Diltiazem API Manufacturer & Bulk Supplier in India | Swapnroop Drugs & Pharmaceuticals

Introduction

Diltiazem is an established cardiovascular pharmaceutical ingredient belonging to the benzothiazepine class of calcium channel blockers. It is used in prescription medicines for managing certain cardiovascular conditions, including hypertension, chronic stable angina and coronary artery spasm.

Its pharmacological action involves inhibiting the movement of calcium ions into cardiac and vascular smooth muscle cells. This helps relax blood vessels, reduce vascular resistance and influence the heart's electrical conduction and contractile activity.

Diltiazem is commonly formulated as Diltiazem Hydrochloride, which is used in several oral and injectable pharmaceutical products.

For pharmaceutical manufacturers, formulation developers, API procurement professionals and quality-control teams, evaluating Diltiazem API requires attention to chemical identity, stereochemical purity, assay, related substances, residual solvents, stability and applicable pharmacopoeial requirements.

Swapnroop Drugs & Pharmaceuticals (SDP) presents this technical overview for pharmaceutical professionals researching Diltiazem API, its pharmaceutical applications and its quality requirements.

What Is Diltiazem API?

Diltiazem is a calcium channel blocker belonging to the benzothiazepine chemical class. It inhibits the influx of extracellular calcium ions through voltage-dependent calcium channels, particularly in cardiac and vascular smooth muscle cells.

Calcium ions play an important role in muscle contraction and electrical activity. By reducing calcium entry into these cells, diltiazem produces several cardiovascular effects, including:

Relaxation of vascular smooth muscle
Dilatation of coronary and systemic arteries
Reduction in peripheral vascular resistance
Reduction in myocardial oxygen demand
Slowing of conduction through the atrioventricular node

The pharmaceutical ingredient is commonly used as Diltiazem Hydrochloride, a hydrochloride salt of the active diltiazem molecule.

Diltiazem API – Key Product Information

The following table distinguishes Diltiazem free base from the commonly used hydrochloride salt.

Parameter	Diltiazem Free Base	Diltiazem Hydrochloride
API Name	Diltiazem	Diltiazem Hydrochloride
CAS Number	42399-41-7	33286-22-5
Molecular Formula	C₂₂H₂₆N₂O₄S	C₂₂H₂₆N₂O₄S·HCl
Molecular Weight	Approximately 414.52 g/mol	Approximately 450.98 g/mol
Chemical Class	Benzothiazepine derivative	Benzothiazepine hydrochloride
Pharmacological Class	Calcium channel blocker	Calcium channel blocker
Stereochemistry	Defined cis stereochemistry	Defined cis stereochemistry
Physical Description	Confirm against the applicable material specification	White to off-white crystalline powder
Common Pharmaceutical Form	Not the usual labelled salt form	Oral tablets, extended-release capsules and injectable products

The molecular formula of Diltiazem Hydrochloride is also written as C₂₂H₂₇ClN₂O₄S.

Important chemical note: Diltiazem is a stereochemically defined compound. The pharmaceutical hydrochloride form is commonly identified as the (+)-cis form, with the relevant stereochemistry specified in official product labelling. The free-base and hydrochloride values must not be interchanged when preparing product specifications or interpreting analytical results.

The hydrochloride molecular weight is approximately 450.98–450.99 g/mol, depending on the stated rounding convention. <Cite refs={["turn633058search0","turn633058search1","turn633058search3","turn633058search8"]} />

Chemical Structure and Properties of Diltiazem

Diltiazem belongs to the 1,5-benzothiazepine family. Its molecular structure contains a seven-membered heterocyclic ring incorporating nitrogen and sulfur atoms.

Other structural features include:

A methoxy-substituted phenyl group
A dimethylaminoethyl side chain
An acetate functional group
Two defined stereochemical centres
A benzothiazepine ring system

The molecular formula of Diltiazem free base is C₂₂H₂₆N₂O₄S, while the hydrochloride salt has the formula C₂₂H₂₆N₂O₄S·HCl.

Official drug labelling describes Diltiazem Hydrochloride as a white to off-white crystalline powder with a bitter taste. It is soluble in water, methanol and chloroform.

These properties are relevant to API identification, formulation development, analytical testing, material handling and stability assessment.

Mechanism of Action of Diltiazem

Diltiazem produces its cardiovascular effects by inhibiting the influx of calcium ions through slow calcium channels.

1. Calcium Channel Inhibition

Diltiazem inhibits calcium ion entry into cardiac and vascular smooth muscle cells during membrane depolarization.

2. Vascular Smooth Muscle Relaxation

Reduced intracellular calcium availability decreases vascular smooth muscle contraction, promoting relaxation of blood vessels.

3. Reduction in Peripheral Vascular Resistance

Relaxation of systemic arteries helps reduce peripheral vascular resistance and contributes to its antihypertensive effect.

4. Effects on Cardiac Conduction

Diltiazem slows conduction through the atrioventricular node and can reduce heart rate in appropriate clinical settings.

