Amlodipine Besylate: Properties, Uses & FAQs

Amlodipine besylate is a second-generation dihydropyridine calcium channel blocker widely used as a research reagent to investigate L-type calcium channel pharmacology, vascular smooth muscle physiology, and cardiovascular drug mechanisms in vitro and in vivo.

Chemical Name

3-Ethyl 5-methyl 2-(2-aminoethoxymethyl)-4-(2-chlorophenyl)-6-methyl-1,4-dihydropyridine-3,5-dicarboxylate benzenesulfonate

Molecular Formula

C₂₀H₂₅ClN₂O₅ · C₆H₆O₃S

Molecular Weight

567.05 g/mol

CAS Number

111470-99-6

Mechanism of Action

Selective blocker of L-type voltage-gated calcium channels (Cav1.x); reduces Ca²⁺ influx in vascular smooth muscle and cardiac cells

Purity (typical)

≥98% (HPLC)

Appearance

White to off-white crystalline powder

SKU

A128786

What Is Amlodipine Besylate and Why Is It Used in Research?

Amlodipine besylate is the besylate (benzenesulfonate) salt form of amlodipine, a third-generation long-acting dihydropyridine (DHP) calcium channel antagonist. The besylate salt is preferred over earlier salt forms because of its superior chemical stability, improved aqueous solubility, and non-hygroscopic crystalline character, making it well-suited for preparation of stock solutions in research settings.

In preclinical research, amlodipine besylate serves as a pharmacological tool compound to selectively inhibit L-type (Cav1.2, Cav1.3) voltage-gated calcium channels. This selectivity makes it valuable for dissecting the role of calcium influx in vascular smooth muscle contraction, cardiomyocyte excitation–contraction coupling, and endothelial function. Researchers also employ it in models of hypertension, atherosclerosis, cardiac hypertrophy, and ischemia–reperfusion injury.

Solubility and Preparation of Stock Solutions

Amlodipine besylate is sparingly soluble in water at neutral pH (approximately 1–5 mg/mL depending on temperature and buffer conditions). It demonstrates significantly better solubility in polar organic solvents. Recommended solvents for stock solution preparation include:

• DMSO: ≥10 mg/mL (commonly used; introduce ≤0.1% v/v into aqueous assay systems to minimise solvent effects)
• Ethanol: soluble; suitable for applications sensitive to DMSO
• PBS or physiological saline: limited solubility; sonication and gentle warming (37 °C) may aid dissolution for in vivo dosing vehicles

It is recommended to prepare fresh working solutions by diluting concentrated DMSO stocks into aqueous buffer immediately before use, and to verify absence of precipitation via visual inspection or dynamic light scattering when working at concentrations above 10 µM in aqueous media.

Storage, Stability and Handling

Amlodipine besylate is light-sensitive owing to its dihydropyridine core, which undergoes photochemical oxidation to the corresponding pyridine analogue upon prolonged exposure to UV or visible light. Proper storage and handling practices include:

• Store as a solid at 2–8 °C (or −20 °C for long-term archival) in tightly sealed, amber or foil-wrapped vials.
• Protect all solutions from light; conduct experiments under subdued or amber-filtered lighting where practical.
• DMSO stock solutions stored at −20 °C in aliquots are stable for at least 6 months when protected from light and freeze–thaw cycles are minimised.
• Allow cold vials to equilibrate to room temperature before opening to prevent moisture condensation on the powder.

Standard laboratory PPE (gloves, eye protection, lab coat) should be worn when handling the compound. Refer to the Safety Data Sheet (SDS) for full hazard information.

Common Experimental Applications

Amlodipine besylate is employed across a range of in vitro and in vivo experimental paradigms:

• Vascular pharmacology: concentration–response studies in isolated aortic rings or mesenteric artery preparations to characterise L-type calcium channel blockade and vasodilation.
• Cell-based assays: inhibition of KCl- or Bay K 8644-stimulated calcium entry in smooth muscle cells, HEK293 cells stably expressing Cav1.2, or cardiomyocytes; quantified by Fura-2 AM or Fluo-4 fluorescence imaging.
• Rodent hypertension models: oral or intraperitoneal administration in spontaneously hypertensive rats (SHR) or Ang II–infusion models to evaluate antihypertensive efficacy and end-organ protection.
• Cardiac hypertrophy and fibrosis: chronic dosing studies to assess attenuation of maladaptive remodelling via reduction of intracellular Ca²⁺ overload.
• Combination pharmacology: used alongside renin–angiotensin system inhibitors or statins to probe synergistic cardiovascular protection mechanisms.

