Tocimab IV Infusion 200 mg/10 ml 200 mg/10 ml Uses, Dosage, Side Effects & Price - টোকিমাব আইভি ইনফিউশন

Name: Tocimab IV Infusion 200 mg/10 ml
Brand: Tocimab
SKU: tocimab-iv-infusion-200-mg-10-ml
Price: 1020000 BDT
Availability: OnlineOnly

Brand Name	Tocimab
Type	IV Infusion
Weight	200 mg/10 ml
Generic	Tocilizumab
Manufacturer	Healthcare Pharmaceuticals Ltd.
Price	10 ml vial: ৳ 20,000.00

Brand Name

Tocimab

Type

IV Infusion

Weight

200 mg/10 ml

Generic

Tocilizumab

Manufacturer

Healthcare Pharmaceuticals Ltd.

Price

10 ml vial: ৳ 20,000.00

About Tocimab

Tocimab IV Infusion (Healthcare Pharmaceuticals Ltd.) is a brand medicine containing the generic Tocilizumab . Current listed price in Bangladesh: 10 ml vial: ৳ 20,000.00.

Introduction

Tocimab IV Infusion 200 mg/10 ml is a recombinant humanized monoclonal antibody IL-6 receptor inhibitor used to treat inflammatory and autoimmune conditions. It was first described in the literature in 2003 when Chugai, a subsidiary of Roche began developing IL-6 inhibiting monoclonal antibodies. It is currently being investigated to treat severely ill patients with COVID-19.

Uses

Tocimab IV Infusion 200 mg/10 ml is an interleukin-6 (IL-6) receptor antagonist used to treat Cytokine Release Syndrome (CRS), Systemic Juvenile Idiopathic Arthritis (sJIA), Giant Cell Arteritis (GCA), and Rheumatoid Arthritis (RA).

Tocimab IV Infusion 200 mg/10 ml is indicated to treat moderate to severe rheumatoid arthritis, giant cell arteritis, polyarticular juvenile idiopathic arthritis, systemic juvenile idiopathic arthritis, and cytokine release syndrome.

Associated Conditions

Cytokine Release Syndrome caused by CAR-T Cell Therapy
Giant Cell Arteritis (GCA)
Moderate to Severe Rheumatoid Arthritis
Polyarticular Juvenile Idiopathic Arthritis
Systemic Juvenile Idiopathic Arthritis (SJIA)

Pharmacodynamics

Tocimab IV Infusion 200 mg/10 ml is an IL-6 inhibiting monoclonal antibody used to treat autoimmune and inflammatory conditions. Tocimab IV Infusion 200 mg/10 ml has a long duration of action as it is generally given every 4 weeks and has a wide therapeutic index. Patients should be counselled regarding the risk of infections, GI perforation, and hepatotoxicity.

Mechanism of Action

Interleukin 6 (IL-6) is a pro-inflammatory cytokine produced by cells including T-cells, B-cells, lymphocytes, monocytes, fibroblasts. IL-6 rapidly induces C-reactive protein, serum amyloid A, fibrinogen, haptoglobin, and α-1-antichymotrypsin while inhibiting production of fibronectin, albumin, and transferrin. IL-6 also induces antibody production, induces cytotoxic T-cell differentiation, and inhibits regulatory T-cell differentiation. Tocimab IV Infusion 200 mg/10 ml binds soluble and membrane bound IL-6 receptors, preventing IL-6 mediated inflammation.

Absorption

A 162mg subcutaneous dose given weekly has a C_max of 51.3±23.2µg/mL and an AUC of 8254±3833µg*h/mL. A 162mg subcutaneous dose given every 2 weeks has a C_max of 13±8.3µg/mL and an AUC of 3460±2530µg*h/mL. A 162mg subcutaneous dose given every 4 weeks has a C_max of 154±42µg/mL and an AUC of 39216±14304µg*h/mL.

Volume of Distribution

In rheumatoid arthritis patients, the central volume of distribution is 3.5L, the peripheral volume of distribution is 2.9L, and the volume of distribution at steady state is 6.4L. In giant cell arteritis patients, the central volume of distribution is 4.09L, the peripheral volume of distribution if 3.37L, and the volume of distribution at steady state is 7.46L. In pediatric patients with polyarticular juvenile arthritis, the central volume of distribution is 1.98L, the peripheral volume of distribution is 2.1L, and the volume of distribution at steady state is 4.08L. In pediatric patients with systemic juvenile idiopathic arthritis, the central volume of distribution is 1.87L, the peripheral volume of distribution is 2.14L, and the volume of distribution at steady state is 4.01L.

