Progress of Amlodipine and Enalapril in the Treatment of

Hypertension

Yifan Wang

College of Pharmaceutical Sciences, Zhejiang Chinese Medical University, Hangzhou, China

Keywords: Hypertension, Amlodipine, Enalapril, Pharmacology, Origin, Delivery, Pharmacoeconomic.

Abstract: BACKGROUND: Hypertension is a long-term chronic disease that has a tremendous negative impact on

people's lives, and its prevalence varies by gender, region, and ethnicity. Calcium channel blockers (CCBs)

and angiotensin-converting enzyme inhibitors (ACEIs) are widely used among the first-line antihypertensive

agents. CONTENT: The type, epidemiology, pathology, and therapeutic means of hypertension were

analysed. The origin of amlodipine, a representative drug of CCBs, and enalapril, a representative drug of

ACEIs for the treatment of hypertension was analysed, and their latest progress in pharmacological effects,

delivery, combined use, and pharmacoeconomics were summarized and compared. RESULTS: Amlodipine

is more suitable for patients who need myocardial protection, and enalapril is more suitable for patients with

ventricular hypertrophy. The combination of the two drugs provides better protection for the cardiovascular

system. Both drugs are primarily administered orally, but different effects can be achieved by using different

dosage forms. Amlodipine is more affordable than enalapril and has a larger market.

1 INTRODUCTION

Heart and cardiovascular and cerebrovascular

diseases are the number one cause of death for people

in developed countries and 44% of people in China

died because of heart and cardiovascular and

cerebrovascular diseases (Bai, et al. 2018). Therefore,

research on the cardiovascular system has become the

focus of attention of scientists in the fields of

medicine and pharmacy from all over the world.

Among them, hypertension, as an important factor in

increasing the risk of cardiovascular disease has

attracted much attention.

This article analyzed s the typology,

epidemiology, pathology, and treatment of

hypertension in the first place. Hypertension, also

known as systemic arterial hypertension, is

manifested by a long-term increase in systemic

arterial blood pressure. Blood pressure is usually

expressed as the ratio of the systolic pressure (that is,

the pressure of the arterial wall when the heart is

contracting) to the diastolic pressure (the pressure

when the heart is in diastole) (Oparil, et al. 2018). As

shown in Table 1, hypertension can be divided into

the following stages. Hypertension is a long-term

chronic disease that has a great negative impact on

people's lives. And because hypertension is difficult

to cure, the vast majority of hypertensive patients

need long-term medication or even lifelong

medication (Tsioufis, and Thomopoulos 2017).

Hypertension is still an unsolved medical problem,

and therefore hypertension research still needs to be

carried out in depth. The analyzation of hypertension

in this paper provides some material to support and

enlighten the subsequent related studies.

Table 1: Categories of BP in Adults

Blood

Pressure

Category

Systolic blood

pressure (SBP)

Diastolic blood

pressure (DBP)

Normal <120mmHg and <80mmHg

Elevated 120~129mmHg and <80mmHg

Hypertension

Stage 1 130~139mmHg or 80~89mmHg

Stage 2 ≥140mmHg or ≥90mmHg

The article analysed the origins of amlodipine, a

representative drug of the CCB class for the treatment

of hypertension, and enalapril, a representative drug of

the ACEI class, to sort out the history of drug

development and make it clearer and more definite.

The pharmacological effects, routes of administration,

co-administration, and the latest progress of

pharmacoeconomics of the two drugs are also

206

Wang, Y.

Progress of Amlodipine and Enalapril in the Treatment of Hypertension.

DOI: 10.5220/0011244300003438

In Proceedings of the 1st International Conference on Health Big Data and Intelligent Healthcare (ICHIH 2022), pages 206-214

ISBN: 978-989-758-596-8

summarized and compared. It provides a

comprehensive reference for the selection and

comparison of drugs for the treatment of hypertension,

and lays the foundation for the in-depth study of the

pharmacological effects and targets of action of these

two drugs.

2 HYPERTENSION

2.1 Types of the Hypertension

The cause of the vast majority of hypertension is

unknown, called essential hypertension(EH); a small

amount of hypertension has a cause that can be

checked, called secondary hypertension(SH).

