Simultaneous GLC analysis of aspirin and nonaspirin salicylates in pharmaceutical tablet formulations

The analysis of aspirin and nonaspirin salicylates in buffered and plain tablet formulations employing nearly nonaqueous extraction is described. The results obtained compare favorably with those obtained from USP procedures. A simultaneous assay for aspirin and nonaspirin salicylates in buffered tablets involves the use of an acidified chromatographic siliceous earth column for the separation of the aspirin and nonaspirin salicylates from various buffers or antacids. The methods described here have definite advantages over USP XX procedures, and the buffered aspirin tablet procedures also is adaptable to aspirin formulations containing codeine, acetaminophen, propoxyphene, caffeine, and many antihistamines.