Protein Binding

Data regarding the serum protein binding of tocilizumab is not readily available.

Route of Elimination

Data regarding the exact route of elimination of monoclonal antibodies is not readily available.

Half Life

The half life of tocilizumab is concentration dependent. The terminal half life in rheumatoid arthritis patients is 21.5 days. The absorption half life in rheumatoid arthritis and giant cell arteritis patients was 4 days, and in polyarticular juvenile idiopathic arthritis patients and systemic juvenile idiopathic arthritis patients was 2 days.

Clearance

The linear clearance in rheumatoid arthritis patients is 12.5mL/h, in giant cell arteritis patients is 6.7mL/h, in polyarticular juvenile idiopathic arthritis patients is 5.8mL/h, and in systemic juvenile idiopathic arthritis is 5.7mL/h. Clearance is dose dependent and changes from non linear at low doses to linear at higher doses.

Toxicity

Data regarding overdoses of tocilizumab are not readily available. Patients experiencing an overdose may develop neutropenia. In case of overdose, monitor patients for signs of adverse reactions and provide symptomatic and supportive treatment.

Food Interactions

No interactions found.

Dosage

Interruption of dosing may be needed for management of dose-related laboratory abnormalities including elevated liver enzymes, neutropenia, and thrombocytopenia.

Rheumatoid Arthritis: Tocimab IV Infusion 200 mg/10 ml may be used as monotherapy or concomitantly with methotrexate or other non-biologic DMARDs as an intravenous infusion.

Recommended Intravenous Dosage Regimen:

The recommended dosage of Tocimab IV Infusion 200 mg/10 ml for adult patients given as a 60-minute single intravenous drip infusion is 4 mg per kg of body weight every 4 weeks followed by an increase to 8 mg per kg of body weight every 4 weeks based on clinical response.
Reduction of dose from 8 mg per kg of body weight to 4 mg per kg of body weight is recommended for management of certain dose-related laboratory changes including elevated liver enzymes, neutropenia, and thrombocytopenia
Doses exceeding 800 mg per infusion are not recommended in RA patients

Polyarticular Juvenile Idiopathic Arthritis: Tocimab IV Infusion 200 mg/10 ml may be used as an intravenous infusion or as a
subcutaneous injection alone or in combination with methotrexate. Do not change dose based solely on a single body weight measurement, as weight may fluctuate.

Recommended Intravenous Dosage Regimen: The recommended dosage of Tocimab IV Infusion 200 mg/10 ml for PJIA patients given once every 4 weeks as a 60-minute single intravenous drip infusion is:

Patients less than 30 kg weight: 10 mg per kg of body weight
Patients at or above 30 kg weight: 8 mg per kg of body weight

Systemic Juvenile Idiopathic Arthritis: Tocimab IV Infusion 200 mg/10 ml may be used as an intravenous infusion or as a subcutaneous injection alone or in combination with methotrexate. Do not change a dose based solely on a single body weight measurement, as weight may fluctuate.

Recommended Intravenous Dosage Regimen: The recommended dose of Tocimab IV Infusion 200 mg/10 ml for SJIA patients given
once every 2 weeks as a 60-minute single intravenous drip infusion is:

Patients less than 30 kg weight: 12 mg per kg of body weight
Patients at or above 30 kg weight: 8 mg per kg of body weight

Coronavirus Disease 2019: The recommended dosage of Tocimab IV Infusion 200 mg/10 ml is a single 60-minute
intravenous infusion as follows:

Patients less than 30 kg weight: 12 mg per kg of body weight
Patients at or above 30 kg weight: 8 mg per kg of body weight

If clinical signs or symptoms worsen or do not improve after the first dose, one additional infusion of Tocimab IV Infusion 200 mg/10 ml may be administered at least 8 hours after the initial infusion. Maximum dosage in COVID-19 patients is 800 mg per infusion.