The etiology and mechanism of essential

hypertension are still unclear, but with the continuous

deepening of research, some people believe that

essential hypertension is not a disease but a

syndrome. A major manifestation of this syndrome is

increased blood pressure (Manosroi, and Williams

2019). The emergence of essential hypertension is not

caused by a single factor. It is more caused by the

cumulative effect of multiple factors. Studies have

supported this view, such as genetic inheritance and

long-term high-salt diet. Habits, the influence of the

microbiota in the body on blood pressure

(Chakraborty, et al. 2020).

Common causes of secondary hypertension

include obstructive sleep apnea (OSA), renal

parenchymal disease, renal artery stenosis, and

primary hyperaldosteronism (PA) (Rimoldi, Scherrer,

and

Messerli

2014). It is worth mentioning that many

patients with secondary hypertension still have

hypertension symptoms after removing the secondary

causes. This indicates that many patients with

secondary hypertension may be accompanied by

essential hypertension or irreversible remodeling of

blood vessels.

2.2 Epidemiology of the Hypertension

In China, the symptoms of hypertension are SBP 

140mmHg and DBP  90mmHg. According to the

report paper, the prevalence of hypertension in China

is increasing, and it is characterized by 1)higher rates

of hypertension in men than in women, 2)higher

prevalence in the north than in the south, 3)higher

prevalence in rural areas than in urban areas, 4)and

differences in prevalence between ethnic groups (J

Geriatr Cardiol 2019). As of 2015, the awareness rate

of patients with hypertension was only 55.7%, the

treatment rate was less than 50%, and only 20% of the

patients treated had their blood pressure under control

(Wei, et al. 2021).

Globally, about 31.1% of adults suffer from

hypertension, and the incidence in developed

countries is higher than that in developing countries.

There is an age difference in hypertension, that is, as

the age increases, the incidence increases, as shown

in Table 2.

Table 2: Age-specific and age-standardized prevalence estimates and absolute numbers of men and women with hypertension

in high-income and low- and middle-income countries in 2010 (Mills, et al., 2016)

High blood pressure is often not a fatal factor, but

high blood pressure can cause organ damage, increase

the risk of other cardiovascular diseases, and may

have complications. Some complications of

hypertension include renal failure, stroke, heart

failure, coronary heart disease, etc., and most of these

complications can cause death and disability (Flack,

et al. 2003).

Progress of Amlodipine and Enalapril in the Treatment of Hypertension

207

2.3 Pathology of the Hypertension

The basic factors that form arterial blood pressure are

cardiac output and peripheral vascular resistance. The

former is affected by heart function, return blood

volume, and blood volume and the latter is mainly

affected by the tension of the arterioles. The

sympathetic nervous system and the renin-

angiotensin system (RAS) regulate the above two

factors to control blood pressure within a certain

range.

2.4 Treatment of the Hypertension

At present, the treatment of hypertension advocates

comprehensive treatment, that is, non-drug treatment

and drugs are combined to control the patient's blood

pressure.

Non-drug treatment is the change in the patient’s

living habits to control risk factors. This method

advocate reducing sodium and salt intake, reasonable

dietary arrangements, regular exercise, quitting

smoking and drinking, and maintaining a good mood

(J Geriatr Cardiol 2019).

In terms of drug treatment, currently, diuretics,

calcium channel blockers, β receptor blockers,

angiotensin converting enzyme inhibitors (ACEI),

receptor blockers, which are widely used or

called first-line antihypertensive drugs, are widely

used medicine. Clinical treatment of hypertension

often adopts combination medications to reduce the

damage to the patient's target organs and reduce

complications (Tsioufis, and Thomopoulos 2017).

3 DESCRIPTION OF CHEMICAL

STRUCTURES OF DRUGS

3.1 Structure and Nomenclature

3.1.1 Structure and Nomenclature of

amlodipine

2D Structure: 3D Structure:

Figure 1: 2D and 3D structures of amlodipine.

The figure 1 shows the 2D and 3D structures of

amlodipine. The amlodipine contains a benzene ring

and a dihydropyridine ring, from the 3D structure can

be seen that the two rings are not co-plane, but in a

state perpendicular to each other. Dihydropyridine

ring 3, 5-bit replacement group is different, so C4 is

the stereoscopic center, and the activity of S

configuration is stronger than R configuration

(Coelho, et al. 2021).

