Amlodipine besylate/olmesartan medoximil fixed combination for the treatment of hypertension

Triple combination therapy to improve blood pressure control: experience with olmesartan-amlodipine-hydrochlorothiazide therapy

INTRODUCTION

Effective treatment of hypertension is a key strategy for preventing and reducing the burden of hypertension-related cardiovascular diseases. In spite of these well-established concepts, hypertension remains poorly controlled, worldwide. Among the different pharmacological strategies required to improve blood pressure (BP) control, a more extensive use of combination therapy is progressively emerging as a cornerstone of a more effective treatment of hypertension. Among different drug combinations currently available for the clinical management of hypertension, those based on the association of drugs inhibiting the renin-angiotensin system, thiazide diuretics and calcium channel blockers have demonstrated to be very effective in lowering both systolic and diastolic, clinic and 24-h ambulatory BP levels with a good tolerability and safety profile.

AREAS COVERED

In the present manuscript the authors provide an overview of the evidence supporting the use of triple combination therapy with different classes of antihypertensive drugs, with a particular focus on those based on olmesartan medoxomil, a thiazide diuretic (hydrochlorothiazide) and a calcium channel blocker (amlodipine besylate).

EXPERT OPINION

Available data indicate that triple combination therapy based on olmesartan provides effective and sustained clinical and 24-h BP control in a high proportion of individuals among a broad range of hypertensive patients.

Development of a novel 96-microwell assay with high throughput for determination of olmesartan medoxomil in its tablets

A novel 96-microwell-based spectrophotometric assay has been developed and validated for determination of olmesartan medoxomil (OLM) in tablets. The formation of a colored charge-transfer (CT) complex between OLM as a n-electron donor and 2, 5-dichloro-3, 6-dihydroxy-1, 4-benzoquinone (p-chloranilic acid, pCA) as a π-electron acceptor was investigated, for the first time, and employed as a basis in the development of the proposed assay. The proposed assay was carried out in 96-microwell plates. The absorbance of the colored-CT complex was measured at 490 nm by microwell-plate absorbance reader. The optimum conditions of the reaction and the analytical procedures of the assay were established. Under the optimum conditions, linear relationship with good correlation coefficient was found between the absorbance and the concentration of OLM in the range of 1-200 μg ml-1. The limits of detection and quantitation were 0.3 and 1 μg ml-1, respectively. No interference was observed from the additives that are present in the pharmaceutical formulation or from hydrochlorothiazide and amlodipine that are co-formulated with OLM in some formulations. The assay was successfully applied to the analysis of OLM in tablets with good accuracy and precision. The assay described herein has great practical value in the routine analysis of OLM in quality control laboratories, as it has high throughput property, consumes minimum volume of organic solvent thus it offers the reduction in the exposures of the analysts to the toxic effects of organic solvents, and reduction in the analysis cost by 50-fold. Although the proposed assay was validated for OLM, however, the same methodology could be used for any electron-donating analyte for which a CT reaction can be performed.

Role of olmesartan in combination therapy in blood pressure control and vascular function

Angiotensin receptor blockers have emerged as a first-line therapy in the management of hypertension and hypertension-related comorbidities. Since national and international guidelines have stressed the need to control blood pressure to <140/90 mmHg in uncomplicated hypertension and <130/80 mmHg in those with associated comorbidities such as diabetes or chronic kidney disease, these goal blood pressures can only be achieved through combination therapy. Of several drugs that can be effectively combined to attain the recommended blood pressure goals, fixed-dose combinations of angiotensin receptor blockers and the calcium channel blocker amlodipine provide additive antihypertensive effects associated with a safe profile and increased adherence to therapy. In this article, we review the evidence regarding the beneficial effects of renin–angiotensin system blockade with olmesartan medoxomil and amlodipine in terms of blood pressure control and improvement of vascular function and target organ damage.