5. Reduction in Myocardial Oxygen Demand

By reducing certain aspects of cardiac workload and dilating coronary arteries, diltiazem can help reduce myocardial oxygen demand.

These combined effects explain its use in selected cardiovascular conditions.

Pharmaceutical Applications of Diltiazem

Diltiazem is used in approved prescription medicines for several cardiovascular conditions.

1. Hypertension

Diltiazem is used in approved formulations for managing high blood pressure.

Its antihypertensive activity is primarily related to relaxation of vascular smooth muscle and reduction in peripheral vascular resistance.

2. Chronic Stable Angina

Diltiazem is used in the management of chronic stable angina.

By reducing cardiac workload and myocardial oxygen demand, it can help improve exercise tolerance in appropriately selected patients.

3. Coronary Artery Spasm

Diltiazem is used in approved products for angina associated with coronary artery spasm.

Its coronary vasodilatory activity helps reduce the effects of coronary vasoconstriction.

4. Certain Cardiac Arrhythmias

Intravenous diltiazem is used in selected clinical settings involving rapid ventricular rates associated with atrial fibrillation or atrial flutter.

It may also be used in the management of certain supraventricular tachycardias under appropriate medical supervision.

Clinical note: The approved indications depend on the formulation and regulatory market. Diltiazem is not suitable for every patient and requires attention to heart rate, blood pressure, cardiac conduction and potential drug interactions.

Pharmaceutical Formulations of Diltiazem

Diltiazem Hydrochloride is used in several pharmaceutical dosage forms.

Common presentations include:

Immediate-release oral tablets
Extended-release oral tablets
Extended-release capsules
Injectable formulations for intravenous administration

The choice of formulation depends on the intended clinical application and product approval.

Formulation Development Considerations

Pharmaceutical manufacturers developing Diltiazem formulations should evaluate:

API-excipient compatibility
Chemical and physical stability
Dissolution characteristics
Content uniformity
Release-profile consistency
Moisture sensitivity
Packaging compatibility
Stability during manufacturing and storage

Extended-release formulations require particular attention to drug-release performance and reproducibility throughout the product's shelf life.

Injectable formulations require additional controls relating to sterility, endotoxins, particulate matter and solution compatibility.

Quality Requirements for Diltiazem API

Quality assurance is essential when evaluating Diltiazem Hydrochloride because its chemical identity, stereochemistry, purity and stability influence the quality of the finished medicine.

1. Identification

Identification testing should confirm that the material corresponds to Diltiazem Hydrochloride.

Appropriate validated procedures may include infrared spectroscopy, chromatographic identification and other suitable analytical techniques.

2. Assay and Potency

The assay should establish the content of Diltiazem Hydrochloride using a validated analytical method.

The specification should clearly state the basis of calculation and the applicable pharmacopoeial requirements.

3. Related Substances

Related substances and degradation products should be evaluated using suitable validated analytical procedures.

Acceptance criteria should follow the applicable pharmacopoeial monograph and approved specification.

4. Stereochemical Purity

Diltiazem has defined stereochemistry. The specified cis stereochemical form should be confirmed and relevant stereochemical impurities controlled according to the applicable specification.

5. Residual Solvents

Residual solvents should be assessed in accordance with applicable ICH requirements and the approved material specification.

6. Water Content

Water content should be evaluated where required by the applicable material specification.

7. Stability

Stability studies should support the proposed retest period, packaging configuration and storage conditions. Stability conclusions should be based on actual material-specific data.

Analytical Testing and Quality Control

A suitable quality-control programme should follow the applicable pharmacopoeial monograph and approved product specification.

Potential testing areas include:

Description and appearance
Identification
Assay
Related substances
Stereochemical purity
Residual solvents
Water content, where specified
Stability-indicating analytical evaluation
Packaging integrity
Batch traceability

For injectable products, additional finished-product controls may include sterility, bacterial endotoxins and particulate matter testing.

Not every test is necessarily a routine release test for every API grade. The final testing panel and acceptance limits must be established from the applicable specification and regulatory commitments.

Documentation Required for Pharmaceutical Evaluation

Before qualifying a Diltiazem API source, pharmaceutical manufacturers and procurement teams should review relevant technical and quality documents.

Typical documentation includes:

Batch-specific Certificate of Analysis (COA)
Technical Data Sheet (TDS)
Safety Data Sheet (SDS)
Approved API specification
Analytical method information
Related-substances and impurity profile
Stereochemical purity information
Residual-solvent information, where applicable
Water-content information, where specified
Stability data and retest-period justification
Packaging and storage information
Manufacturing and quality-system documentation
Applicable regulatory declarations and supporting documents

The COA should clearly identify Diltiazem Hydrochloride and provide batch-specific analytical results.

Regulatory Considerations for Diltiazem API in India

Diltiazem is a prescription cardiovascular pharmaceutical ingredient. Its manufacture, import, distribution and use in finished medicines must comply with the applicable Indian drug regulatory framework.