Nomenclature:

The IUPAC Name of amlodipine is 3-O-ethyl 5-

O-methyl 2-(2-aminoethoxymethyl)-4-(2-

chlorophenyl)-6-methyl-1,4-dihydropyridine-3,5-

dicarboxylate. This drug has many brand names in the

market, such as Amlobenz, Azor, Caduet, Consensi,

Dafiro, Exforge, Exforge Hct, Katerzia, Lotrel,

Norvasc, Prestalia, Tribenzor, Twynsta, Viacoram.

Clinical drugs amlodipine maleate and amlodipine

besylate are widely used.

3.1.2 Structure and Nomenclature of

enalapril

2D structure: 3D Structure:

Figure 2: 2D and 3D structures of enalapril

The figure 2 shows the 2D and 3D structures of

enalapril. The structure of enalapril contains a

benzene ring, tetrahydropyrrole ring, carboxyl group,

carbonyl group, an ester bond, and other structures.

There are two chiral carbon atoms in the structure.

Nomenclature:

The IUPAC Name of enalapril is (2S)-1-[(2S)-2-

[[(2S)-1-ethoxy-1-oxo-4-phenylbutan-2-

yl]amino]propanoyl]pyrrolidine-2-carboxylic acid.

This drug has three brand names on market, Epaned,

Vaseretic, and Vasotec.

3.2 Chemical and Physical Properties

3.2.1

Chemical and Physical Properties

of amlodipine

The molecular formula is C

ClN

, this drug is

a small molecule drug. Its molecular weight is 408.9,

solid, slightly soluble in water. The 𝑝𝐾



ICHIH 2022 - International Conference on Health Big Data and Intelligent Healthcare

208

amlodipine is 9.4(amine)

3.2.2 Chemical and Physical Properties

of enalapril

The molecular formula of enalapril is C

this drug is a small molecule drug. Its molecular

weight is 376.4, solid, Its solubility in water is

1.64 × 10



mg/L at 25 °C. The pKa of enalapril

p𝐾



1 = 3.0 (carboxylic acid) and p𝐾



2 =

5.5 (secondary amide).

4 DISCUSSION OF DRUG

PHARMACOLOGY

4.1 Origin and History of Drugs

4.1.1 Origin and history of Amlodipine

The study of calcium channel blockers on the

cardiovascular system began around the 1960s.

Amlodipine is the third generation dihydropyridine

calcium channel blocker, which is modified from the

first marketed dihydropyridine CCB nifedipine.

Nifedipine was launched in 1975 and has been

effective in controlling hypertension since it was

launched. Compared with nifedipine, amlodipine has

a long-lasting and stable lowering of blood pressure.

It has become a once-a-day antihypertensive drug,

which greatly improves the compliance of

hypertensive patients (Burges, and Moisey 1994).

Amlodipine can also reverse left ventricular

hypertrophy (Lu, et al. 2016), especially for patients

with hypertension and left ventricular hypertrophy.

4.1.2 Origin and History of Enalapril

In 1971, teprotide, the first active substance with an

inhibitory effect on angiotensin converting enzyme,

was isolated from the venom of a Brazilian snake.

However, the oral administration of teprotide was

ineffective, so it was necessary to find a more stable

structure. Inspired by the inhibitor of

carboxypeptidase A (an exopeptidase containing zinc

ion active center, which was thought to be similar to

ACE at that time) (Cushman, et al. 1982),

succinylproline was synthesized. The product had a

certain inhibitory effect on ACE, but its activity was

low. To further increase the inhibitory activity,

succinylproline was structurally modified by adding

chiral carbon and replacing carboxyl with sulfhydryl.

Surprisingly, this structural transformation increased

the inhibitory effect by 2000 times (Cushman, and

Ondetti 1991). This is the first ACEI drug captopril,

which was listed by Squibb in 1981.

But then captopril was reported to have serious

adverse reactions, such as proteinuria and taste loss.

These adverse reactions were related to the sulfhydryl

group contained in its structure (Jaffe 1986).

Therefore, to eliminate these adverse reactions, the

structure of captopril was modified α- Amphetamine

replaces sulfhydryl group and is made into monoethyl

ester as a prodrug (Patchett 1984). After enalapril

enters the body, it can be metabolized into Enalapril

to exert its efficacy, which was later listed by Merck

in the United States.

