Pharmacokinetic drug interactions between digoxin and antiarrhythmic agents and calcium channel blocking agents: an appraisal of study methodology

UPLC Technique in Pharmacy—An Important Tool of the Modern Analyst

In recent years, ultra-efficient liquid chromatography (UPLC) has gained particular popularity due to the possibility of faster separation of small molecules. This technique, used to separate the ingredients present in multi-component mixtures, has found application in many fields, such as chemistry, pharmacy, food, and biochemistry. It is an important tool in both research and production. UPLC created new possibilities for analytical separation without reducing the quality of the obtained results. This technique is therefore a milestone in liquid chromatography. Thanks to the increased resolution, new analytical procedures, in many cases, based on existing methods, are being developed, eliminating the need for re-analysis. Researchers are trying to modify and transfer the analytical conditions from the commonly used HPLC method to UPLC. This topic may be of strategic importance in the analysis of medicinal substances. The information contained in this manuscript indicates the importance of the UPLC technique in drug analysis. The information gathered highlights the importance of selecting the appropriate drug control tools. We focused on drugs commonly used in medicine that belong to various pharmacological groups. Rational prescribing based on clinical pharmacology is essential if the right drug is to be administered to the right patient at the right time. The presented data is to assist the analyst in the field of broadly understood quality control, which is very important, especially for human health and treatment. This manuscript shows that the UPLC technique is now an increasingly used tool for assessing the quality of drugs and determining the identity and content of active substances. It also allows the monitoring of active substances and finished products during their processing and storage.

A review of eprosartan pharmacokinetic and pharmacodynamic drug interaction studies

A series of clinical pharmacology studies was conducted to characterize potential interactions between eprosartan and other commonly prescribed drugs. Separate studies assessed the effect of eprosartan on the pharmacokinetics of digoxin and hydrochlorothiazide (HCTZ) and the pharmacodynamics of warfarin and glyburide (glibenclamide), as well as the effects of ranitidine, HCTZ, fluconazole, and ketoconazole on eprosartan pharmacokinetics. Eprosartan had no significant effect on the pharmacokinetics of digoxin and HCTZ and the pharmacodynamics of warfarin and glyburide. Thus, no dosing adjustments are necessary during concomitant therapy with these agents. Ranitidine, HCTZ, ketoconazole, and fluconazole had no effect on eprosartan pharmacokinetics. Single or multiple oral doses of eprosartan were safe and well tolerated when coadministered with these agents.

Captopril does not interact with the pharmacodynamics and pharmacokinetics of digitoxin in healthy man

The chronic oral administration of 0.07 mg digitoxin o.d. for up to 58 days to 12 healthy volunteers caused a small drop in mean heart rate HR (95% CI: -7.9 to -1.6 beats.min-1), in mean diastolic blood pressure (95% CI: -8.3 to -0.4 mmHg), shortening of the QTc-interval (95% CI: -42 to -19 ms), shortening of the HR-corrected pre-ejection period PEPc (95% CI: -16 to -1 ms) and electromechanical systole QS2c (95% CI: -25 to -1 ms), and an increase in the impedance cardiographic Heather index (dZ/dtmax/RZ, 95% CI: 0.3 to 4.3) relative to the baseline measurements before digitalisation. The concomitant administration of 25 mg oral captopril b.d. did not significantly alter these responses relative to the concomitant double-blind administration of placebo, nor did it alter the pharmacokinetic characteristics of plasma digitoxin at steady state. Thus, no relevant change in the pharmacokinetic and pharmacodynamic characteristics of chronically administered digitoxin were induced by concomitant treatment with captopril.

Pharmacokinetic interactions with digoxin

Numerous pharmacological agents have been shown to produce clinically significant pharmacokinetic interactions with digoxin. Drugs which reduce digoxin absorption include the antacids aluminium hydroxide, magnesium hydroxide and magnesium trisilicate, the antidiarrhoeals kaolin and pectin, the hypocholesterolaemic agent cholestyramine and the chemotoxins cyclophosphamide, vincristine and bleomycin. Certain antibiotics including sulphasalazine, neomycin and aminosalicylic acid reduce digoxin absorption while others, including erythromycin and tetracycline, increase the bioavailability of digoxin in some patients. Capsule preparations of digoxin in solution are less subject to several of the interactions which affect the absorption and bioavailability of digoxin tablets. Various drugs induce alterations in the volume of distribution and clearance of digoxin. Cardiac patients receiving digoxin therapy are particularly prone to interactions with commonly co-administered medications such as the antiarrhythmics quinidine and amiodarone, the calcium channel blockers verapamil and nifedipine, and possibly some vasodilating agents. Studies of digoxin interactions have yielded discrepant results, indicating the need for careful analysis of investigational design before arriving at clinical conclusions.