An on-line semi-automated solid-phase extraction procedure for high-performance liquid chromatographic determination of lonidamine in serum

Recent studies on lonidamine, the lead compound of the antispermatogenic indazol-carboxylic acids

Lonidamine (LND) or [1-(2,4-dichlorobenzyl)-1H-indazole-3-carboxylic acid] is an anticancer and an antispermatogenic drug whose mechanism of action is still incompletely understood. LND is effective against a number of tumors, including head, neck and breast cancers, probably because of the inhibition of mitochondrial electron transport and the enzyme hexokinase and to the induction of apoptosis. Instead, the antispermatogenic activity of LND appeared to be related not only to its energolytic activity but also to other effects activities such as the inhibition of specific chloride channels in the epididymis and the disruption of the inter-Sertoli-germ cell junctions, leading to premature release of germ cells. In addition, we recently reported that, in the rat, LND at the dose of 100 mg/Kg b.w. p.o., a fully active but well tolerated dose, caused specific changes of the testicular and epididymal macroglobulins (alpha(2)-macroglobulin, alpha(1) inhibitor-3 and alpha(1)-macroglobulin). Further studies are needed to elucidate the mechanism of action of LND, the lead compound of an interesting class of antispermatogenic drugs based on the core structure of 1-(2,4-dichlorobenzyl)-indazole-3-carboxylic acid.

Analysis of lonidamine in rat serum and testis by high performance liquid chromatography

A HPLC method for the determination of lonidamine in serum and testis, suitable for pharmacological studies in the rat and other mammals, has been developed. Briefly, 0.5 mL of serum or about 0.2 g of testicular tissue were extracted with ethyl acetate and evaporated to dryness under nitrogen. The residue was redissolved in methanol and an aliquot was injected onto a C18 column eluted with a mobile phase consisting of acetonitrile:water (51:49, v/v), containing 0.1% trifluoroacetic acid. The eluate was monitored at 230 nm with a sensitivity of 0.05 AUFS. By this method, the pharmacokinetics and the serum and testicular levels of the drug up to 120 h after the administration of one single dose (100 mg/kg body weight) of lonidamine to Sprague-Dawley rats have been studied. Results were highly variable, as previously reported, but a very good linear correlation was found between the serum and the testicular levels, suggesting that, in the rat, and possibly in the human, testicular levels could be estimated based on the serum concentrations.

Automating solid-phase extraction: current aspects and future prospects

This paper reviews current trends and techniques in automated solid-phase extraction. The area has shown a dramatic growth the number of manuscripts published over the last 10 years, including applications in environmental science, food science, clinical chemistry, pharmaceutical bioanalysis, forensics, analytical biochemistry and organic synthesis. This dramatic increase of more that 100% per year can be attributed to the commercial availability of higher throughput 96-well workstations and extraction plates that allow numerous samples to be processed simultaneously. These so-called parallel-processing workstations represent the highest throughput systems currently available. The advantages and limitations of other types of systems, including discrete column systems and on-line solid-phase extraction are also discussed. Discussions of how automated solid-phase extractions can be developed, generic approaches to automated solid-phase extraction, and three noteworthy examples of automated extractions are given. The last part of the review suggests possible near- and long-term directions of automated solid-phase extraction.