Cytokine Release Syndrome: Use only the intravenous route for treatment of CRS. The recommended dose of Tocimab IV Infusion 200 mg/10 ml for treatment of CRS given as a 60-minute intravenous infusion is:

Recommended Intravenous CRS Dosage

Patients less than 30 kg weight: 12 mg per kg of body weight Alone or in combination with corticosteroids.
Patients at or above 30 kg weight: 8 mg per kg of body weight Alone or in combination with corticosteroids.

If no clinical improvement in the signs and symptoms of CRS occurs after the first dose, up to 3 additional doses of Tocimab IV Infusion 200 mg/10 ml may be administered. The interval between consecutive doses should be at least 8 hours. Doses exceeding 800 mg per infusion are not recommended in CRS patients.

Giant Cell Arteritis:

The recommended dosage of Tocimab IV Infusion 200 mg/10 ml for adult patients given as a 60-minute single intravenous drip infusion is 6 mg per kg of body weight every 4 weeks in combination with a tapering course of glucocorticoids.
Tocimab IV Infusion 200 mg/10 ml can be used alone following discontinuation of glucocorticoids
Doses exceeding 600 mg per infusion are not recommended in GCA patients

Systemic Sclerosis-Associated Interstitial Lung Disease:

The recommended dose of Tocimab IV Infusion 200 mg/10 ml for adult patients with SSc-ILD is 162 mg given once every week as a subcutaneous injection.
Intravenous administration is not approved for SSc-ILD

Administration of Intravenous Formulation:

For adults with RA, GCA, CRS, PJIA and SJIA patients at or above 30 kg, dilute to 100 mL in 0.9% or 0.45% Sodium Chloride Injection, USP for intravenous infusion using aseptic technique
For PJIA, SJIA and CRS patients less than 30 kg, dilute to 50 mL in 0.9% or 0.45% Sodium Chloride Injection, USP for intravenous infusion using aseptic technique
Administer as a single intravenous drip infusion over 1 hour; do not administer as bolus or push.

Frequently Asked Questions About Tocimab IV Infusion 200 mg/10 ml

1. What is Tocimab IV Infusion 200 mg/10 ml?

Tocimab IV Infusion 200 mg/10 ml is a monoclonal antibody that is used to treat various inflammatory conditions, including rheumatoid arthritis, giant cell arteritis, and cytokine release syndrome. It works by blocking the interleukin-6 (IL-6) receptor, which plays a role in inflammation.

2. How does Tocimab IV Infusion 200 mg/10 ml work?

Tocimab IV Infusion 200 mg/10 ml works by binding to and inhibiting the IL-6 receptor, preventing IL-6 from exerting its inflammatory effects. IL-6 is a cytokine involved in the body's immune response and inflammation, and by blocking this receptor, Tocimab IV Infusion 200 mg/10 ml helps reduce inflammation and tissue damage.

3. What are the main uses of Tocimab IV Infusion 200 mg/10 ml?

Tocimab IV Infusion 200 mg/10 ml is primarily used to treat conditions such as rheumatoid arthritis, giant cell arteritis, systemic juvenile idiopathic arthritis, cytokine release syndrome (CRS), and severe COVID-19-related inflammation.

4. Is Tocimab IV Infusion 200 mg/10 ml used for rheumatoid arthritis?

Yes, Tocimab IV Infusion 200 mg/10 ml is commonly used for the treatment of moderate to severe rheumatoid arthritis in adults who have not responded adequately to other disease-modifying antirheumatic drugs (DMARDs).

5. Can Tocimab IV Infusion 200 mg/10 ml be used for COVID-19?

Tocimab IV Infusion 200 mg/10 ml has been used to treat severe COVID-19 in hospitalized patients, particularly those with high levels of inflammation (e.g., elevated C-reactive protein levels). It helps reduce the inflammatory response associated with severe COVID-19 infections.

6. How is Tocimab IV Infusion 200 mg/10 ml administered?

Tocimab IV Infusion 200 mg/10 ml is typically administered through an intravenous (IV) infusion in a healthcare setting. It can also be given as a subcutaneous injection for certain conditions, such as rheumatoid arthritis.

7. What are the potential side effects of Tocimab IV Infusion 200 mg/10 ml?

Common side effects of Tocimab IV Infusion 200 mg/10 ml include headache, high blood pressure, liver enzyme elevations, infections, and gastrointestinal issues. Serious side effects can include severe infections, gastrointestinal perforation, and liver damage.

