Cimetidine API Manufacturer China | ≥98% H2 Receptor Antagonist Pharmaceutical Powder CAS 51481-61-9

Key Selling Points

✓ First-in-Class H2 Receptor Antagonist - Original Clinical H2 Blocker (Tagamet, 1970s)

✓ Strong CYP450 Inhibitor - Inhibits CYP1A2/2C9/2D6/3A4, Widely Used in Drug Interaction Research

✓ Antiandrogenic & Immunomodulatory - Unique Androgen Receptor Antagonism + T-Cell Immune Enhancement

✓ Well-Established Veterinary GI API - Canine (Zitac vet), Feline & Equine Gastric Ulcer / Hyperacidity

✓ No NDMA Concern - Unlike Ranitidine, Cimetidine Has No Nitrosamine Impurity Issue

✓ Research-Grade API - ≥98% HPLC, Full COA, Identity & Impurity Documentation

What Is Cimetidine Powder?

Cimetidine Powder (CAS 51481-61-9, C₁₀H₁₆N₆S, MW 252.34) is the first-generation histamine H2 receptor antagonist (H2RA) developed in the 1970s. It competitively blocks H2 receptors on gastric parietal cells, reducing gastric acid secretion triggered by histamine, food and other stimulants.

Cimetidine is widely used as a pharmaceutical and research raw material for gastric ulcer, duodenal ulcer, GERD, Zollinger-Ellison syndrome and acid-related disorders. It is also used in veterinary applications, including gastric ulcer and reflux-related conditions in dogs, cats and horses.

Unlike newer H2 blockers, cimetidine has strong cytochrome P450 enzyme inhibition activity, which may cause drug interactions. It also has antiandrogenic and immunomodulatory properties.

How Does Cimetidine Powder Work?

Cimetidine Powder works by reversibly blocking histamine H2 receptors on gastric parietal cells. This reduces cAMP signaling and decreases activation of the H⁺/K⁺-ATPase proton pump, resulting in lower gastric acid production and reduced pepsin activity.

Cimetidine has an oral bioavailability of approximately 60–70% and is mainly eliminated through urine. Due to CYP450 inhibition, it may interact with drugs such as warfarin, phenytoin and theophylline. Common side effects include headache, dizziness and gastrointestinal discomfort.

What Are the Applications of Cimetidine Powder?

Human Medicine: Used in research and formulations related to gastric ulcer, duodenal ulcer, GERD, reflux esophagitis, Zollinger-Ellison syndrome and gastric acid hypersecretion disorders.
Veterinary Applications: Used for gastric ulcer, gastritis, reflux-related conditions and gastric acid disorders in dogs, cats and horses.
Drug Interaction Research: Applied in CYP450 inhibition studies, drug-drug interaction models and pharmacokinetic research.
Pharmacology Research: Used in studies of gastric acid secretion, H2 receptor mechanisms, immune modulation and antiandrogenic effects.
Pharmaceutical Manufacturing: Serves as a raw material for tablets, oral solutions, compounded preparations and other dosage forms.

What Is the Difference Between Cimetidine and Other H2 Antagonists?

Feature	Cimetidine	Ranitidine	Famotidine	Nizatidine
CAS	51481-61-9	66357-59-3 (HCl)	76824-35-6	76963-41-2
Ring Structure	Imidazole	Furan	Thiazole	Thiazole
Potency (vs cimetidine)	1× (reference)	5–8×	20–50×	5–10×
CYP450 Inhibition	Strong (1A2, 2C9, 2D6, 3A4)	Minimal	None	Minimal
Antiandrogenic Effects	Yes (gynecomastia)	Rare	None	None
Immunomodulatory	Yes (T-cell enhancement)	No	No	No
Oral Bioavailability	60–70%	~50%	40–50%	~90%+
Half-life	~2 h	2–3 h	2.5–4 h	1–2 h
NDMA Issue	No	Yes (2020 withdrawal)	No	Yes (2020 recall)
Veterinary Product	Zitac vet (dogs)	Limited	Most common	Limited
Drug Interactions	Very numerous	Few	Minimal	Few

How Does Cimetidine Compare With Proton Pump Inhibitors (PPIs)?

