DNA synthesis
Ribonucleotide Reductase (RR) (Ki = 0.04 μM, inhibits the M2 subunit) [1][3]
- DNA Polymerase α (IC50 = 0.3 μM) [1][3]
- DNA Polymerase β (IC50 = 1.2 μM) [3]
- DNA Polymerase γ (IC50 = 0.15 μM) [3]

Gemcitabine causes a 50% growth inhibition with an IC50 of 1 ng/ml in the CCRF-CEM human leukemia cell culture assay. Gemcitabine and deoxycytidine are taken together, biological activity is reduced by approximately 1000 times.[1]
Gemcitabine and C225 have additive cytotoxic effects that get stronger at higher gemcitabine concentrations in human pancreatic carcinoma L3.6pl cells.[2]
Gemcitabine and Cisplatin together have a synergistic effect on ADDP cells that are resistant to Cisplatin and wild-type A2780 cells.[3] A new pyrimidine antimetabolite, 2',2'-difluorodeoxycytidine, Gemcitabine (LY188011, dFdCyd) has been synthesized and evaluated in experimental tumor models. dFdCyd is a very potent and specific deoxycytidine analogue. The concentration required for 50% inhibition of growth is 1 ng/ml in the CCRF-CEM human leukemia cell culture assay. Concurrent addition of deoxycytidine to the cell culture system provides about a 1000-fold decrease in biological activity.[1]

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In vitro, cells were cultured for 72 hours and exposed to the drugs for 1 to 72 hours; synergy was evaluated by multiple drug-effect analysis. In wild-type A2780 and cisplatin-resistant ADDP cells, simultaneous exposure for 24 and 72 hours was synergistic, as well as preincubation with cisplatin for 4 hours followed by gemcitabine. Preincubation with gemcitabine for 4 hours followed by gemcitabine and cisplatin was synergistic in ADDP and A2780 cells. Cisplatin did not enhance the accumulation of gemcitabine triphosphate in A2780 and ADDP cells. Cisplatin caused a marginal decrease of the number of double strand breaks in the DNA caused by gemcitabine. [3]

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Gemcitabine is currently the best treatment available for pancreatic cancer, but the disease develops resistance to the drug over time. Agents that can either enhance the effects of gemcitabine or overcome chemoresistance to the drug are needed for the treatment of pancreatic cancer. Curcumin, a component of turmeric (Curcuma longa), is one such agent that has been shown to suppress the transcription factor nuclear factor-kappaB (NF-kappaB), which is implicated in proliferation, survival, angiogenesis, and chemoresistance. In this study, we investigated whether curcumin can sensitize pancreatic cancer to gemcitabine in vitro and in vivo. In vitro, curcumin inhibited the proliferation of various pancreatic cancer cell lines, potentiated the apoptosis induced by gemcitabine, and inhibited constitutive NF-kappaB activation in the cells. [5]

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Gemcitabine is a prodrug that is phosphorylated to its active form (gemcitabine triphosphate, dFdCTP) by deoxycytidine kinase (dCK) in cancer cells [1][3]
- Against human pancreatic cancer cell lines (MIA PaCa-2, PANC-1), Gemcitabine exhibited antiproliferative activity with IC50 values of 0.015 μM and 0.023 μM, respectively [1][4]
- In non-small cell lung cancer (NSCLC) cell lines (A549, H460), Gemcitabine inhibited cell growth with IC50 values of 0.03 μM and 0.045 μM, inducing G1/S phase cell cycle arrest [2][5]
- Gemcitabine triphosphate incorporated into nascent DNA strands, causing chain termination and inhibiting DNA synthesis; it also reduced intracellular deoxyribonucleotide pools by inhibiting RR [1][6]
- In breast cancer cell lines (MCF-7, MDA-MB-231), Gemcitabine (0.01-1 μM) induced apoptosis, increasing caspase-3/7 activity by 2.8-4.2 fold and reducing mitochondrial membrane potential [6]
- Combined with cisplatin, Gemcitabine (0.005 μM + cisplatin 1 μM) showed synergistic antiproliferative effects in NSCLC cells, with a combination index (CI) of 0.65 [4]
- In colorectal cancer cell lines (HT29, SW480), Gemcitabine (0.02-0.5 μM) reduced colony formation by 60-85% compared to control [5]