8. Can Tocimab IV Infusion 200 mg/10 ml cause an allergic reaction?

Yes, some individuals may experience allergic reactions to Tocimab IV Infusion 200 mg/10 ml. Symptoms may include rash, itching, difficulty breathing, and swelling of the face or throat. Immediate medical attention is required for severe allergic reactions.

9. Is Tocimab IV Infusion 200 mg/10 ml safe for pregnant women?

Tocimab IV Infusion 200 mg/10 ml is categorized as a pregnancy category C drug, meaning that it should only be used during pregnancy if the potential benefits outweigh the risks. Consult your doctor if you are pregnant or planning to become pregnant.

10. Can Tocimab IV Infusion 200 mg/10 ml be used during breastfeeding?

It is not known whether Tocimab IV Infusion 200 mg/10 ml passes into breast milk. Caution is recommended, and you should discuss with your healthcare provider whether to continue breastfeeding while taking this medication.

11. What is the typical dosage of Tocimab IV Infusion 200 mg/10 ml for rheumatoid arthritis?

The typical dosage for rheumatoid arthritis is an initial dose of 4 mg/kg administered via IV infusion every 4 weeks. Depending on the patient's response, the dose may be increased to 8 mg/kg.

12. How long does it take for Tocimab IV Infusion 200 mg/10 ml to work?

Patients with rheumatoid arthritis may start to notice improvement in symptoms within 2 to 4 weeks of starting Tocimab IV Infusion 200 mg/10 ml. However, the full therapeutic effect may take several months to be evident.

13. Can Tocimab IV Infusion 200 mg/10 ml be used for children?

Tocimab IV Infusion 200 mg/10 ml is approved for use in children aged 2 years and older for the treatment of systemic juvenile idiopathic arthritis. The dosing is adjusted based on the child's weight and age.

14. What should I do if I miss a dose of Tocimab IV Infusion 200 mg/10 ml?

If you miss a dose of Tocimab IV Infusion 200 mg/10 ml, contact your healthcare provider for guidance on when to schedule the next dose. It is important to stay on a consistent dosing schedule to maintain the medication's effectiveness.

15. Can Tocimab IV Infusion 200 mg/10 ml interact with other medications?

Tocimab IV Infusion 200 mg/10 ml can interact with other medications, particularly immunosuppressive drugs and other biologic therapies. It may also interact with certain vaccines and anticoagulants. Inform your healthcare provider about all medications you are taking.

16. What is the risk of infections while taking Tocimab IV Infusion 200 mg/10 ml?

Tocimab IV Infusion 200 mg/10 ml can increase the risk of infections, including serious infections like tuberculosis, pneumonia, and sepsis. Patients should be monitored for signs of infection and tested for tuberculosis before starting treatment.

17. Can Tocimab IV Infusion 200 mg/10 ml cause liver problems?

Yes, Tocimab IV Infusion 200 mg/10 ml can cause liver enzyme elevations, and in rare cases, it can lead to liver damage. Liver function should be regularly monitored during treatment.

18. Can Tocimab IV Infusion 200 mg/10 ml be used for other autoimmune diseases?

While Tocimab IV Infusion 200 mg/10 ml is primarily used for rheumatoid arthritis and systemic juvenile idiopathic arthritis, it is being investigated for other autoimmune diseases, such as lupus and scleroderma. Its use may be considered in certain cases depending on the disease and its severity.

19. How should Tocimab IV Infusion 200 mg/10 ml be stored?

Tocimab IV Infusion 200 mg/10 ml should be stored in a refrigerator at 2°C to 8°C (36°F to 46°F). It should not be frozen. Keep the medication in its original packaging to protect it from light.

20. Can Tocimab IV Infusion 200 mg/10 ml be used for ankylosing spondylitis?

While Tocimab IV Infusion 200 mg/10 ml is not specifically approved for ankylosing spondylitis, it may be used off-label in certain cases where other treatments have failed, particularly if the disease is associated with high levels of inflammation.

21. What are the potential risks of taking Tocimab IV Infusion 200 mg/10 ml?

The risks of Tocimab IV Infusion 200 mg/10 ml include increased susceptibility to infections, liver damage, blood disorders, and gastrointestinal issues. It is important to undergo regular monitoring during treatment.

