EARLY PHASE POSTMORTEM REDISTRIBUTION OF LIDOCAINE AND MIDAZOLAM IN ADULT ALBINO RATS | ||
| Egyptian Society of Clinical Toxicology Journal | ||
| Article 1, Volume 7, Issue 1, June 2019, Pages 1-23 PDF (622.87 K) | ||
| Document Type: Original Article | ||
| DOI: 10.21608/esctj.2019.62424 | ||
| Authors | ||
| Ghadeer Abdelaal* 1; Nagah Hegazy1; Ghada Elmesallamy1; Rasha Etewa2 | ||
| 1Forensic Medicine and Clinical Toxicology, Department, Faculty of Medicine, Zagazig University, Egypt | ||
| 2Medical Biochemistry Department, Faculty of Medicine, Zagazig University, Egypt | ||
| Abstract | ||
| Background: Postmortem redistribution (PMR) is the changes that occur in drug concentrations after death. Lidocaine is the most popular local anesthetic used worldwide and midazolam is a widely used pre-anesthetic anxiolytic and sedative. Aim of the Work: This work was performed to study potential early phase postmortem redistribution of lidocaine and midazolam, as well as, the influence of storage temperature on it in adult albino rats. This was done by measuring their concentrations in blood (cardiac blood and external iliac vein blood) and tissues (heart, lungs and liver). Calculation of cardiac blood to peripheral blood ratio (C/P) and Liver to peripheral blood ratio (L/P) was performed. Materials and Methods: This study was carried out on 36 adult male albino rats which divided into two main groups (18 rats each). Group I (Lidocaine): Rats received a single SC injection of 2% lidocaine HCL (67 mg/kg), and sacrificed 30 minutes later. This group was subdivided into three equal groups; AM control (L-AM), 15 minutes PM at 4ºC (L-PM4) and 15 minutes PM at 21ºC (L-PM21). Group II (Midazolam): Rats received single IV injection of midazolam (75 mg/kg), and sacrificed 30 minutes later. This group was subdivided into three equal groups; AM control (M-AM), 15 minutes PM at 4ºC (M-PM4), 15 minutes PM at 21ºC (M-PM21). Results: There were significant changes in lidocaine and midazolam concentrations in both tissues and blood samples as compared to those of corresponding AM control groups. Markers of PMR revealed early phase PMR of lidocaine by L/P ratios > 20 at 21 ºC. Storage temperature at 4ºC arrested lidocaine PMR as recorded by both C/P ratios < 1 and L/P ratios < 5. Midazolam was prone to postmortem degradation that interfered with PMR assessment. Midazolam revealed minimal early phase postmortem redistribution as demonstrated by C/P ratios just above 1 at 4 ºC. L/P ratio was a more reliable marker for PMR than C/P ratio. Conclusion: Lidocaine was highly liable to undergo early phase PMR as demonstrated by L/P ratios above 20 at 21 ºC. However, storage at 4ºC retarded lidocaine PMR. Midazolam was subjected to postmortem degradation and had minimal early phase PMR as demonstrated by C/P ratios just above 1 at 4 ºC. Recommendation: it is recommended to increase forensic toxicologists' awareness about PMR of lidocaine and midazolam, and their influence on the interpretation of PM toxicological analysis. | ||
| Keywords | ||
| PMR; Lidocaine; midazolam; storage temperature; GCMS; C/P ratio and L/P ratio | ||
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