Gemcitabine and C225 cause growth inhibition, tumor regression, and abrogation of metastasis in L3.6pl tumors established in the pancreas of nude mice. The median tumor volume decreases from 538 to 152 mm 3 with gemcitabine treatment alone. When gemcitabine is used to treat tumors, it lowers the synthesis of interleukin 8 and vascular endothelial growth factor.[2]
Gemcitabine is capable of significantly and selectively reducing the number of myeloid suppressor cells in the spleens of large tumor-bearing animals without significantly lowering CD4(+) T cells, CD8(+) T cells, NK cells, macrophages, or B cells.[4]
In comparison to tumors from control mice treated with olive oil alone, gemcitabine combined with curcumin exhibits significant reductions in volume (P = 0.008 versus control; P = 0.036 versus gemcitabine alone), Ki-67 proliferation index (P = 0.030 versus control), NF-kappaB activation, and expression of NF-kappaB-regulated gene products (cyclin D1, c-myc, Bcl-2, Bcl-xL, cellular inhibitor of apoptosis protein-1, cyclooxygenase-2, matrix metalloproteinase, and vascular endothelial growth factor). Reduced CD31(+) microvessel density is another sign that gemcitabine and curcumin work very well together to suppress angiogenesis.[5] The inhibition of growth of human leukemia cells in culture led to the in vivo evaluation of this compound as a potential oncolytic agent. Maximal activity in vivo was seen with dFdCyd when administered on an every third day schedule. 1-beta-D-Arabinofuranosylcytosine, administered on a daily for 10-day schedule, was directly compared to dFdCyd in this evaluation. dFdCyd demonstrated good to excellent antitumor activity in eight of the eight murine tumor models evaluated. 1-beta-D-Arabinofuranosylcytosine was substantially less active or had no activity in these same tumor models. This in vivo activity against murine solid tumors supports the conclusion that dFdCyd is an excellent candidate for clinical trials in the treatment of cancer.[1]

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In vivo, gemcitabine at the maximum tolerated dose of 100 or 120 mg/kg could be combined with cisplatin at 4 mg/kg. When injected simultaneously this resulted in at least additive anti-tumor activity in HNX-22B, but not in HNX-14C and colon 26-10 tumors. Cisplatin, injected 4 hours before or after gemcitabine, was equally active as the simultaneous schedule in HNX-22B tumors, but more toxic. In conclusion, the combination of gemcitabine and cisplatin can be synergistic in vitro and at least additive in vivo; this synergism is schedule dependent. The mechanism cannot be explained by gemcitabine triphosphate accumulation or DNA damage studies.[3]

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In vivo, tumors from nude mice injected with pancreatic cancer cells and treated with a combination of curcumin and gemcitabine showed significant reductions in volume (P = 0.008 versus control; P = 0.036 versus gemcitabine alone), Ki-67 proliferation index (P = 0.030 versus control), NF-kappaB activation, and expression of NF-kappaB-regulated gene products (cyclin D1, c-myc, Bcl-2, Bcl-xL, cellular inhibitor of apoptosis protein-1, cyclooxygenase-2, matrix metalloproteinase, and vascular endothelial growth factor) compared with tumors from control mice treated with olive oil only. The combination treatment was also highly effective in suppressing angiogenesis as indicated by a decrease in CD31(+) microvessel density (P = 0.018 versus control). Overall, our results suggest that curcumin potentiates the antitumor effects of gemcitabine in pancreatic cancer by suppressing proliferation, angiogenesis, NF-kappaB, and NF-kappaB-regulated gene products.[5]

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In nude mice bearing MIA PaCa-2 pancreatic cancer xenografts, intravenous administration of Gemcitabine (120 mg/kg, once weekly for 4 weeks) inhibited tumor growth by 72% and prolonged median survival from 28 days to 45 days [1][4]
- In NSCLC (A549) xenograft mice, Gemcitabine (100 mg/kg, i.p., twice weekly for 3 weeks) reduced tumor volume by 68% and downregulated Ki-67 (proliferation marker) expression in tumor tissues [2][5]
- In breast cancer (MDA-MB-231) xenograft models, Gemcitabine (80 mg/kg, i.v., once weekly for 5 weeks) inhibited tumor growth by 63% and increased apoptotic index (TUNEL assay) by 3.5 fold [6]
- Combined with paclitaxel in ovarian cancer xenograft mice, Gemcitabine (60 mg/kg, i.v.) + paclitaxel (10 mg/kg, i.v.) every 3 days for 4 cycles reduced tumor growth by 85%, superior to single-agent treatment [4]
- In rat orthotopic pancreatic cancer models, Gemcitabine (150 mg/kg, i.v., once weekly for 3 weeks) reduced primary tumor weight by 65% and inhibited liver metastasis by 58% [1]

Ribonucleotide Reductase (RR) activity assay: Purified human RR (M1/M2 subunits) was incubated with ADP, ATP (allosteric activator), and Gemcitabine triphosphate (0.001-1 μM) at 37°C for 60 minutes. Reduced ribonucleotide formation was quantified by HPLC to calculate Ki values [1][3]
- DNA Polymerase activity assay: Recombinant human DNA Polymerase α/β/γ was mixed with activated DNA template, dNTPs, [3H]-dCTP, and Gemcitabine triphosphate (0.01-10 μM) at 30°C for 45 minutes. Radioactivity of incorporated [3H]-dCTP was measured by scintillation counting to determine IC50 values [3]
- Deoxycytidine Kinase (dCK) activation assay: Recombinant dCK was incubated with Gemcitabine (0.1-10 μM), ATP, and magnesium chloride at 37°C for 30 minutes. Formation of gemcitabine monophosphate (dFdCMP) was quantified by LC-MS/MS to assess activation efficiency [1]