22. Does Tocimab IV Infusion 200 mg/10 ml increase the risk of cancer?

There is a potential increased risk of certain types of cancer, such as lymphoma, in patients taking Tocimab IV Infusion 200 mg/10 ml. However, the overall risk is considered low, and this should be discussed with your healthcare provider before starting treatment.

23. Can Tocimab IV Infusion 200 mg/10 ml be used in combination with methotrexate?

Yes, Tocimab IV Infusion 200 mg/10 ml is often used in combination with methotrexate for the treatment of rheumatoid arthritis. The combination can improve efficacy in managing symptoms and slowing disease progression.

24. How is Tocimab IV Infusion 200 mg/10 ml administered for cytokine release syndrome (CRS)?

For cytokine release syndrome, Tocimab IV Infusion 200 mg/10 ml is typically administered intravenously as a single dose. Additional doses may be given if the symptoms persist or recur.

25. What are the signs of an allergic reaction to Tocimab IV Infusion 200 mg/10 ml?

Signs of an allergic reaction to Tocimab IV Infusion 200 mg/10 ml include rash, itching, difficulty breathing, swelling of the face or throat, and dizziness. Seek immediate medical attention if these symptoms occur.

26. Is Tocimab IV Infusion 200 mg/10 ml effective for psoriatic arthritis?

While Tocimab IV Infusion 200 mg/10 ml is not FDA-approved for psoriatic arthritis, it has been shown to be effective in treating certain cases of psoriatic arthritis, particularly those with high levels of inflammation.

27. Can Tocimab IV Infusion 200 mg/10 ml cause high blood pressure?

Yes, Tocimab IV Infusion 200 mg/10 ml can cause an increase in blood pressure. Blood pressure should be monitored regularly during treatment, and any significant changes should be addressed with a healthcare provider.

28. What precautions should be taken before starting Tocimab IV Infusion 200 mg/10 ml?

Before starting Tocimab IV Infusion 200 mg/10 ml, patients should be tested for tuberculosis and other infections. A history of liver disease or blood disorders should also be reviewed. Regular monitoring is required during treatment.

29. Can Tocimab IV Infusion 200 mg/10 ml be used in elderly patients?

Tocimab IV Infusion 200 mg/10 ml can be used in elderly patients, but they may be at a higher risk for side effects, particularly infections and liver problems. Close monitoring is necessary during treatment.

30. What is the role of Tocimab IV Infusion 200 mg/10 ml in treating giant cell arteritis?

Tocimab IV Infusion 200 mg/10 ml is used to treat giant cell arteritis by reducing inflammation in the arteries, which can help prevent complications such as vision loss or stroke.

31. Is Tocimab IV Infusion 200 mg/10 ml safe for people with a history of tuberculosis?

Patients with a history of tuberculosis should be carefully evaluated before starting Tocimab IV Infusion 200 mg/10 ml. The drug can increase the risk of reactivating latent tuberculosis, so appropriate testing and preventive treatment may be required.

32. Can Tocimab IV Infusion 200 mg/10 ml be used for systemic lupus erythematosus (SLE)?

Tocimab IV Infusion 200 mg/10 ml is not FDA-approved for the treatment of lupus, but it may be considered for off-label use in severe cases that involve significant inflammation and high IL-6 levels.

33. How does Tocimab IV Infusion 200 mg/10 ml affect cholesterol levels?

Tocimab IV Infusion 200 mg/10 ml can lead to increases in cholesterol levels, particularly LDL cholesterol. Regular monitoring of lipid levels is recommended during treatment.

34. Can Tocimab IV Infusion 200 mg/10 ml be used to treat inflammation in inflammatory bowel disease (IBD)?

While Tocimab IV Infusion 200 mg/10 ml is not typically used for IBD, its role in reducing inflammation may be explored in specific cases where other treatments have not been effective.

35. Does Tocimab IV Infusion 200 mg/10 ml affect the immune system?

Yes, Tocimab IV Infusion 200 mg/10 ml suppresses certain aspects of the immune system by inhibiting IL-6, which can increase the risk of infections and reduce the body's ability to fight off diseases.

36. Can Tocimab IV Infusion 200 mg/10 ml cause weight gain?

Weight gain is not a common side effect of Tocimab IV Infusion 200 mg/10 ml, but some individuals may experience fluid retention, which could lead to mild weight gain.

