Separation of cyclobenzaprine from biological samples and its determination by thin-layer chromatography followed by densitometry

A sensitive method for the determination of cyclobenzaprine in biological samples is described. The extraction procedures used are different for urine and blood serum. The pH is a very important factor affecting the purity of the extract and the reproducibility of the recovery data, particularly for urine. By means of extraction, purification is achieved, while separation by thin-layer chromatography increases the specificity of the determination considerably. With a Vitatron TLD-100 densitometer, the substances separated can be measured as fluorescent spots from the thin-layer plates directly and quantitatively, with good reproducibility. The sensitivity is 1 ng and a linear relationship was obtained between 1 and 25 ng. extensive recovery studies were made in view of the forthcoming clinical evaluation of cyclobenzaprine. A number of experiments showed that this method has so far produced better results than can be obtained with the most sensitive gas chromatographic detection methods.