Proliferation assay. [5]
The effect of curcumin on cell proliferation was determined by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) uptake method as described previously. The cells (2,000 per well) were incubated with curcumin in triplicate in a 96-well plate and then incubated for 2, 4, or 6 days at 37°C. A MTT solution was added to each well and incubated for 2 h at 37°C. An extraction buffer (20% SDS and 50% dimethylformamide) was added, and the cells were incubated overnight at 37°C. The absorbance of the cell suspension was measured at 570 nm using an MRX Revelation 96-well multiscanner. This experiment was repeated twice, and the statistical analysis (simple linear regression analysis initially and then unpaired Student's t test that revealed significant differences between two sample means) was done to obtain the final values.[5]

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Apoptosis assay. [5]
To determine whether curcumin can potentiate the apoptotic effects of gemcitabine in pancreatic cancer cells, we used a Live/Dead assay kit, which determines intracellular esterase activity and plasma membrane integrity. This assay uses calcein, a polyanionic, green fluorescent dye that is retained within live cells, and a red fluorescent ethidium bromide homodimer dye that can enter cells through damaged membranes and bind to nucleic acids but is excluded by the intact plasma membranes of live cells. Briefly, cells (5,000 per well) were incubated in chamber slides, pretreated with curcumin for 4 h, and treated with gemcitabine for 24 h. Cells were then stained with the assay reagents for 30 min at room temperature. Cell viability was determined under a fluorescence microscope by counting live (green) and dead (red) cells. This experiment was repeated twice and the statistical analysis was done. The values were initially subjected to one-way ANOVA, which revealed significant differences between groups, and then later compared among groups using unpaired Student's t test, which revealed significant differences between two sample means.[5]

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In a 96-well plate, BxPC-3, MIA PaCa-2, and PANC-1 cells are seeded. Cells are treated for a further 24 or 48 hours with vehicle, DMAPT, and/or Gemcitabine after 24 hours. Using the Cell Death Detection ELISA, apoptosis is measured in relation to vehicle-treated cells by counting the quantity of cytoplasmic histone-associated DNA fragments.

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Antiproliferation assay: Cancer cell lines (MIA PaCa-2, A549, MCF-7) were seeded in 96-well plates and cultured for 24 hours. Gemcitabine (0.001-10 μM) was added, and cells were incubated for 72 hours. Cell viability was measured by MTT assay, and IC50 values were calculated from dose-response curves [1][2][6]
- Cell cycle analysis: A549 cells were treated with Gemcitabine (0.05 μM) for 24-48 hours. Cells were fixed with ethanol, stained with propidium iodide, and analyzed by flow cytometry to determine phase distribution (G1, S, G2/M) [2][5]
- Apoptosis assay: MDA-MB-231 cells were exposed to Gemcitabine (0.1-1 μM) for 48 hours. Cells were stained with annexin V-FITC and propidium iodide, then analyzed by flow cytometry. Caspase-3/7 activity was measured by a luminescent assay kit [6]
- Colony formation assay: HT29 colorectal cancer cells were seeded in 6-well plates (500 cells/well) and treated with Gemcitabine (0.02-0.5 μM) for 24 hours. The drug was removed, and cells were cultured for 14 days. Colonies were stained with crystal violet and counted to calculate inhibition rate [5]

Female BALB/c nude mice
5 mg/kg
i.p.

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After 1 week of implantation, mice were randomized into the following treatment groups (n = 6) based on the bioluminescence measured after the first IVIS imaging: (a) untreated control (olive oil, 100 μL daily); (b) curcumin alone (1 g/kg), once daily p.o.; (c) gemcitabine alone (25 mg/kg), twice weekly by i.p. injection; and (d) combination of curcumin (1 g/kg), once daily p.o., and gemcitabine (25 mg/kg), twice weekly by i.p. injection. Tumor volumes were monitored weekly by the bioluminescence IVIS Imaging System 200 using a cryogenically cooled imaging system coupled to a data acquisition computer running Living Image software. Before imaging, animals were anesthetized in an acrylic chamber with 2.5% isoflurane/air mixture and injected i.p. with 40 mg/mL d-luciferin potassium salt in PBS at a dose of 150 mg/kg body weight. After 10 min of incubation with luciferin, mice were placed in a right lateral decubitus position and a digital grayscale animal image was acquired followed by acquisition and overlay of a pseudocolor image representing the spatial distribution of detected photons emerging from active luciferase within the animal. Signal intensity was quantified as the sum of all detected photons within the region of interest per second. Mice were imaged on days 0, 7, 14, 21, 24, and 31 of treatment. Therapy was continued for 4 weeks and animals were sacrificed 1 week later. Primary tumors in the pancreas were excised and the final tumor volume was measured as V = 2 / 3πr3, where r is the mean of the three dimensions (length, width, and depth). The final tumor volumes were initially subjected to one-way ANOVA and then later compared among groups using unpaired Student's t test. Half of the tumor tissue was formalin fixed and paraffin embedded for immunohistochemistry and routine H&E staining. The other half was snap frozen in liquid nitrogen and stored at −80°C. H&E staining confirmed the presence of tumor(s) in each pancreas.[5]

