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  • HPLC analysis of indomethacin and its impurities in capsule and suppository formulations.

HPLC analysis of indomethacin and its impurities in capsule and suppository formulations.

Journal of pharmaceutical sciences (1982-07-01)
E Kwong, G K Pillai, K M McErlane
ABSTRACT

Indomethacin and its impurities in suppository and capsule formulations were quantitatively determined by HPLC using a reversed-phase, octadecyl column and a mobile phase of methanol-water-acetonitrile-acetic acid (55:35:10:1). Analysis of the suppository formulations provided a mean potency for indomethacin of 103.8%. The same formulation was found to contain 4-chlorobenzoic acid (0.02%), 5-methoxy-2-methyl-3-indoleacetic acid (0.07%), 4-chlorobenzoic acid-alpha-monoglyceride (0.39%), and indomethacin-alpha-monoglyceride (0.9%) as impurities. The latter two impurities were a result of the interaction of indomethacin and 4-chlorobenzoic acid with glycerin used in the suppository base. Capsule formulations were likewise assayed with an average potency of 99.9 and 101.5% for 25- and 50-mg dosage forms, respectively. Only one of the two capsule formulations examined contained detectable quantities of 4-chlorobenzoic acid (0.05%).

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
5-Methoxy-2-methyl-3-indoleacetic acid, 98%