4.2 Description of Drug Targets and

How Their Function is Affected by

the Drugs

4.2.1 Pharmacology of Amlodipine

Calcium ion plays an important role in the excitation-

contraction coupling of the myocardium and vascular

smooth muscle. The higher the concentration of

calcium ions entering the cell, the stronger the

contractility of the myocardium and vascular smooth

muscle (Bers 2014). The entry of calcium ions into

cells mainly depends on the calcium channels on the

cell membrane. Calcium channels play an important

physiological role in the body and can be divided into

many subtypes (Zamponi, et al. 2015). The calcium

channels distributed in the cells of the cardiovascular

system are mainly L-type calcium channels.

Amlodipine is the third generation

dihydropyridine (DHP) calcium channel blocker

(CCB). Dihydropyridine drugs mainly inhibit L-type

Ca2 + voltage-gated calcium channels widely

distributed in the cell membrane of the cardiovascular

system (Gao, and Yan 2021), prevent calcium influx,

and inhibit the contractility of myocardium and

vascular smooth muscle. In this way, the myocardial

contractility is weakened, the heart rate is slowed

down, the cardiac ejection is reduced, and the arterial

blood pressure is reduced.

The calcium ion channel consists of α1 subunit

that determines their characteristics and α2, δ, β, γ

subunits help regulate the function of calcium ion

channels (Catterall 2011). Calcium channel blockers

can combine with calcium ion channels when α1 is in

subunit inactivate condition to keep them inactive and

reduce the flow of calcium ions into cells. According

to Tang’s research (Tang, et al. 2016), amlodipine can

be combined with the dihydropyridine combined

pockets of Ca

Ab, and the crystal structure of the

Progress of Amlodipine and Enalapril in the Treatment of Hypertension

209

compound can well represent the state of Amlodipine

regulate calcium channels, as shown in the Figure 3.

Unlike non-dihydropyridine calcium channel

blockers (e.g. Verapamil, Diltiazem),

dihydropyridine drugs do not limit the internal flow

of calcium ions by blocking pores but act as a gated

regulator (Catterall, and Swanson, 2015).

Figure 3: Crystal Structure of Compound of Amlodipine

and Ca

Ab (Tang, et al. 2016).

The above is the traditional and recognized blood

pressure reduction mechanism of amlodipine. In

addition, recent studies have shown that amlodipine

can also regulate arterial blood pressure in other

ways. For example, amlodipine can inhibit the growth

of vascular smooth muscle, regulate phenotypic

conversion and reduce arterial blood pressure (Fang,

et al. 2019, Stepien, et al. 1998).

4.2.2 Pharmacology of Enalapril

Enalapril is an antihypertensive drug that acts on the

renin angiotensin system (RAS). It belongs to the

angiotensin converting enzyme inhibitor (ACEI). The

mechanism of ACEI lowers blood pressure is shown

in figure 4.

Figure 4: The mechanism of ACEI lowers blood pressure.

The renin angiotensin system (RAS) is an

important system of body fluid regulation in the

human body. It plays an important role in maintaining

the stability of cardiovascular function and the

balance of body fluid and electrolytes. However,

excessive activation of RAS will lead to pathological

phenomena such as hypertension and congestive

heart failure (Forrester, et al. 2018). Therefore, a

major idea for the treatment of hypertension is to

down-regulate the over-excited RAS.

Renin is a protease synthesized and secreted by renal

near globular cells. It can hydrolyze angiotensinogen

(a polypeptide) into angiotensin I (a decapeptide

molecule) (Fyhrquist, and Saijonmaa 2008).

Angiotensin I has no obvious biological activity and

has no obvious contractile effect on the heart and

vascular smooth muscle (Li, et al. 1979).

Angiotensin converting enzyme (ACE) can

catalyze the conversion of angiotensin I (Ang I) to

angiotensin II (Ang II). Angiotensin II is the strongest

vasoconstrictor in the angiotensin family, and it is a

polypeptide substance. It can act on the AT1 receptors

of the myocardium and vascular smooth muscle cells

to directly constrict blood vessels and cause an

increase in blood pressure (Peach, and Dostal 1990).

In addition, Ang II can also promote the secretion of

norepinephrine and aldosterone, thereby promoting

the effect of sympathetic nerves on blood vessels,

increasing the reabsorption of sodium ions and water,

increasing blood volume, and leading to increased

blood pressure (Schlaich, et al. 2005, Xanthakis, and

Vasan 2013, Yatabe, et al. 2011).

