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Nystatin                                                    1400-61-9

Category Antifungal.

      Nystatin is a mixture of antifungal polyenes produced by the growth of certain strains of Streptomyces noursei. It consists largely of nystatin A1. It contains not less than 4400 Units per mg and not more than 5000 Units per mg.

Description Yellow to light brown powder; hygroscopic.

Solubility Very slightly soluble in water; sparingly soluble in chloroform, in ethanol, in ether, and in methanol.

Warning

      1. High dose may cause nausea, vomiting, gastrointestinal distress, diarrhea, urticaria and rarely the Stevens-Johnson syndrome.

      2. Because it is not absorbed from the gastrointestinal tract, it is not suitable for the treatment of systemic fungal infections.

Packaging and storage Nystatin shall be kept in tightly closed containers, protected from light, and stored at a temperature between 2º and 8º.

Labelling The label on the container states (1) number of Units per mg; (2) storage condition.

Identification

      A. The infrared absorption spectrum is concordant with the spectrum obtained from Nystatin RS (Appendix 2.1) or with the reference spectrum of Nystatin.

      B. Dissolve 100 mg in a mixture of 5.0 ml of glacial acetic acid and 50 ml of methanol and dilute to 100 ml with methanol, dilute 1 ml of this solution to 100 ml with methanol. The ultraviolet absorption spectrum of the resulting solution, when immediately observed between 220 and 350 nm, exhibits four maxima at 230 nm, 291 nm, 305 nm and 319 nm, and a shoulder at 280 nm. The ratios of the absorbance at the maxima at 291 nm and 319 nm to the absorbance at the absorption maximum at 305 nm are 0.61 to 0.73 and 0.83 to 0.96, respectively. The ratio of the absorbance measured at the maximum at 230 nm to that measured at the shoulder at 280 nm is 0.83 to 1.25 (Appendix 2.2).

      C. To 2 mg add 2 drops of hydrochloric acid: a brown colour develops.

pH 6.5 to 8.0, in a 3.0 per cent w/v suspension in water (Appendix 4.11). 

Loss on drying Not more than 5.0 per cent w/w after drying at 60º at a pressure not exceeding 0.7 kPa (about 5 Torr) for 3 hours (Appendix 4.15).

Sulfated ash Not more than 3.5 per cent w/w (Appendix 5.3).

Assay Carry out the microbiological assay of Nystatin according to the “Microbiological Assay of Antibiotics” (Appendix 6.10).