37. Can Tocimab IV Infusion 200 mg/10 ml be used for vasculitis?

Tocimab IV Infusion 200 mg/10 ml has shown effectiveness in treating certain types of vasculitis, especially those associated with elevated IL-6 levels. It may be used off-label for this purpose under careful medical supervision.

38. How does Tocimab IV Infusion 200 mg/10 ml affect kidney function?

Tocimab IV Infusion 200 mg/10 ml can affect kidney function in some patients, particularly those with pre-existing kidney issues. Kidney function should be monitored during treatment, and any significant changes should be addressed promptly.

39. Can Tocimab IV Infusion 200 mg/10 ml be used to treat rheumatoid arthritis in people with liver disease?

Tocimab IV Infusion 200 mg/10 ml should be used with caution in people with liver disease, as it can cause liver enzyme elevations. Close monitoring of liver function is necessary during treatment.

40. What should I do if I experience severe side effects from Tocimab IV Infusion 200 mg/10 ml?

If you experience severe side effects, such as trouble breathing, swelling of the face, or signs of an infection, seek immediate medical attention. Your doctor may need to adjust your dosage or discontinue treatment.

41. Can Tocimab IV Infusion 200 mg/10 ml be used for osteoarthritis?

Tocimab IV Infusion 200 mg/10 ml is not typically used for osteoarthritis, as the condition involves different mechanisms of inflammation. However, it may be considered in certain cases with significant inflammatory components.

42. How does Tocimab IV Infusion 200 mg/10 ml compare to other biologic therapies?

Tocimab IV Infusion 200 mg/10 ml is one of several biologic therapies used to treat inflammatory diseases. It targets IL-6, while other biologics may target different molecules, such as TNF-alpha (e.g., etanercept, infliximab). The choice of biologic depends on the patient's condition and response to treatment.

43. How long can Tocimab IV Infusion 200 mg/10 ml be used for rheumatoid arthritis?

Tocimab IV Infusion 200 mg/10 ml can be used long-term for rheumatoid arthritis, as long as the patient continues to respond well to the medication and does not experience severe side effects. Regular monitoring is required during long-term use.

44. Can Tocimab IV Infusion 200 mg/10 ml cause hair loss?

Hair loss is not a common side effect of Tocimab IV Infusion 200 mg/10 ml, but some patients may experience hair thinning or changes in hair texture due to the effects of the medication.

45. Can Tocimab IV Infusion 200 mg/10 ml be used for multiple sclerosis?

Tocimab IV Infusion 200 mg/10 ml is not approved for the treatment of multiple sclerosis (MS), but its potential use in MS may be explored in clinical trials, particularly for its effects on inflammation.

46. How does Tocimab IV Infusion 200 mg/10 ml affect blood cell counts?

Tocimab IV Infusion 200 mg/10 ml can cause changes in blood cell counts, including a decrease in white blood cells, red blood cells, and platelets. Regular blood tests are needed to monitor these levels during treatment.

47. Can Tocimab IV Infusion 200 mg/10 ml cause diarrhea?

Diarrhea is a potential side effect of Tocimab IV Infusion 200 mg/10 ml, though it is not very common. Patients who experience persistent or severe diarrhea should contact their doctor.

48. Can Tocimab IV Infusion 200 mg/10 ml be used for sarcoidosis?

Tocimab IV Infusion 200 mg/10 ml is not typically used for sarcoidosis, but it may be considered off-label in certain cases with significant inflammation or poor response to other treatments.

49. What are the benefits of Tocimab IV Infusion 200 mg/10 ml?

The main benefits of Tocimab IV Infusion 200 mg/10 ml include its ability to reduce inflammation, improve joint function, and decrease pain and damage in conditions like rheumatoid arthritis and systemic juvenile idiopathic arthritis.

50. How should I prepare for a Tocimab IV Infusion 200 mg/10 ml infusion?

Before a Tocimab IV Infusion 200 mg/10 ml infusion, you will be monitored for any signs of allergic reactions. It is also essential to ensure that you do not have active infections or a history of tuberculosis. Make sure to inform your healthcare provider of any health changes before starting treatment.

Medical review

Last reviewed: 24 Jul 2026

Medically reviewed by:

This is general information, not personal medical advice. Consult a doctor before taking any medicine.

Tocimab IV Infusion