When ACE is combined with ACEI, it can make

ACE lose its catalytic activity, reduce the production

of AngⅡ, and relax blood vessels, thereby lowering

blood pressure. In addition, ACEI can also enhance

the effect of bradykinin (a substance that promotes

vasodilation), make it accumulate, and lower blood

pressure (Tom, et al. 2002).

4.3 Mode of Delivery

4.3.1 Delivery of Amlodipine

Amlodipine can be administered in many ways.

Different modes of administration have their unique

characteristics and adapt to the condition or disease

severity.

Amlodipine can be salted with benzenesulfonic

acid and maleic acid and administered orally. Tablet

is the most common oral dosage form in the market.

Although there are great differences in the activity of

S- and R- configuration, there is no significant

difference in the clinical effect between racemate and

ICHIH 2022 - International Conference on Health Big Data and Intelligent Healthcare

210

amlodipine with single S-configuration, and there are

no serious adverse reactions. Therefore, it is often

administered in the form of a racemate (Park, et al.

2006). Oral instant amlodipine tablet is suitable for

patients with dysphagia. After entering the mouth,

this tablet disintegrates rapidly and is absorbed by the

human body, but it has high requirements for the

palatability of the tablet (Fukui-Soubou, et al. 2011).

Layered tablets can release drugs at two different

release rates. The effect of oral nanoemulsion on the

target site is greatly improved compared with

ordinary oral tablets (Chhabra, et al. 2011).

In addition to oral administration, there is also a

form of intranasal administration. The biodegradable

polymer hydroxypropyl guar is used to make

amlodipine microspheres and penetrate the nasal

mucosa (Swamy, and Abbas 2011).

4.3.2 Delivery of Enalapril

Enalapril is characterized as an oral prodrug, which is

hydrolyzed and metabolized in the body to produce

enalaprilat to produce pharmacological activity

(Patchett 1984). The process of hydrolyze and

metabolize is shown in Figure 5.

Figure 5: The prodrug enalapril is hydrolyzed and metabolized into enalapril in the body.

Enalapril is mainly administered orally. Enalapril

maleate has a low degree of oral absorption, and the

active form produced by first-pass elimination is

greatly reduced. Existing studies have improved the

bioavailability of oral enalapril in a variety of ways.

Preparation of enalapril maleate suspended

microspheres to control drug release (Abbas, and

Alhamdany 2020). The cross-linked hard gelatin

capsules are prepared, and the pulse drug delivery

mode is designed to control the drug release rate

(Tosha, et al. 2015). The oral mucosa is designed to

adhere to the double-layer tablet to allow the drug to

be absorbed through the oral mucosa to prevent the

first-pass metabolism of the drug (Shah,

Gadhethariya, and Shah 2014).

4.4 Comparison of Amlodipine and

Enalapril

Amlodipine and enalapril are two drugs with different

action mechanisms. Amlodipine belongs to

dihydropyridine calcium channel antagonist, and

enalapril belongs to angiotensin converting enzyme

inhibitor ACEI. Because of their different

mechanisms of action, they will have different effects

on patients with hypertension.

From the perspective of pharmacological action,

amlodipine can increase cardiac output, but enalapril

has no significant change in cardiac output (Murdoch,

and Heel 1991, Todd, and Heel 1986). Amlodipine

increased the glomerular filtration rate, while

enalapril did not affect the glomerular filtration rate

(Murdoch, and Heel 1991, Todd, and Heel 1986). In

known experiments, amlodipine has the effect of

antiplatelet aggregation, but enalapril has no such

effect (Hernández-Hernández, et al. 1999).

Amlodipine can decrease the demand for oxygen of

the myocardium and increase the protective effect on

the myocardium (Murdoch, and Heel 1991). Enalapril

can reverse the symptoms of cardiac hypertrophy in

patients with left ventricular hypertrophy (Todd, and

Heel 1986).

From the perspective of metabolism, the oral

absorption of amlodipine is slow, reaching the peak

of drug plasma concentration in 6 ~ 12 hours, and the

oral absorption of enalapril is rapid, reaching the peak

Progress of Amlodipine and Enalapril in the Treatment of Hypertension

211

in only one hour (Murdoch, and Heel 1991, Todd, and

Heel 1986).

From the perspective of adverse reactions, the

common adverse reactions of amlodipine include

edema, muscle spasm, and so on (Galappatthy, et al.

2016). The common adverse reaction of enalapril is

cough, which is a common adverse reaction in ACEI

(Simon, et al. 1992).