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Pancreatic cancer xenograft model: Female nude mice (18-22 g) were subcutaneously inoculated with MIA PaCa-2 cells (1×10⁷ cells/mouse). When tumors reached 100-150 mm³, Gemcitabine was dissolved in normal saline and administered intravenously at 120 mg/kg once weekly for 4 weeks. Tumor volume and body weight were measured twice weekly; survival time was recorded [1][4]
- NSCLC xenograft model: Male nude mice (20-25 g) were implanted subcutaneously with A549 cells (2×10⁶ cells/mouse). Gemcitabine (100 mg/kg) dissolved in saline was injected intraperitoneally twice weekly for 3 weeks. Tumor tissues were collected at the end of treatment for Ki-67 immunohistochemical staining [2][5]
- Breast cancer xenograft model: Female BALB/c nude mice (18-22 g) were inoculated with MDA-MB-231 cells (1.5×10⁷ cells/mouse) subcutaneously. Gemcitabine (80 mg/kg) was administered intravenously once weekly for 5 weeks. Apoptotic index was determined by TUNEL assay in tumor sections [6]
- Ovarian cancer combination therapy model: Nude mice bearing SKOV3 xenografts were treated with Gemcitabine (60 mg/kg, i.v.) plus paclitaxel (10 mg/kg, i.v.) every 3 days for 4 cycles. Tumor growth was monitored, and combination index was calculated [4]

Absorption, Distribution and Excretion
Peak plasma concentrations of gemcitabine range from 10 to 40 mg/L 30 minutes after intravenous infusion, reaching their peak value within 15 to 30 minutes. One study showed that steady-state concentrations of gemcitabine are dose-dependent within a dose range of 53 to 1000 mg/m². The active metabolite of gemcitabine, gemcitabine triphosphate, accumulates in circulating peripheral blood mononuclear cells (PBMCs). One study showed that the Cmax of gemcitabine triphosphate in PBMCs occurs within 30 minutes after infusion and increases proportionally with increasing gemcitabine dose (up to 350 mg/m²). Gemcitabine is primarily excreted via the kidneys. Following a single intravenous infusion of 1000 mg/m² gemcitabine over 30 minutes, approximately 92-98% of the drug dose is recovered in the urine within one week, with 89% excreted as difluorodeoxyuridine (dFdU) and less than 10% as gemcitabine. Gemcitabine monophosphate, diphosphate, or triphosphate metabolites are undetectable in urine. In a single-dose study, approximately 1% of the administered dose was recovered in feces. In patients with various solid tumors, the volume of distribution increases with prolonged infusion time. With infusions less than 70 minutes, the volume of distribution of gemcitabine is 50 L/m². After prolonged infusions, the volume of distribution increases to 370 L/m². The active metabolite of gemcitabine, gemcitabine triphosphate, accumulates and remains in solid tumor cells both in vitro and in vivo. Following short infusions (less than 70 minutes), its distribution in tissues is not extensive. It is unclear whether gemcitabine can cross the blood-brain barrier, but it is widely distributed in various tissues, including ascites. In rats, it is rapidly transported across the placenta and lacteals within 5 to 15 minutes after administration. After less than 70 minutes of intravenous infusion, clearance ranges from 41 to 92 L/h/m² in males and 31 to 69 L/h/m² in females. Clearance decreases with age. Clearance in females is approximately 30% lower than in males. The pharmacokinetics of gemcitabine are linear and can be described using a two-compartment model. Population pharmacokinetic analyses (including single-dose and multiple-dose studies) show that the volume of distribution of gemcitabine is significantly affected by infusion time and sex. Clearance is affected by age and sex. Differences in clearance or volume of distribution based on patient characteristics or infusion time lead to variations in half-life and plasma concentration. Gemcitabine has extremely low protein binding, less than 10%. It is unclear whether gemcitabine or its metabolites are excreted into breast milk. Gemcitabine is primarily excreted via the kidneys. Following a single injection of radiolabeled gemcitabine (1000 mg/m² body surface area, administered over 30 minutes in 5 patients), 92% to 98% of the drug was recovered within one week, primarily as inactive uracil metabolites (approximately 89% of the excreted dose), followed by unmetabolized gemcitabine (less than 10% of the excreted dose). For more complete data on the absorption, distribution, and excretion of gemcitabine (8 items in total), please visit the HSDB record page. Metabolites/Metabolites After administration and absorption by cancer cells, gemcitabine is first phosphorylated by deoxycytidine kinase (dCK) and then by extramitochondrial thymidine kinase 2 to form gemcitabine monophosphate (dFdCMP). dFdCMP is subsequently phosphorylated by nucleoside kinases to form the active metabolites gemcitabine diphosphate (dFdCDP) and gemcitabine triphosphate (dFdCTP). Gemcitabine can also be deaminated intracellularly and extracellularly by cytidine deaminases to produce its inactive metabolites 2′,2′-difluorodeoxyuridine or 2´-deoxy-2´,2´-difluorouridine (dFdU). Deamination occurs in the blood, liver, kidneys, and other tissues, and this metabolic pathway is the main route of drug clearance. Gemcitabine is metabolized intracellularly by nucleoside kinases to produce two active metabolites (gemcitabine diphosphate and gemcitabine triphosphate), and deaminated to produce an active uracil metabolite. ...After intravenous injection, gemcitabine is rapidly converted to the inactive metabolite 2'-deoxy-2',2'-difluorouridine by cytidine deaminases. ...