Organizations evaluating the material should consider:

Applicable requirements under the Drugs and Cosmetics Act and Rules
Relevant manufacturing or import licences
Applicable pharmacopoeial standards
Approved API specifications
Quality-system and batch-traceability requirements
Finished-product approval and labelling requirements
Destination-market regulatory requirements for export products

Companies should confirm current regulatory requirements with relevant authorities and qualified regulatory professionals before undertaking commercial activities.

Factors to Consider When Evaluating a Diltiazem API Source

Pharmaceutical manufacturers and procurement teams should follow a documented supplier-qualification process.

Chemical identity: Confirm whether the material is Diltiazem free base or Diltiazem Hydrochloride.

Stereochemical identity: Verify that the material meets the required stereochemical specification.

Analytical quality: Review the batch-specific COA, assay results, related-substances profile and validated analytical methods.

Pharmacopoeial compliance: Confirm the applicable grade and current approved specification.

Stability and packaging: Evaluate supporting stability information, storage conditions and packaging suitability.

Quality management: Review batch traceability, deviation management, change control and complaint-handling procedures.

Regulatory documentation: Verify that the supplier and other relevant parties hold the permissions required for the intended activity and market.

Diltiazem API Enquiries – Swapnroop Drugs & Pharmaceuticals

Swapnroop Drugs & Pharmaceuticals (SDP) provides pharmaceutical industry information and supports business enquiries relating to pharmaceutical APIs and raw materials.

For Diltiazem API enquiries, pharmaceutical organizations should specify the required chemical form, grade, applicable pharmacopoeial standard, intended market and documentation requirements.

The product documentation should clearly identify whether the material is Diltiazem free base or Diltiazem Hydrochloride. Any discussion of sourcing or availability is subject to verification of the exact product, current availability, quality documentation and applicable regulatory permissions.

Frequently Asked Questions (FAQs)

1. What is Diltiazem API?

Diltiazem API is a cardiovascular pharmaceutical ingredient belonging to the benzothiazepine class of calcium channel blockers. It is commonly used in the hydrochloride salt form.

2. What is the CAS number of Diltiazem?

The CAS number for Diltiazem free base is 42399-41-7. Diltiazem Hydrochloride is identified by CAS number 33286-22-5.

3. What is the molecular formula of Diltiazem?

The molecular formula of Diltiazem free base is C₂₂H₂₆N₂O₄S. The hydrochloride salt is represented as C₂₂H₂₆N₂O₄S·HCl.

4. What is the molecular weight of Diltiazem?

Diltiazem free base has a molecular weight of approximately 414.52 g/mol. Diltiazem Hydrochloride has a molecular weight of approximately 450.98 g/mol.

5. What is the pharmacological class of Diltiazem?

Diltiazem belongs to the non-dihydropyridine calcium channel blocker class and is chemically classified as a benzothiazepine derivative.

6. How does Diltiazem work?

Diltiazem inhibits calcium ion influx into cardiac and vascular smooth muscle cells. This produces vascular relaxation and influences cardiac conduction and contractile activity.

7. What are the pharmaceutical applications of Diltiazem?

Diltiazem is used in approved medicines for hypertension, chronic stable angina and coronary artery spasm. Certain intravenous formulations are used in selected cardiac rhythm-related conditions.

8. Which dosage forms contain Diltiazem Hydrochloride?

Common dosage forms include immediate-release tablets, extended-release tablets, extended-release capsules and injectable formulations.

9. Why is stereochemical purity important for Diltiazem API?

Diltiazem has defined stereochemical centres. The specified cis form is important for pharmaceutical identity, so relevant stereochemical impurities must be controlled.

10. What quality tests are relevant for Diltiazem API?

Relevant tests may include identification, assay, related substances, stereochemical purity, residual solvents, water content and stability-indicating analysis.

11. What documents should be reviewed before qualifying a Diltiazem API source?

Companies should review the batch-specific COA, approved specification, TDS, SDS, analytical information, impurity profile, stability support and applicable regulatory documents.

12. What should buyers confirm before making a Diltiazem API enquiry?

Buyers should confirm the chemical form, grade, CAS number, molecular-weight basis, applicable specification, intended market and supporting quality documentation.

Conclusion

Diltiazem is an important cardiovascular pharmaceutical ingredient belonging to the benzothiazepine class of calcium channel blockers. It is used in approved medicines for hypertension, angina and selected cardiac rhythm-related conditions.

Its pharmaceutical evaluation requires attention to chemical identity, stereochemistry, assay, related substances, residual solvents, stability and applicable quality documentation.

The distinction between Diltiazem free base and Diltiazem Hydrochloride is important because their molecular formulas, CAS numbers and molecular weights differ. Pharmaceutical manufacturers and procurement teams should verify the exact chemical form and approved specification before qualifying the material for formulation or commercial use.

Swapnroop Drugs & Pharmaceuticals welcomes legitimate pharmaceutical business enquiries relating to Diltiazem API, subject to verification of product details, availability and applicable regulatory requirements.