High Performance Liquid Chromatographic Assay for the Simultaneous Determination of Posaconazole and Vincristine in Rat Plasma

Purpose. Developing a validated HPLC-DAD method for simultaneous determination of posaconazole (PSZ) and vincristine (VCR) in rat plasma. Methods. PSZ, VCR, and itraconazole (ITZ) were extracted from 200 μL plasma using diethyl ether in the presence of 0.1 M sodium hydroxide solution. The organic layer was evaporated in vacuo and dried residue was reconstituted and injected through HC-C18 (4.6 × 250 mm, 5 μm) column. In the mobile phase, acetonitrile and 0.015 M potassium dihydrogen orthophosphate (30 : 70 to 80 : 20, linear gradient over 7 minutes) pumped at 1.5 mL/min. VCR and PSZ were measured at 220 and 262 nm, respectively. Two Sprague Dawley rats were orally dosed PSZ followed by iv dosing of VCR and serial blood sampling was performed. Results. VCR, PSZ, and ITZ were successfully separated within 11 min. Calibration curves were linear over the range of 50–5000 ng/mL for both drugs. The CV% and % error of the mean were ≤18% and limit of quantitation was 50 ng/mL for both drugs. Rat plasma concentrations of PSZ and VCR were simultaneously measured up to 72 h and their calculated pharmacokinetics parameters were comparable to the literature. Conclusion. The assay was validated as per ICH guidelines and is appropriate for pharmacokinetics drug-drug interaction studies

Editorial: Methods and application in cardiovascular and smooth muscle pharmacology: 2021

Despite significant advances in basic, translational, and clinical research tackling heart disease, cardiovascular pathologies remain among the leading causes of mortality and morbidity worldwide, being responsible for one-third of global deaths as estimated by the WHO (Organization, 2021). The complexity of risk factors and pathways underlying the development of cardiovascular disorders (CVDs) limits the efficacy of a given therapeutic intervention and necessitates combined pharmacological approaches, as well as lifestyle modification to provide a reasonable health impact (Arnett et al., 2019). Be that as it may, there remains a considerable room for scientific inquiry in pursuit of novel and more refined avenues to prevent, diagnose, mitigate, and reverse different forms of cardiovascular ailment, as well as optimize patient management. Indeed, such a need for research in this field was even further emphasized as the world faced heightened health challenges during the COVID-19 pandemic with cardiovascular complications being among the most serious consequences of SARS-CoV-2 infection (Wehbe et al., 2020)

Peri-renal adipose inflammation contributes to renal dysfunction in a non-obese prediabetic rat model: Role of anti-diabetic drugs

Diabetic nephropathy is a major health challenge with considerable economic burden and significant impact on patients’ quality of life. Despite recent advances in diabetic patient care, current clinical practice guidelines fall short of halting the progression of diabetic nephropathy to end-stage renal disease. Moreover, prior literature reported manifestations of renal dysfunction in early stages of metabolic impairment prior to the development of hyperglycemia indicating the involvement of alternative pathological mechanisms apart from those typically triggered by high blood glucose. Here, we extend our prior research work implicating localized inflammation in specific adipose depots in initiating cardiovascular dysfunction in early stages of metabolic impairment. Non-obese prediabetic rats showed elevated glomerular filtration rates and mild proteinuria in absence of hyperglycemia, hypertension, and signs of systemic inflammation. Isolated perfused kidneys from these rats showed impaired renovascular endothelial feedback in response to vasopressors and increased flow. While endothelium dependent dilation remained functional, renovascular relaxation in prediabetic rats was not mediated by nitric oxide and prostaglandins as in control tissues, but rather an upregulation of the function of epoxy eicosatrienoic acids was observed. This was coupled with signs of peri-renal adipose tissue (PRAT) inflammation and renal structural damage. A two-week treatment with non-hypoglycemic doses of metformin or pioglitazone, shown previously to ameliorate adipose inflammation, not only reversed PRAT inflammation in prediabetic rats, but also reversed the observed functional, renovascular, and structural renal abnormalities. The present results suggest that peri-renal adipose inflammation triggers renal dysfunction early in the course of metabolic disease.This study was supported by American University of Beirut Faculty of Medicine Medical Practice Plan grant #320148 granted to AFE. The funding body had no role in the design of the study or collection, analysis, and interpretation of data or in writing the manuscript