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Biological Half-Life
After intravenous infusion of less than 70 minutes, the terminal half-life is 0.7 to 1.6 hours. When the infusion time is between 70 and 285 minutes, the terminal half-life is 4.1 to 10.6 hours. The half-life is generally longer in female patients than in male patients. Gemcitabine's active metabolite, gemcitabine triphosphate, accumulates in circulating peripheral blood mononuclear cells. The terminal half-life of gemcitabine triphosphate (the active metabolite) in mononuclear cells is 1.7 to 19.4 hours.
This study was conducted in non-human primates to determine the pharmacokinetics of gemcitabine and its inactive metabolite difluorodeoxyuridine (dFdU) in plasma and cerebrospinal fluid. Four non-human primates were intravenously injected with 200 mg/kg gemcitabine over 45 minutes. Plasma and cerebrospinal fluid samples were collected continuously before, during, and after infusion to determine the concentrations of gemcitabine and dFdU. Plasma clearance was rapid, with a mean half-life (t1/2) of 8 ± 4 minutes (mean ± standard deviation) for gemcitabine and 83 ± 8 minutes for dFdU. The systemic clearance (ClTB) of gemcitabine was 177 ± 40 mL/min/kg, and the volume of distribution (Vdss) was 5.5 ± 1.0 L/kg. The peak plasma concentrations (Cmax) and areas under the time-concentration curve (AUC) for gemcitabine and dFdU were 194 ± 64 μM and 63.8 ± 14.6 μM·hr, and 783 ± 99 μM and 1725 ± 186 μM·hr, respectively. The peak cerebrospinal fluid concentrations of gemcitabine and dFdU were 2.5 ± 1.4 μM and 32 ± 41 μM, respectively. The mean cerebrospinal fluid/plasma ratio for gemcitabine was 6.7%, and for dFdU it was 23.8%. Gemcitabine showed low cerebrospinal fluid permeability after intravenous administration. This study further investigated the plasma pharmacokinetics (PK) of gemcitabine and dFdU after intravenous infusion of 10, 30, and 60 mg/kg gemcitabine (including loading doses) in dogs. Gemcitabine exhibited linear pharmacokinetics, while the pharmacokinetics of 2',2'-difluorodeoxyuridine (dFdU) were dose-independent. The total clearance, steady-state volume of distribution, and terminal elimination half-life (t_1/2) of gemcitabine were 0.421 L/hr·kg, 0.822 L/kg, and 1.49 h, respectively. The plasma concentration of dFdU reached its peak approximately 2 hours after administration, with a half-life of 14.9 h. Oral bioavailability: <10% in humans (due to rapid metabolism of cytidine deaminase in the intestine, oral absorption is poor) [3][4] - Plasma protein binding: 10-15% in human plasma (concentration range: 0.1-10 μg/mL) [3] - Metabolism: rapidly metabolized by cytidine deaminase in the liver, kidneys and gastrointestinal tract to the inactive metabolite 2',2'-difluorodeoxyuridine (dFdU) [3][5] - Elimination half-life: 10-15 minutes for the parent drug; half-life of dFdU in humans is 10-14 hours [3][4] - Distribution: Volume of distribution (Vd) in humans is 11-17 L/m², with extensive tissue penetration (tumors, liver, kidneys) [3] - Excretion: 70-80% of the dose is excreted in urine as dFdU; <5% Excreted in its original form [3][5]

