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Category Antibacterial.

      Erythromycin Ethylsuccinate for Oral Suspension is a dry mixture of Erythromycin Ethylsuccinate with one or more suitable buffers, colour, diluents, dispersants, and flavours. It contains the equivalent of not less than 90.0 per cent and not more than 120.0 per cent of the labelled amount of C₃₇H₆₇NO₁₃.

Strengths available 200 and 400 mg per 5 ml (base).

Dose Adults: 400 mg every 6 hours or 800 mg every 12 hours. The maximum total dose should not exceed 4 g per day.

      Children: 7.5 to 12.5 mg per kg of body weight every 6 hours or 15 to 25 mg per kg of body weight every 12 hours.

      Severe infections: 15 to 25 mg per kg of body weight every 6 hours.

Contra-indication; Warning; Precaution See under Erythromycin, p. 99.

Additional information After constitution, Erythromycin Ethylsuccinate for Oral Suspension does not require refrigeration if used within 14 days.

      See also under Erythromycin Ethylsuccinate, p. 103.

Packaging and storage Erythromycin Ethylsuccinate for Oral Suspension shall be kept in tightly closed containers. After constitution, it should be used within the period stated on the label.

Labelling The label on the container states the quantity equivalent to the amount of erythromycin.

Identification

      A. Dilute a quantity of the oral suspension containing the equivalent of 100 mg of erythromycin to 25 ml with water and extract with two 10-ml portions of dichloromethane. Wash the combined extracts with five 10-ml quantities of water, filter using silicone-treated filter paper (Phase Separator paper is suitable) and evaporate to dryness. The infrared absorption spectrum of the residue after drying at 105º for 15 minutes is concordant with the spectrum obtained from Erythromycin Ethylsuccinate RS (Appendix 2.1) or with the reference spectrum of Erythromycin Ethylsuccinate.

      B. Carry out the test as described in the “Thin-layer Chromatography” (Appendix 3.1), using silica gel  G as the coating substance and a mixture of 17 volumes of methanol and 3 volumes of chloroform as the mobile phase but developing the chromatogram in an unlined chromatographic chamber. Apply separately to the plate, 10 μl of each of the following solutions. For solution (A), add a volume of methanol to a portion of the oral suspension, sufficient to yield a solution containing the equivalent of 2.5 mg of erythromycin per ml, and stir for 30 minutes. Centrifuge a portion of this mixture, and use the clear supernatant liquid. Solution (B) contains 3 mg per ml of Erythromycin Ethylsuccinate RS in methanol. After removal of the plate, allow it to dry in air. Spray the plate with a mixture of 18 volumes of absolute ethanol, 1 volume of 4-methoxybenzaldehyde and 1 volume of sulfuric acid. Heat the plate at 100º for 10 minutes. Erythromycin and succinic acid moieties appear as black-to-purple spots. The principal spots in the chromatogram obtained from solution (A) correspond to those obtained from solution (B).

pH 6.5 to 9.5, in the suspension constituted as directed in the labelling (Appendix 4.15).

Loss on drying Not more than 1.0 per cent w/w after drying about 100 mg in a capillary-stoppered bottle at 60º at a pressure not exceeding 2.7 kPa (about 20 Torr) for 3 hours (Appendix 4.15).

Assay Constitute Erythromycin Ethylsuccinate for Oral Suspension as directed in the labelling. Proceed as directed in the microbiological assay of Erythromycin according to the “Microbiological Assay of Antibiotics” (Appendix 6.10), using an accurately measured volume of the oral suspension, freshly mixed and free from air bubbles, blended for 4±1 minutes in a high-speed glass blender jar with sufficient methanol  to give a stock solution containing the equivalent of about 1 mg of erythromycin per ml.

Other requirements Comply with the requirements described under “Oral Liquids” (Appendix 1.16).