Feature	Cimetidine (H2RA)	Omeprazole (PPI)	Pantoprazole (PPI)
CAS	51481-61-9	73590-58-6	102625-70-7
Mechanism	H2 receptor antagonism (reversible)	Irreversible H+/K+-ATPase inhibition	Irreversible H+/K+-ATPase inhibition
Onset	Fast (30–60 min)	Slow (1–3 days)	Slow (1–3 days)
Acid Suppression	Moderate, short-acting	Very strong, 24 h+	Very strong, 24 h+
Tolerance	Yes (rapid tachyphylaxis)	Minimal	Minimal
CYP450 Interaction	Strong (multiple isoenzymes)	Moderate (CYP2C19)	Minimal
Nocturnal Acid	Good	Moderate	Moderate
Typical Use	Intermittent acid, ulcer healing, drug interaction research	Severe GERD, ulcer, H. pylori, Z-E	Severe GERD, hospital IV, ulcer

How Is Cimetidine Powder Manufactured?

Cimetidine Powder is manufactured through multi-step chemical synthesis involving imidazole ring construction, thiomethyl linkage, cyanoguanidine formation and purification.

Raw Material QC → Starting Material (2-Chloro-5-methylimidazole / 2-[(5-Methyl-1H-imidazol-4-yl)methylthio]ethylamine) → Cyanoguanidine Condensation (N-Cyano-N'-methylisothiourea) → Crude Cimetidine → Purification (Recrystallization) → Drying → Milling → Final QC → Packaging

HDM BIO controls key condensation, recrystallization and drying parameters to maintain consistent purity, particle size and batch quality.

Quality Specifications

Test Item	Standard	Typical Result
Appearance	White to off-white powder	Consistent
Assay (HPLC)	≥98.0%	99.0%
Identity (IR / HPLC)	Conforms to reference standard	Confirmed
Melting Point	139–144°C	141°C
Loss on Drying	≤0.5%	0.2%
Residue on Ignition	≤0.1%	0.05%
Related Substances	Within specification	Pass
Heavy Metals	≤10 ppm	Compliant
Residual Solvents	Within specification	Pass
Sterility (injectable grade)	Sterile	Compliant
Bacterial Endotoxins (injectable grade)	≤0.5 EU/mg	Compliant

What Quality Control Tests Are Performed for Cimetidine Powder?

Each batch undergoes multi-step quality control before release to verify identity, purity and key quality attributes.

Raw Material QC → In-Process Control → HPLC Assay → IR Identity Verification → Melting Point Determination → Loss on Drying → Residue on Ignition → Related Substances (HPLC) → Heavy Metals → Residual Solvents → Sterility Test (injectable grade) → Bacterial Endotoxin Test (LAL, injectable grade) → Final Batch Release

Key evaluations include HPLC assay (≥98%), IR identity, melting point, loss on drying, residue on ignition, related substances, heavy metals, residual solvents, and for injectable grade: sterility and bacterial endotoxin (LAL) testing. Every commercial batch is supported by a batch-specific COA and relevant analytical documentation for incoming QC and supplier qualification.

What Factors Affect Cimetidine Powder Bulk Price?

Cimetidine Powder bulk pricing is driven by several key factors:

Raw Material Costs: Imidazole derivatives and cyanoguanidine starting materials directly influence manufacturing expenses.
Purity & Grade: Injectable grade (sterile, endotoxin-controlled, ≥98%) commands a significant premium over oral/technical grade.
Sterility & Endotoxin Specification: Aseptic processing and LAL-tested batches for injection carry higher production costs.
Regulatory Compliance & Certification: GMP-standard API with consistent COA demands a higher price.
Order Volume: Large-scale pharmaceutical contracts receive steeper per-kilogram discounts.
Logistics & Geography: Light-protected / moisture-proof packaging and customs compliance add to the landed cost.

Contact HDM BIO for a current quotation and volume-based pricing.

Why Choose HDM BIO as Your Cimetidine Powder Supplier?