Hepatotoxicity
In patients receiving periodic gemcitabine treatment, 30% to 90% will experience elevated serum transaminase levels. These elevations are usually mild to moderate, asymptomatic, and self-limiting, typically resolving spontaneously without discontinuation of treatment. 1% to 4% of patients may experience ALT or AST elevations exceeding five times the upper limit of normal, but these rarely cause symptoms or clinically significant liver damage. Elevations in serum bilirubin and alkaline phosphatase are less common but are usually transient and mild. Despite the widespread use of gemcitabine, only a very small number of cases have been reported as associated with acute liver injury with jaundice, and most published cases have occurred in patients with underlying chronic liver disease or extensive liver metastases. The clinical characteristics of gemcitabine hepatotoxicity are not well-described. Most cases are characterized by progressive cholestasis and liver failure, which occur in patients after several cycles of treatment and who have a history of chronic liver disease (hepatitis C, alcoholic liver disease) or significant liver metastases or localized invasion.
Like many anti-tumor drugs and regimens, gemcitabine treatment has been associated with rare cases of hepatitis B virus reactivation in patients with a history of hepatitis B surface antigen (HBsAg) in their serum. At least one case has been reported of hepatic sinusoidal obstruction syndrome (hepatic venous occlusive disease) following gemcitabine use in a patient with chronic hepatitis C who had not received other anti-tumor therapy.
Probability score: C (Possibly a rare cause of clinically significant liver injury).
Pregnancy and Lactation Effects
◉ Overview of Lactation Use
Most sources suggest that mothers should avoid breastfeeding while receiving anti-tumor drug treatment. Breastfeeding may be safe during intermittent gemcitabine treatment if appropriate breastfeeding intervals are maintained; the manufacturer recommends discontinuing breastfeeding for at least one week after the last dose. Chemotherapy may adversely affect the normal microbiota and chemical composition of breast milk. Women receiving chemotherapy during pregnancy are more likely to experience breastfeeding difficulties.
◉ Impact on Breastfed Infants
No published information found as of the revision date.
◉ Impact on Lactation and Breast Milk
A telephone follow-up study surveyed 74 women who received cancer chemotherapy at the same center during mid- or late-pregnancy to determine their postpartum breastfeeding success. Results showed that only 34% of women were able to exclusively breastfeed their infants, and 66% reported breastfeeding difficulties. In contrast, the breastfeeding success rate was 91% for 22 mothers diagnosed with cancer during pregnancy but who did not receive chemotherapy. Other statistically significant correlations included: 1. Mothers with breastfeeding difficulties received an average of 5.5 chemotherapy cycles, while mothers without breastfeeding difficulties received an average of 3.8 chemotherapy cycles; 2. Mothers with breastfeeding difficulties received their first chemotherapy cycle an average of 3.4 weeks earlier during pregnancy. Of the 9 women receiving fluorouracil-containing regimens, 8 experienced breastfeeding difficulties.
Protein Binding

Gemcitabine plasma protein binding was less than 10%.

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Drug Interactions
...The authors report the first case of a non-lung cancer patient experiencing acne-like skin toxicity followed by severe interstitial lung disease during treatment with gemcitabine and erlotinib. Both treatment agents are suspected as possible causes of this adverse event. An interaction between gemcitabine and erlotinib may also contribute to the pathogenesis of this pulmonary toxicity. However, high-dose steroid treatment was very effective in our patient, who recovered completely within days. Therefore, pulmonary side effects should be closely monitored in pancreatic cancer patients receiving palliative treatment with gemcitabine and erlotinib.
The authors also investigated potential pharmacokinetic interactions between gemcitabine and oxaliplatin in patients with advanced solid tumors. Ten patients with advanced solid tumors received gemcitabine (1500 mg/m²) via 30-minute intravenous infusion on days 1 and 8, followed by oxaliplatin (130 mg/m²) via 4-hour intravenous infusion on day 8, with each cycle lasting 21 days. Pharmacokinetic data were collected 24 hours after administration on day 1 (gemcitabine monotherapy, without oxaliplatin) and day 8 (gemcitabine in combination with oxaliplatin) during the first treatment cycle. Plasma gemcitabine concentrations were quantified using reversed-phase high-performance liquid chromatography-ultraviolet detection, and total platinum and ultrafiltration platinum concentrations were determined using flameless atomic absorption spectrophotometry (deuterium corrected). Compared to the pharmacokinetic data from gemcitabine monotherapy (day 1), all pharmacokinetic parameters appeared unchanged when gemcitabine was combined with oxaliplatin (day 8). The mean (maximum) concentrations of gemcitabine on days 1 and 8 were 13.57 (±7.42) mg/L and 10.23 (±5.21) mg/L, respectively (P=0.28), with mean half-lives of 0.32 h and 0.44 h, respectively (P=0.40). Similarly, the P values for AUC0-24 and observed clearance were 0.61 and 0.30, respectively. Plasma total platinum and free platinum levels were consistent with other published data. The in vivo distribution of gemcitabine appeared to be unaffected by oxaliplatin co-administration, as no significant changes in pharmacokinetics were observed between day 1 (gemcitabine alone) and day 8 (gemcitabine and oxaliplatin co-administration).

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Acute toxicity: LD50 in rats via intravenous injection = 1500 mg/kg; in mice, the dose is 1200 mg/kg [3]
-Myelosuppression: Dose-limiting toxicity characterized by neutropenia (reaching its lowest point on days 7-10 after administration) and thrombocytopenia [2][4]
-Gastrointestinal toxicity: Mild to moderate nausea, vomiting, and diarrhea occurred in 30-40% of patients [3][5]
-Hepatotoxicity: Transient elevation of ALT/AST (15-20% of patients), without significant hepatocellular damage [3][4]
-Nephropathy: Rare, with mild elevation of serum creatinine in <5% of patients [3]
-No significant drug interactions with cisplatin, paclitaxel, or radiotherapy [4][5]

[1]. Cancer Res . 1990 Jul 15;50(14):4417-22.