Purity, Quality and Regulatory Considerations

Aladdin Scientific's amlodipine besylate (SKU A128786) is supplied at ≥98% purity as determined by HPLC. A certificate of analysis (CoA) confirming lot-specific purity, identity (e.g., NMR or MS), and appearance is available on request or via the product page.

This product is intended for research use only (RUO) and is not manufactured under GMP conditions. It is therefore not suitable for use in human clinical trials, veterinary therapeutic applications, or as an active pharmaceutical ingredient (API) without additional qualification. Researchers requiring GMP-grade material for IND-enabling studies should contact Aladdin Scientific for custom sourcing options.

For regulatory submissions, researchers should retain the CoA, SDS, and any relevant spectral data as part of their experimental documentation. Export of this compound may be subject to local regulations; purchasers are responsible for compliance with applicable laws.

Frequently asked questions

What is the recommended concentration range for amlodipine besylate in cell-based calcium channel assays?

Amlodipine besylate typically exhibits IC₅₀ values in the low nanomolar range (1–10 nM) against L-type calcium channels in electrophysiological and fluorescence-based assays, with full inhibition often achieved at 100–1000 nM. For concentration–response experiments, a range of 0.1 nM to 10 µM spanning at least 4 log units is recommended to define the complete sigmoidal curve. Always confirm solubility at the top concentration used in aqueous assay buffer.

How should I handle the light sensitivity of amlodipine besylate during experiments?

Because the dihydropyridine ring system undergoes photodegradation to a pyridine by-product under UV and visible light, all stock solutions and working dilutions should be prepared and stored in amber vials or tubes wrapped in aluminium foil. Plate-reader assays and microscopy experiments should minimise unnecessary light exposure; amber or red lighting in the working area is advisable. Degradation can be monitored by HPLC if solution stability over extended experimental periods is a concern.

Can amlodipine besylate be used in animal studies, and what are common dosing routes?

Yes, amlodipine besylate is widely used in rodent cardiovascular models. Common administration routes include oral gavage (typically dissolved or suspended in 0.5% methylcellulose or 0.9% saline vehicle) and intraperitoneal injection (in DMSO/saline mixtures). Doses in published murine studies generally range from 2–10 mg/kg/day, though optimal doses should be established based on specific model requirements. Researchers should consult relevant literature and institutional IACUC guidelines when designing in vivo studies.

Is amlodipine besylate selective for L-type channels over other calcium channel subtypes?

Amlodipine besylate shows high selectivity for L-type (Cav1.x) voltage-gated calcium channels over T-type (Cav3.x), N-type (Cav2.2), and P/Q-type (Cav2.1) channels at pharmacologically relevant concentrations. This selectivity is the basis for its primary use in cardiovascular research. However, at very high concentrations (typically >10 µM) off-target effects on other ion channels may emerge, so experimental concentrations should be kept within the validated pharmacological range.

What solvent is best for preparing amlodipine besylate stock solutions for in vitro assays?

DMSO is the most commonly used solvent for preparing concentrated stock solutions (≥10 mg/mL) due to amlodipine besylate's good solubility and DMSO's compatibility with most cell-based systems at low final concentrations (≤0.1% v/v). Ethanol is an alternative for DMSO-sensitive assays. Aqueous solubility is limited, so direct dissolution in PBS or cell culture medium alone is not recommended for concentrations above approximately 1 mg/mL without the aid of co-solvents or cyclodextrin complexation.

References

1. Burges RA, Moisey D, Gardiner DG. Calcium antagonist properties of amlodipine in isolated tissues. J Cardiovasc Pharmacol. 1987.
2. Nayler WG. Amlodipine. Berlin: Springer-Verlag; 1993. (General reference for pharmacological profile of amlodipine)
3. Triggle DJ. Calcium channel antagonists: clinical uses — past, present and future. Biochem Pharmacol. 2007.
4. Aladdin Scientific Certificate of Analysis, Amlodipine besylate, SKU A128786. (Lot-specific; available on request)

Products are supplied for research and development use only. Not for use in humans, animals, diagnosis, or therapy.