Determination of Acyclovir in Human Plasma Samples by HPLC Method with UV Detection: Application to Single-Dose Pharmacokinetic Study.

BACKGROUND: The aim of this study is estimation of pharmacokinetic parameters: Cmax, tmax, t1/2, AUC0-t and AUC0-∞ with the two-way analysis of variance, single observation (ANOVA) for two preparations containing acyclovir. OBJECTIVE: In order to evaluate pharmacokinetic study of acyclovir, method for quantitative determination of acyclovir in human plasma should be simple, rapid and reproducible. Therefore, the method is developed, validated and applied for analysis of acyclovir in plasma samples obtained from healthy volunteers. MATERIAL AND METHODS: High performance liquid chromatographic (HPLC) method with UV-detection for the determination of acyclovir in human plasma is presented. This method involves protein precipitation with 20 % (V/V) perchloric acid. The chromatographic separation was accomplished on a reversed phase C8 column with a mobile phase composed of 0.1 % (V/V) triethylamine in water (pH 2.5). No internal standard is required. UV detection was set at 255 nm. The method was successfully applied for the evaluation of pharmacokinetic profiles of acyclovir tablets in 24 healthy volunteers. RESULTS: The validation results shows that proposed method is rugged, precise (RSDs for intra- and inter-day precision ranged from 1.02 to 8.37 %) and accurate (relative errors are less than 6.66 %). The calibration curve was linear in the concentration range of 0.1-2.0 µg/ml and the limit of quantification was 0.1 µg/ml. The Cmax, tmax and AUCs for the two products were not statistically different (p>0.05), suggesting that the plasma profiles generated by Zovirax were comparable to those produced by acyclovir manufactured by Jaka 80 company. CONCLUSION: Good precision, accuracy, simplicity, sensitivity and shorter time of analysis of the method makes it particularly useful for processing of multiple samples in a limited period of time for pharmacokinetic study of acyclovir.

Expression of matrix metalloproteinases 2, 7 and 9 in patients with colorectal cancer.

BACKGROUND/AIM: Matrix metalloproteinases (MMPs) are perceived to play a key role in tumor invasion and metastasis by their capacity to degrade basement membranes and extracellular matrix proteins. The aim of this study was to investigate the expressions of MMP-2, MMP-7 and MMP-9 in tumor tissue and their relation to clinicopathologic features in patients with colorectal cancer. METHODS: Specimens of resected colorectal cancer and surrounding normal tissue of 82 patients were immunohistochemically stained for MMP-2, MMP-7 and MMP-9. The results of immunohistochemical expression of MMPs were correlated with some clinical and pathologic parameters. RESULTS: Immunohistochemical expression of MMP-2 was more frequent in the patients with higher preoperative serum levels of carcinoembryonic antigen (CEA) (p = 0.047), MMP-2 (p = 0.018), MMP-9 (p = 0.036) and in those with lymph node metastasis (p = 0.018) and the advanced stage of the disease (p = 0.046). Expression of MMP-7 was more frequent in the patients with elevated preoperative serum levels of: CEA (p = 0.012), MMP-7 (p = 0.036), MMP-9 (p = 0.023) and with deeply invasive neoplasms (p = 0.027). MMP-9 cell expression was in a positive correlation with elevated preoperative serum levels of: CEA (p = 0.013), MMP-2 (p = 0.012), MMP-9 (p = 0.018) and depth of CRC invasion, ie T-parameter (p = 0.027). CONCLUSION: Immunohistochemical expression of MMPs is a useful indicator of the disease development and progression in patients with colorectal cancer.

Acute fulminant hepatatis in kidney transplant recipient after repeated sevoflurane anesthesia--a case report and literature review.

INTRODUCTION: A liver dysfunction induced by halogenated volatile anaesthetics is considered as a significant diagnostic problem. The aim of our report was to describe the first case of lethal hepatic failure in a female patient undergoing kidney transplantation (KTx) from a living donor after repeated sevoflurane anaesthesia. CASE PRESENTATION: A 47-year-old hypertensive and diabetic female patient received kidney from her 70-year-old mother. There was an immediate graft function and around 800 ml of blood loss on the abdominal drains, which gradually decreased after the erythrocyte and fresh frozen plasma (FFP) substitution. On the first postoperative (p.o.) day she gradually became anuric and overweighed at the next day undergoing dialysis. Because of prolonged hypotension and somnolence she required reintubation. The second day transaminases increased (AST&ALT>700, LDH>1200 U/L). On the third p.o. day she was urgently reoperated because of a sudden excessive bleeding. However, there was a rather slow flow of tears from the whole operative field that was even more excessive after the operation with signs of a consumptive coagulopathy. She was adequately substituted until the bleeding stopped more than 24 hrs after its onset. The new laboratory results showed further increase in transaminazes (3300 U/L-ALT, 5100-AST, 8900-LDH) and ultrasound investigation confirmed an extensive toxic hepatic lesion. On the fourth p.o. night the patient was stable, diuresis rate was at 100 ml/hour, but in the morning she became hyposaturated because of an increased bronchial secretion. The dialysis could not improve the cardio-respiratory insufficiency and she died 30min later. CONCLUSIONS: This case report suggests that sevoflurane can lead to a severe hepatotoxicity in at-risk individuals with repeated sevoflurane anaesthesia, having renal failure, in those with a preoperative known history of cardiovascular disorders, as well as in those with excessive extracellular volume. A particular precaution should be considered in cases of an elective surgery including organ transplantation.

Development of an HPLC method for the determination of nifedipine in human plasma by solid-phase extraction.

Nifedipine, a dihydropyridine calcium channel antagonist, is widely used in the treatment of hypertension and other cardiovascular disorders. A selective, sensitive and accurate high-performance liquid chromatographic method has been developed, validated and applied for determination of nifedipine in human plasma samples. A series of studies were conducted in order to investigate the effects of mobile phase composition, buffer concentration, mobile phase pH and concentration of organic modifiers, and to develop a convenient and easy-to-use method for quantitative analysis of nifedipine. The method involves solid-phase extraction on C18 cartridges. The chromatographic separation was accomplished on a Lichrocart Lichrospher 60 RP selectB column with a mobile phase composed of 0.020 mol/L KH2PO4 (pH 4.8) and acetonitrile (42:58, v/v). UV detection was set at 240 nm. The calibration curve was linear in the concentration range of 5.0-200.0 ng/mL for nifedipine in plasma and the limit of quantification was 5.0 ng/mL.