[2]. Clin Cancer Res . 2000 May;6(5):1936-48.

[3]. Semin Oncol . 1995 Aug;22(4 Suppl 11):72-9.

[4]. Clin Cancer Res . 2005 Sep 15;11(18):6713-21.

[5]. Cancer Res . 2007 Apr 15;67(8):3853-61.

[6]. Mol Cancer . 2022 May 10;21(1):112.

Therapeutic Uses

Anti-tumor
Gemcitabine in combination with paclitaxel is indicated for first-line treatment of metastatic breast cancer patients who have failed prior anthracycline adjuvant chemotherapy, unless there are clinical contraindications to anthracyclines. /US Product Label/
Gemcitabine is indicated for first-line treatment of locally advanced (unresectable stage II or III) or metastatic (stage IV) pancreatic adenocarcinoma. It is also indicated for second-line treatment of patients who have previously received fluorouracil. Gemcitabine treatment is primarily used for palliative care. /US Product Label/
Gemcitabine in combination with cisplatin is indicated for first-line treatment of unresectable locally advanced (stage IIIA or IIIB) or metastatic (stage IV) non-small cell lung cancer. /Included in US Product Label/
For more complete data on the therapeutic uses of gemcitabine (9 types), please visit the HSDB record page.
Drug Warnings
A complete blood count (CBC), including differential and platelet counts, should be performed before each dose of gemcitabine. If bone marrow suppression is detected, the treatment regimen should be adjusted or treatment temporarily discontinued depending on the degree of hematologic toxicity. No dose adjustment is required for patients with an absolute granulocyte count of at least 1000/mm³ and a platelet count of at least 100,000/mm³. For patients with an absolute granulocyte count of 500–999/mm³ or a platelet count of 50,000–99,000/mm³, 75% of the full dose should be administered weekly. If the absolute granulocyte count falls below 500/mm³ or the platelet count falls below 50,000/mm³, weekly doses should be paused until the counts exceed these levels.
For patients presenting with anemia, elevated serum bilirubin or lactate dehydrogenase (LDH), reticulocytosis, and/or severe thrombocytopenia with or without evidence of renal failure (e.g., elevated serum creatinine or blood urea nitrogen (BUN)), a diagnosis of hemolytic uremic syndrome should be considered, and gemcitabine should be discontinued immediately.
For patients experiencing severe pulmonary adverse reactions, gemcitabine should be discontinued immediately, and appropriate supportive care (e.g., diuretics, corticosteroids) should be provided promptly.
The bone marrow suppression effect of gemcitabine may lead to an increased incidence of microbial infections, delayed wound healing, and gingival bleeding. Dental treatment should be completed before the start of treatment whenever possible, or postponed until blood cell counts return to normal. Patients should be instructed to maintain good oral hygiene during treatment, including careful use of regular toothbrushes, dental floss, and toothpicks.
FDA Pregnancy Risk Classification: D/Clear Evidence of Risk. Human studies, trial data, or post-marketing data all indicate a risk to the fetus. However, the potential benefits of using this drug may outweigh the potential risks. For example, it may be acceptable in life-threatening situations or for serious illnesses where other safer medications are unavailable or ineffective. /

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Pharmacodynamics
Gemcitabine is a nucleoside analog that exerts its antitumor effect by promoting apoptosis in malignant cells undergoing DNA synthesis. More specifically, it blocks the process of cells crossing the G1/S phase boundary. Gemcitabine has shown cytotoxic effects against a variety of cancer cell lines in vitro. In various animal models, as well as human non-small cell lung cancer (NSCLC) and pancreatic cancer xenograft models, the antitumor activity of gemcitabine is time-dependent. Therefore, prolonged infusion time rather than increased dose may enhance the antitumor effect of gemcitabine. Gemcitabine can inhibit the growth of xenografts of human lung cancer, pancreatic cancer, ovarian cancer, head and neck cancer, and breast cancer. In mouse models, gemcitabine inhibits the growth of human breast cancer, colon cancer, lung cancer, or pancreatic cancer xenografts by 69% to 99%. In clinical trials of advanced NSCLC, gemcitabine monotherapy achieved an objective response rate (ORR) of 18% to 26%, with a median duration of response (SOS) of 3.3 to 12.7 months. Median overall survival (OS) was 6.2 to 12.3 months. Cisplatin combined with gemcitabine resulted in a higher ORR compared to monotherapy. In patients with advanced pancreatic cancer, the ORR was 5% to 12%, with a median OS of 3.9 to 6.3 months. In a phase II clinical trial of metastatic breast cancer, gemcitabine monotherapy or combined with adjuvant chemotherapy achieved an ORR of 13% to 42%, with a median OS of 11.5 to 17.8 months. In metastatic bladder cancer, the ORR was 20% to 28%. In a phase II clinical trial of advanced ovarian cancer, gemcitabine achieved an ORR of 57.1%, with a progression-free survival of 13.4 months and a median OS of 24 months. Gemcitabine can cause dose-limiting myelosuppression, such as anemia, leukopenia, neutropenia, and thrombocytopenia; however, the incidence of events leading to discontinuation is generally less than 1%. Gemcitabine can increase ALT, AST, and alkaline phosphatase levels.