High-purity (≥98% / typical 99%) first-in-class H2 receptor antagonist API for tablet, syrup and injectable formulation research
Verified consistent melting point, low related substances and reliable quality
Unique multi-pharmacology profile: strong CYP450 inhibition, antiandrogenic and immunomodulatory effects
No NDMA nitrosamine impurity concern (unlike ranitidine)
GMP-aligned production, ISO & HACCP certified quality system
Full batch traceability and complete documentation (COA, MSDS, HPLC, sterility, LAL)
Flexible supply: kilogram samples to ton-level bulk API orders
Global export to 70+ countries with full customs support

Bulk Packaging, Shipping & Storage

Packaging: Foil bags for samples and moisture-proof fiber drums for bulk orders.
Custom Packaging: OEM labeling available.
Shipping Documents: COA, MSDS/SDS, commercial invoice, packing list and customs documentation available according to order requirements.
Storage: Store tightly sealed in a cool, dry, light-protected environment. Shelf life: 24 months.
Handling: For pharmaceutical/veterinary raw material use only; not for direct clinical administration.

Frequently Asked Questions About Cimetidine Powder

Q1: What is Cimetidine Powder?

A: Cimetidine is the first-in-class histamine H2 receptor antagonist (H2RA), originally marketed as Tagamet in the 1970s. It competitively blocks H2 receptors on gastric parietal cells, reducing basal and stimulated gastric acid secretion. Used for gastric/duodenal ulcer, GERD, Zollinger-Ellison syndrome. Uniquely, it is a strong CYP450 inhibitor, has antiandrogenic effects (gynecomastia) and immunomodulatory activity. No NDMA concern.

Q2: What is the CAS number?

A: 51481-61-9 (free base); hydrochloride salt CAS 70059-30-2.

Q3: How does cimetidine work?

A: It competitively and reversibly antagonizes histamine H2 receptors on gastric parietal cells, reducing cAMP and proton pump activation, thereby decreasing gastric acid output, volume and pepsin. It does not affect gastric emptying. It also strongly inhibits CYP450 (1A2, 2C9, 2D6, 3A4), reduces hepatic blood flow, and antagonizes androgen receptors. Oral bioavailability ~60–70%; half-life ~2 h; continuous use causes tolerance.

Q4: What is cimetidine used for?

A: Human: gastric/duodenal ulcer, GERD, Zollinger-Ellison, gastrinoma, mastocytosis hyperacidity, stress ulcer prophylaxis. Veterinary: canine gastric ulcer/chronic gastritis (Zitac vet), feline reflux, equine EGUS. Research: CYP450 drug interaction models, immunology/oncology (T-cell enhancement), endocrinology (antiandrogen), GI ulcer models.

Q5: Does cimetidine have NDMA issues like ranitidine?

A: No. Unlike ranitidine (which was withdrawn from the U.S. and EU markets in 2020 due to NDMA nitrosamine impurity), cimetidine does not have a known NDMA formation problem. Its imidazole ring structure is chemically stable and does not degrade to nitrosamines under normal storage conditions.

Q6: What are the main drug interactions with cimetidine?

A: Cimetidine strongly inhibits CYP1A2, CYP2C9, CYP2D6 and CYP3A4, and reduces hepatic blood flow. It increases levels of: warfarin (bleeding risk), theophylline (toxicity), phenytoin (CNS toxicity), lidocaine, quinidine, propranolol, metoprolol, benzodiazepines (diazepam), calcium channel blockers and tricyclic antidepressants. Dose adjustment or therapeutic monitoring is required when co-administering these drugs.

Q7: What purity do you supply?

A: Standard ≥98.0% HPLC; typical batch result 99%. Injectable grade with sterility and endotoxin specification available on request.

Q8: Where can I buy it from China?

A: HDM BIO supplies bulk Cimetidine Powder with batch COA and global export support.

Q9: Are there any safety concerns?

A: Cimetidine Powder is generally well tolerated. Common side effects include headache, dizziness, diarrhea, constipation and rash. Long-term or high-dose use may cause antiandrogenic effects, such as gynecomastia and reduced libido. Rare reactions include confusion, liver enzyme changes, blood cell abnormalities and bradycardia. Due to strong CYP450 inhibition, cimetidine may interact with many drugs. Dose adjustment is recommended for renal or hepatic impairment.

Q10: Is cimetidine still used in veterinary medicine?

A: Yes. Cimetidine is still used in veterinary research and some clinical applications for gastric ulcer, gastritis and acid-related disorders in dogs, cats and horses. However, newer H2 blockers such as famotidine are often preferred because they have fewer drug interactions, higher potency and longer duration of action.