25 mL of 0.05M methanolic sulfuric acid, mix and measure the absorbance of the resulting solution at the maximum at 368 nm, Appendix II B. Calculate the content of C16H13ClN2O taking 151 as the value of A(1%, 1 cm) at the maximum at 368 nm.
STORAGE
Diazepam Rectal Solution should be protected from light.
