Salicylaldehyde isonicotinoyl hydrazone (SIH) is an intracellular iron chelator with well documented potential to protect against oxidative injury both in vitro and in vivo. However, it suffers from short biological half-life caused by fast hydrolysis of the hydrazone bond. Recently, a concept of boronate prochelators has been introduced as a strategy that might overcome these limitations. This study presents two complementary analytical methods for detecting the prochelator-boronyl salicylaldehyde isonicotinoyl hydrazone-BSIH along with its active metal-binding chelator SIH in different solution matrices and concentration ranges. An LC-UV method for determination of BSIH and SIH in buffer and cell culture medium was validated over concentrations of 7-115 and 4-115 μM, respectively, and applied to BSIH activation experiments in vitro. An LC-MS assay was validated for quantification of BSIH and SIH in plasma over the concentration range of 0.06-23 and 0.24-23 μM, respectively, and applied to stability studies in plasma in vitro as well as analysis of plasma taken after i.v. administration of BSIH to rats. A Zorbax-RP bonus column and mobile phases containing either phosphate buffer with EDTA or ammonium formate and methanol/acetonitrile mixture provided suitable conditions for the LC-UV and LC-MS analysis, respectively. Samples were diluted or precipitated with methanol prior to analysis. These separative analytical techniques establish the first validated protocols to investigate BSIH activation by hydrogen peroxide in multiple matrices, directly compare the stabilities of the prochelator and its chelator in plasma, and provide the first basic pharmacokinetic data of this prochelator. Experiments reveal that BSIH is stable in all media tested and is partially converted to SIH by H2O2. The observed integrity of BSIH in plasma samples from the in vivo study suggests that the concept of prochelation might be a promising strategy for further development of aroylhydrazone cytoprotective agents.

• Keywords
• Aroylhydrazone, Boronyl salicylaldehyde isonicotinoyl hydrazone, Pharmacokinetics, Prochelator salicylaldehyde isonicotinoyl hydrazone, Stability,
• MeSH
• Aldehydes analysis   blood   MeSH
• Chelating Agents analysis   MeSH
• Chromatography, Liquid methods   MeSH
• Mass Spectrometry methods   MeSH
• Hydrazones analysis   blood   MeSH
• Culture Media chemistry   MeSH
• Boronic Acids analysis   blood   MeSH
• Isonicotinic Acids analysis   blood   MeSH
• Molecular Structure MeSH
• Rats, Wistar MeSH
• Reference Standards MeSH
• Sensitivity and Specificity MeSH
• Spectrophotometry, Ultraviolet methods   MeSH
• Drug Stability MeSH
• Animals MeSH
• Check Tag
• Male MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Research Support, N.I.H., Extramural MeSH
• Names of Substances
• (isonicotinic acid (2-(4,4,5,5-tetramethyl-(1,3,2)dioxaborolan-2-yl)benzylidene)hydrazide) MeSH Browser
• Aldehydes MeSH
• Chelating Agents MeSH
• Hydrazones MeSH
• Culture Media MeSH
• Boronic Acids MeSH
• Isonicotinic Acids MeSH
• salicylaldehyde isonicotinoyl hydrazone MeSH Browser

BACKGROUND AND PURPOSE: The clinical utility of anthracycline antineoplastic drugs is limited by the risk of cardiotoxicity, which has been traditionally attributed to iron-mediated production of reactive oxygen species (ROS). EXPERIMENTAL APPROACH: The aims of this study were to examine the strongly lipophilic iron chelator, salicylaldehyde isonicotinoyl hydrazone (SIH), for its ability to protect rat isolated cardiomyocytes against the toxicity of daunorubicin (DAU) and to investigate the effects of SIH on DAU-induced inhibition of proliferation in a leukaemic cell line. Cell toxicity was measured by release of lactate dehydrogenase and staining with Hoechst 33342 or propidium iodide and lipid peroxidation by malonaldehyde formation. KEY RESULTS: SIH fully protected cardiomyocytes against model oxidative injury induced by hydrogen peroxide exposure. SIH also significantly but only partially and with no apparent dose-dependency, reduced DAU-induced cardiomyocyte death. However, the observed protection was not accompanied by decreased lipid peroxidation. In the HL-60 acute promyelocytic leukaemia cell line, SIH did not blunt the antiproliferative efficacy of DAU. Instead, at concentrations that reduced DAU toxicity to cardiomyocytes, SIH enhanced the tumoricidal action of DAU. CONCLUSIONS AND IMPLICATIONS: This study demonstrates that iron is most likely involved in anthracycline cardiotoxicity and that iron chelation has protective potential, but apparently through mechanism(s) other than by inhibition of ROS-induced injury. In addition to cardioprotection, iron chelation may have considerable potential to improve the therapeutic action of anthracyclines by enhancing their anticancer efficiency and this potential warrants further investigation.

• MeSH
• Leukemia, Promyelocytic, Acute metabolism   pathology   MeSH
• Aldehydes pharmacology   MeSH
• Time Factors MeSH
• Iron Chelating Agents pharmacology   MeSH
• Cytoprotection MeSH
• Daunorubicin toxicity   MeSH
• HL-60 Cells MeSH
• Hydrazones pharmacology   MeSH
• Myocytes, Cardiac drug effects   metabolism   pathology   MeSH
• Rats MeSH
• Humans MeSH
• Malondialdehyde metabolism   MeSH
• Animals, Newborn MeSH
• Oxidative Stress drug effects   MeSH
• Lipid Peroxidation drug effects   MeSH
• Rats, Wistar MeSH
• Cell Proliferation drug effects   MeSH
• Antibiotics, Antineoplastic toxicity   MeSH
• Cell Survival drug effects   MeSH
• Dose-Response Relationship, Drug MeSH
• Animals MeSH
• Check Tag
• Rats MeSH
• Humans MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Aldehydes MeSH
• Iron Chelating Agents MeSH
• Daunorubicin MeSH
• Hydrazones MeSH
• Malondialdehyde MeSH
• Antibiotics, Antineoplastic MeSH
• salicylaldehyde isonicotinoyl hydrazone MeSH Browser