Some studies on the preservation of indometacin suspensions intended for ophthalmic use

Suspensions of indometacin (1% w/v), buffered to pH 5.6, may be satisfactorily preserved by 0.002% w/v phenylmercuric nitrate in the presence of hydroxypropylmethylcellulose (0.5% w/v), despite 90% of the preservative being adsorbed to the indometacin powder. Polyvinyl alcohol (1.4%) could be used as an alternative suspending agent.