Osjetljiva spektrofotometrijska metoda za određivanje antagonista H2-receptora uz uporabu N-bromsukcinimida i p-aminofenola

A simple, accurate and sensitive spectrophotometric method for determination of H2-receptor antagonists: cimetidine (CIM), famotidine (FAM), nizatidine (NIZ), and ranitidine hydrochloride (RAN) has been full developed and validated The method was based on the reaction of these drugs with NBS and subsequent measurement of the excess N-bromosuccinimide by its reaction with p-aminophenol to give a violet colored product (max at 552 nm). Decrease in the absorption intensity (A) of the colored product, due to the presence of the drug, was correlated with its concentration in the sample solution. Different variables affecting the reaction were carefully studied and optimized. Under optimal conditions, linear relationships with good correlation coefficients (0.9988-0.9998) were found between A values and the corresponding concentrations of the drugs in a concentration range of 830, 622, 625, and 420 g mL1 for CIM, FAM, NIZ, and RAN, respectively. Limits of detection were 1.22, 1.01, 1.08, and 0.74 g mL1 for CIM, FAM, NIZ, and RAN, respectively. The method was validated in terms of accuracy, precision, ruggedness, and robustness; the results were satisfactory. The proposed method was successfully applied to the analysis of the above mentioned drugs in bulk substance and in pharmaceutical dosage forms; percent recoveries ranged from 98.5 0.9 to 102.4 0.8% without interference from the common excipients. The results obtained by the proposed method were comparable with those obtained by the official methods.Razvijena je i validirana ispravna, jednostavna i osjetljiva spektrofotometrijska metoda za određivanje antagonista H2-receptora: cimetidina (CIM), famotidina (FAM), nizatidina (NIZ) i ranitidin hidroklorida (RAN). Metoda se temelji na reakciji tih ljekovitih tvari s N-bromsukcinimidom (NBS). Višak N-bromsukcinimida određuje se nakon reakcije s p-aminofenolom s kojim daje ljubičasti produkt (max pri 552 nm). Smanjenje apsorpcijskog intenziteta (A) obojenog produkta, zbog prisutnosti ljekovite tvari korelirano je s njegovom koncentracijom u otopini uzorka. Proučavane su različite varijable koje utječu na reakciju. Linearno koncentracijsko područje za CIM, FAM, NIZ i RAN, s koeficijentom korelacije od 0,9988 do 0,9998, iznosi 830, 622, 625 odnosno 420 g mL1. Granice detekcije bile su 1,23, 1,02, 1,09 i 0,75 g mL1 za CIM, FAM, NIZ, odnosno RAN. Predložena metoda je uspješno primijenjena za analizu navedenih ljekovitih tvari i ljekovitih pripravaka. Nepreciznost od 0,7 do 1,2% i visoka ispravnost (analitički povrat između 98,5 i 102,4%), bez interferencije uobičajenih pomoćnih tvari, ukazuju na dobru analitičku metodu. Rezultati dobiveni predloženom metodom usporedivi su s rezultatima dobivenim službenom metodom

Validated stability-indicating spectrofluorimetric methods for the determination of ebastine in pharmaceutical preparations

Two sensitive, selective, economic, and validated spectrofluorimetric methods were developed for the determination of ebastine (EBS) in pharmaceutical preparations depending on reaction with its tertiary amino group. Method I involves condensation of the drug with mixed anhydrides (citric and acetic anhydrides) producing a product with intense fluorescence, which was measured at 496 nm after excitation at 388 nm

High Performance Liquid Chromatographic Assay for the Simultaneous Determination of Posaconazole and Vincristine in Rat Plasma

