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The most common and widely used name for this substance is Gemcitabine Hydrochloride, which is its generic name.
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1. Basic Information
· CAS Number: 31592-08-2
· Chemical Name:
· (2'R)-2'-Deoxy-2',2'-difluorocytidine hydrochloride (β-isomer)
· 4-Amino-1-(2-deoxy-2,2-difluoro-β-D-ribofuranosyl)-1H-pyrimidine-2-one hydrochloride
· Molecular Formula: C₉H₁₁F₂N₃O₄ · HCl
· Molecular Weight: 299.66 (for gemcitabine free base) + 36.46 (for HCl) ≈ 336.12 g/mol
· Appearance: Usually a white to off-white crystalline powder.
2. Chemical Structure and Properties
Gemcitabine hydrochloride is the hydrochloride form of the nucleoside analogue gemcitabine. The structure of gemcitabine is very similar to the naturally occurring nucleoside - deoxycytidine, with the key difference being that two hydrogen atoms on the sugar ring are replaced by fluorine atoms (i.e., "difluoride"). This structural modification enables it to "deceive" cells, allowing them to be taken up and phosphorylated by the cells, but ultimately it will interrupt the DNA synthesis process.
The reason for preparing it in the form of hydrochloride is mainly to increase the solubility and stability of the drug in water, making it easier to be formulated into an injection.
3. Pharmacological Effects and Clinical Applications
Mechanism of action:
Gemcitabine hydrochloride is an anti-metabolic cancer drug. Its mechanism of action is very classic and highly effective, mainly consisting of two steps:
1. Incorporation into DNA strand: Gemcitabine is converted into the active triphosphate form (dFdCTP) within the cell. During DNA replication, it can replace the normal nucleotide (dCTP) and be incorporated into the newly synthesized DNA strand.
2. Termination of DNA synthesis: After gemcitabine is incorporated into the DNA strand, adding a normal nucleotide will cause the synthesis of the DNA strand to stop. This process is called "masked chain termination". The cell cannot recognize and repair this error, resulting in cell cycle arrest (mainly in the S phase) and ultimately triggering cell apoptosis (programmed death).
Main indications:
Gemcitabine hydrochloride is a very important first-line chemotherapy drug in clinical practice, and is mainly used for the treatment of:
· Local advanced or metastatic pancreatic cancer: It is one of the standard first-line treatment drugs for advanced pancreatic cancer, which can be used alone or in combination with albumin paclitaxel.
· Local advanced or metastatic non-small cell lung cancer: It is usually used in combination with platinum-based drugs (such as cisplatin or carboplatin).
· Advanced bladder cancer: It is usually used in combination with cisplatin.
· Advanced ovarian cancer, breast cancer, etc.: It is also used for the treatment of other solid tumors, usually as part of combined chemotherapy.
4. Administration method and dosage
· Administration route: Intravenous infusion. Oral administration or intramuscular injection is not allowed.
· Dosage: Determined based on the patient's body surface area (mg/m²), cancer type, disease stage, liver and kidney function, as well as the combined treatment regimen with other drugs. There is a significant individual variation. The treatment is usually carried out in cycles (for example, once a week for three consecutive weeks, followed by a one-week rest).
5. Main adverse reactions
Like most chemotherapy drugs, gemcitabine hydrochloride not only kills cancer cells but also affects normal cells that divide rapidly. As a result, it causes a series of side effects. Common ones include:
· Bone marrow suppression: This is the most common dose-limiting toxicity. It manifests as decreased white blood cells, reduced platelets, and anemia, increasing the risks of infection and bleeding.
· Flu-like symptoms: Fever, fatigue, headache, muscle pain, etc.
· Gastrointestinal reactions: Nausea, vomiting, loss of appetite, diarrhea.
· Liver function abnormalities: Elevated transaminase levels, etc.
· Renal toxicity: Proteinuria and hematuria may be observed.
· Pulmonary toxicity: Rare but severe, it may cause interstitial pneumonia and breathing difficulties.
· Rash and peripheral edema.
6. Important Notes
· It must be used under the guidance of experienced oncologists.
· During the treatment, close monitoring of blood routine, liver and kidney functions is required.
· Those who are allergic to the drug ingredients should avoid using it.
· Pregnant women and lactating women should not use it, as there is a risk of teratogenicity and harm to the fetus.
Summary

Gemcitabine hydrochloride (CAS 31592-08-2) is a highly important nucleoside analogue anti-tumor drug. It inhibits DNA synthesis through a unique "masking chain termination" mechanism, effectively killing rapidly proliferating cancer cells. Since its launch, it has become a cornerstone drug for treating various malignant tumors such as pancreatic cancer, non-small cell lung cancer, and bladder cancer, saving countless patients' lives. However, its significant side effects such as severe bone marrow suppression require strict monitoring and management during clinical use.