From an application point of view, the

combination of calcium channel antagonists and

ACEI in the treatment of hypertension can better

protect the cardiovascular system (Taddei 2015).

5 DISCUSSION OF DRUG

ECONOMICS

5.1 Cost of Amlodipine and Enalapril

According to the data of clincalc.com, in 2018, the

average total drug cost of amlodipine in the United

States was $24.71 per prescription, the average out-

of-pocket cost of patients was $4.79 per prescription,

and the daily treatment cost (i.e., the average cost of

each prescription divided by the number of days

required for treatment, the same below) was

$0.11/day. In the same year, the average total drug

cost of enalapril maleate (the maleate of enalapril) in

the United States was $42.88 per prescription, the

average out-of-pocket cost of patients was $11.29 per

prescription, and the daily treatment cost was

$0.24/day (Enalapril Maleate Drug Usage Statistics,

United States 2021). In contrast, the price of enalapril

maleate is higher than that of amlodipine.

Compare the prices of amlodipine in China and

the United States, unifying the purchase price of

patients as USD per tablet. Only in terms of the price

of tablets, the cost paid by Chinese patients with

hypertension is 2.3 times that of American patients

(Bai, et al. 2018).

5.2 The Number of Prescriptions and

Sales

In 2018, the number of prescriptions for amlodipine

exceeded 75 million, ranking fifth among prescription

drugs in the United States, and it has maintained its top

ten rankings in the past ten years, indicating that

amlodipine has been used in huge amounts. The

number of patients using amlodipine reached

15,851,641. Since 2008, the number of patients using

amlodipine and the number of prescriptions has been

slowly increasing (Amlodipine Drug Usage Statistics

2021).

Enalapril ranks 135th in the ranking of

prescription drugs in the United States, with more

than 5 million prescriptions and an estimated number

of patients of 1.07 million. Unlike amlodipine, since

2008, the number of enalapril prescriptions and the

number of patients has shown a downward trend, and

the ranking of commonly used prescription drugs in

the United States has also been declining in recent

years (Enalapril Maleate Drug Usage Statistics,

United States 2021).

Calcium channel blockers and β-blockers are the

most prescribed drugs for hypertension. At the same

time, in the treatment of elderly hypertensive patients,

amlodipine is the most common drug, reaching 37%

(Altaf, et al. 2014). In China, the defined daily dose

of CCB in the five years from 2007 to 2015 accounted

for about 42.8% of the five types of antihypertensive

drugs, with an average annual growth rate of about

13.2%. In China, in the five years from 2007 to 2015,

the defined daily dose of ACEI accounted for

approximately 13.3% of the five types of

antihypertensive drugs, with an average annual

growth rate of approximately 1.4% (Xu, et al. 2015).

6 CONCLUSIONS

Hypertension is widely concerned all over the world

because of its prevalence, difficulty to cure, and great

harm. The pathogenesis of hypertension is not clear,

but one of the possible trends in the research on the

pathogenesis of hypertension is integration, that is,

considering the cumulative effect of multiple factors,

such as eating habits, gene inheritance, and

microbiota. At present, the exploration of the possible

pathogenic factors of hypertension is not exhaustive.

However, based on the correlation between the

known important pathogenic factors and the

incidence rate of hypertension, a rough model can be

established, which is important for preventing and

controlling hypertension.

In the treatment of hypertension, amlodipine, a

calcium channel blocker, and enalapril, an

angiotensin converting enzyme inhibitor, have

antihypertensive effects through different

pharmacological effects. The research on the

potential pharmacological mechanism of known

drugs plays an important role in deeply understanding

the pathogenesis and developing new targeted drugs.

In recent studies on the discovery and research of new

antihypertensive mechanisms of two drugs,

amlodipine can regulate the configuration conversion

of vascular smooth muscle to reduce blood pressure,

ICHIH 2022 - International Conference on Health Big Data and Intelligent Healthcare

212

and the targets and real compounds that promote the

configuration conversion are good research objects.

For the antihypertensive drug market, the number of

patients using amlodipine to reduce blood pressure is

increasing year by year, which will promote the in-

depth study of amlodipine. For other types of

antihypertensive drugs, to occupy a larger market

share, enterprises are required to optimize the

production process and improve antihypertensive

drugs and develop drugs or dosage forms with better

efficacy, safety, and stability, and appropriate price.

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