Purpose. Developing a validated HPLC-DAD method for simultaneous determination of posaconazole (PSZ) and vincristine (VCR) in rat plasma. Methods. PSZ, VCR, and itraconazole (ITZ) were extracted from 200 L plasma using diethyl ether in the presence of 0.1 M sodium hydroxide solution. The organic layer was evaporated in vacuo and dried residue was reconstituted and injected through HC-C18 (4.6 × 250 mm, 5 m) column. In the mobile phase, acetonitrile and 0.015 M potassium dihydrogen orthophosphate (30 : 70 to 80 : 20, linear gradient over 7 minutes) pumped at 1.5 mL/min. VCR and PSZ were measured at 220 and 262 nm, respectively. Two Sprague Dawley rats were orally dosed PSZ followed by iv dosing of VCR and serial blood sampling was performed. Results. VCR, PSZ, and ITZ were successfully separated within 11 min. Calibration curves were linear over the range of 50-5000 ng/mL for both drugs. The CV% and % error of the mean were ≤18% and limit of quantitation was 50 ng/mL for both drugs. Rat plasma concentrations of PSZ and VCR were simultaneously measured up to 72 h and their calculated pharmacokinetics parameters were comparable to the literature. Conclusion. The assay was validated as per ICH guidelines and is appropriate for pharmacokinetics drug-drug interaction studies

GPER acts through the cAMP/Epac/JNK/AP-1 pathway to induce transcription of alpha 2C adrenoceptor in human microvascular smooth muscle cells.

Raynaud's phenomenon (RP), which results from exaggerated cold-induced vasoconstriction, is more prevalent in females than males. We previously showed that estrogen increases the expression of alpha 2C-adrenoceptors (α2C-AR), the sole mediator of cold-induced vasoconstriction. This effect of estrogen is reproduced by the cell-impermeable form of the hormone (E2:BSA), suggesting a role of the membrane estrogen receptor, GPER, in E2-induced α2C-AR expression. We also previously reported that E2 upregulates α2C-AR in microvascular smooth muscle cells (VSMCs) via the cAMP/Epac/Rap/JNK/AP-1 pathway, and that E2:BSA elevates cAMP levels. We, therefore, hypothesized that E2 employs GPER to upregulate α2C-AR through the cAMP/Epac/JNK/AP-1 pathway. Our results show that G15, a selective GPER antagonist, attenuates the E2-induced increase in α2C-AR transcription. G-1, a selective GPER agonist, induced α2C-AR transcription, which was concomitant with elevated cAMP levels and JNK activation. Pretreatment with ESI09, an Epac inhibitor, abolished both G-1-induced α2C-AR upregulation and JNK activation. Moreover, pretreatment with SP600125, a JNK specific inhibitor, but not H89, a PKA specific inhibitor, abolished G-1-induced α2C-AR upregulation. In addition, transient transfection of an Epac dominant negative mutant (Epac-DN) attenuated G-1-induced activation of α2C-AR promoter. This inhibitory effect of Epac-DN on α2C-AR promoter was overridden by the co-transfection of constitutively active JNK mutant. Furthermore, mutation of AP-1 site in the α2C-AR promoter abrogated G1-induced expression. Collectively, these results indicate that GPER upregulates α2C-AR through the cAMP/EPAC/ JNK/AP-1 pathway. These findings unravel GPER as a new mediator of cold-induced vasoconstriction, and present it as a potential target for treating RP in estrogen-replete females. [Abstract copyright: Copyright © 2023 Wolters Kluwer Health, Inc. All rights reserved.

Validated spectrophotometric methods for the evaluation of Oseltamivir counterfeit pharmaceutical capsules

Four rapid, reliable and economical spectrophotometric methods have been established for the quantitative determination of Oseltamivir phosphate (OST) without the interference of ascorbic acid (ASC) found in some of its counterfeit capsules. The first method involves the use of derivative spectrophotometry with the zero-crossing technique where OST was easily determined using its 1D (Δλ = 3) at 219 nm. The second method is based on a first-order derivative ratio spectrophotometry (1DD, Δλ = 5) where 218 nm was selected for its quantification, while the third method applies a more advanced spectrophotometric method based on the ratio difference spectrophotometry (RD) in which the difference in absorbance ratio was measured between 217 and 210 nm. In the fourth method, difference spectrophotometric method (ΔA) is applied by subtracting absorbance at 252 from that at 263 nm where the difference in absorbance was zero for ASC. The proposed methods were validated for linearity, accuracy, precision and selectivity. Synthetic mixtures of different proportions and commercial capsules were assayed by the proposed methods and the results revealed good accuracy and repeatability of the developed methods