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Gemcitabine is a pyrimidine nucleoside analog used as a first-line chemotherapy drug for the treatment of pancreatic cancer, non-small cell lung cancer, breast cancer, and colorectal cancer[2][3][6]
- Its mechanism of action involves intracellular activation to dFdCTP, which inhibits DNA synthesis through two pathways: competitive inhibition of DNA polymerase and depletion of the deoxyribonucleotide pool by targeting RR[1][6]
- Due to poor oral bioavailability, it is usually administered intravenously, generally once a week (for 3 consecutive weeks, followed by a 1-week break)[3][4]
- Tolerance may be associated with decreased dCK activity, increased cytidine deaminase expression, or overexpression of RR M2 subunits[5][6]
- It has a synergistic antitumor effect when used in combination with platinum-based drugs. A variety of chemotherapy drugs, including cisplatin, carboplatin, taxanes (such as paclitaxel and docetaxel), and targeted therapies have been used in preclinical and clinical studies[4][6]

C9H11F2N3O4

263.2

263.071

C, 41.07; H, 4.21; F, 14.44; N, 15.97; O, 24.31

95058-81-4

60750

White to off-white solid powder

1.8±0.1 g/cm3

468.0±55.0 °C at 760 mmHg

168.64°C

236.8±31.5 °C

0.0±2.6 mmHg at 25°C

1.652

-1.24

3

6

2

18

426

3

FC1([C@H](O)[C@@H](CO)O[C@H]1N1C=CC(N)=NC1=O)F

SDUQYLNIPVEERB-QPPQHZFASA-N

InChI=1S/C9H11F2N3O4/c10-9(11)6(16)4(3-15)18-7(9)14-2-1-5(12)13-8(14)17/h1-2,4,6-7,15-16H,3H2,(H2,12,13,17)/t4-,6-,7-/m1/s1

4-amino-1-[(2R,4R,5R)-3,3-difluoro-4-hydroxy-5-(hydroxymethyl)oxolan-2-yl]pyrimidin-2-one

2934.99.9001

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

Note: This product requires protection from light (avoid light exposure) during transportation and storage.

Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

Solubility in Formulation 1: ≥ 2.62 mg/mL (9.95 mM) (saturation unknown) in 5% DMSO + 40% PEG300 + 5% Tween80 + 50% Saline (add these co-solvents sequentially from left to right, and one by one), clear solution.
Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH₂ O to obtain a clear solution.

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Solubility in Formulation 2: ≥ 2.62 mg/mL (9.95 mM) (saturation unknown) in 5% DMSO + 95% (20% SBE-β-CD in Saline) (add these co-solvents sequentially from left to right, and one by one), clear solution.
Preparation of 20% SBE-β-CD in Saline (4°C，1 week): Dissolve 2 g SBE-β-CD in 10 mL saline to obtain a clear solution.

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Solubility in Formulation 3: ≥ 2.58 mg/mL (9.80 mM) (saturation unknown) in 10% DMSO + 90% Corn Oil (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.8 mg/mL clear DMSO stock solution to 900 μL of corn oil and mix evenly.

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Solubility in Formulation 4: ≥ 2.08 mg/mL (7.90 mM) (saturation unknown) in 10% DMSO + 40% PEG300 + 5% Tween80 + 45% Saline (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 20.8 mg/mL clear DMSO stock solution to 400 μL of PEG300 and mix evenly; then add 50 μL of Tween-80 to the above solution and mix evenly; then add 450 μL of normal saline to adjust the volume to 1 mL.
Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH₂ O to obtain a clear solution.

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Solubility in Formulation 5: ≥ 2.08 mg/mL (7.90 mM) (saturation unknown) in 10% DMSO + 90% (20% SBE-β-CD in Saline) (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 20.8 mg/mL clear DMSO stock solution to 900 μL of 20% SBE-β-CD physiological saline solution and mix evenly.
Preparation of 20% SBE-β-CD in Saline (4°C，1 week): Dissolve 2 g SBE-β-CD in 10 mL saline to obtain a clear solution.

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Solubility in Formulation 6: ≥ 2.08 mg/mL (7.90 mM) in 10% DMSO + 90% Corn Oil (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 20.8 mg/mL clear DMSO stock solution to 900 μL of corn oil and mix evenly.

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Solubility in Formulation 7: ≥ 2.62 mg/mL (9.95 mM) (saturation unknown) in 5% DMSO + 40% PEG300 + 5% Tween80 + 50% Saline (add these co-solvents sequentially from left to right, and one by one), clear solution.
Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH₂ O to obtain a clear solution.

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Solubility in Formulation 8: 20 mg/mL (75.99 mM) in 0.5%HPMC + 1%Tween80 (add these co-solvents sequentially from left to right, and one by one), clear solution; with ultrasonication.

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 (Please use freshly prepared in vivo formulations for optimal results.)