Component

Mebendazole polymorph A

Mebendazole polymorph A. Species, exposure and limitations are retained in each linked claim.

5 recorded relationships. Experimental role, claim status and evidence remain attached to each record.

Read recorded mechanisms Open recursive mind map

How nutrients influence it

Every nutrient with a recorded effect on this component, credited to the nutrient that acted rather than the chapter that recorded it. Open a nutrient to see the findings and the conditions they were measured under.

How nutrients reach it in more than one step

Chains of two or more recorded steps that end here, grouped by the nutrient they start from. Each step is a separate finding, so a chain is a route a mechanism could take, not proof that it does.

Tracing routes…

What it does

Every recorded relationship this component is part of, grouped by its role. Plain wording comes first; the technical statement follows.

Recorded relationships

What it acts on

  1. In 958 children randomly allocated to seven treatment groups, the efficacy of single-dose 300 milligrams of polymorph A was not different from the placebo control at the 0.05 level in both hookworm and Trichuris infections, while the egg reduction and cure rates of 300 and 500 milligrams of polymorph C were similar to each other though inferior to the standard 100 milligrams twice daily for three days.

    Mebendazole polymorph A → Cure rate and egg reduction rate in treated infection source_derived_draftungraded
    Experimental context and source evidence
    availability_state
    biomarker_context Imported condition classification; unverified.
    evidence_span
    {"source_cache": "artifacts/mebendazole-research/7939946.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "972b8bb36b68b1f40fba5f7bdb38668e9d1c40cba27ddeb19db16a3bcf29053d", "start_char": 0, "end_char": 698, "text_sha256": "972b8bb36b68b1f40fba5f7bdb38668e9d1c40cba27ddeb19db16a3bcf29053d"}
    experimental_model
    Randomised seven-arm trial in 958 schoolchildren in Southern Thailand
    exposure
    Single doses of 300 milligrams polymorph A, 300 and 500 milligrams polymorph C, against placebo and against 100 milligrams polymorph C twice daily for three days
    limitations
    The only human record here that varies the crystal form, with a placebo arm. It is a single-dose comparison and does not follow reinfection.
    nutrient_topic
    Mebendazole research collection; topical membership is not evidence of a direct clinical effect, and mebendazole is recorded separately from albendazole, from the benzimidazole class and from its own crystal forms. · Mebendazole
    organism
    Human
    plain_language
    In children, a full dose of the wrong crystal form worked no better than a sugar pill.
    primary_references
    [mbz-p7939946] Efficacy of single-dose mebendazole, polymorphic forms A and C, in the treatment of hookworm and Trichuris infections. (1993). https://pubmed.ncbi.nlm.nih.gov/7939946/
    tissue_or_cell_type
    Hookworm and Trichuris infection
    trigger_kind
    biomarker_context Imported condition classification; unverified.

    Mebendazole: the tubulin it binds, why that is selective, the crystal form that decides whether any of it works, and the off-target that became an oncology programme (2026-09-22) · lines 368–379

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Randomised seven-arm trial in 958 schoolchildren in Southern Thailand · source_derived_draft · unverified_draft

    ### mbz-polymorph-a-equals-placebo In 958 children randomly allocated to seven treatment groups, the efficacy of single-dose 300 milligrams of polymorph A was not different from the placebo control at the 0.05 level in both hookworm and Trichuris infections, while the egg reduction and cure rates of 300 and 500 milligrams of polymorph C were similar to each other though inferior to the standard 100 milligrams twice daily for three days. Condition category: biomarker_context nutrient_topic: Mebendazole research collection; topical membership is not evidence of a direct clinical effect, and mebendazole is recorded separately from albendazole, from the benzimidazole class and from its own crystal forms. plain_language: In children, a full dose of the wrong crystal form worked no better than a sugar pill. organism: Human tissue_or_cell_type: Hookworm and Trichuris infection experimental_model: Randomised seven-arm trial in 958 schoolchildren in Southern Thailand limitations: The only human record here that varies the crystal form, with a placebo arm. It is a single-dose comparison and does not follow reinfection. exposure: Single doses of 300 milligrams polymorph A, 300 and 500 milligrams polymorph C, against placebo and against 100 milligrams polymorph C twice daily for three days evidence_span: {"source_cache": "artifacts/mebendazole-research/7939946.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "972b8bb36b68b1f40fba5f7bdb38668e9d1c40cba27ddeb19db16a3bcf29053d", "start_char": 0, "end_char": 698, "text_sha256": "972b8bb36b68b1f40fba5f7bdb38668e9d1c40cba27ddeb19db16a3bcf29053d"} [mbz-p7939946] Efficacy of single-dose mebendazole, polymorphic forms A and C, in the treatment of hookworm and Trichuris infections. (1993). https://pubmed.ncbi.nlm.nih.gov/7939946/
    Complete structured claim and evidence

  2. Testing the biological activity of the three polymorphic forms of mebendazole called A, B and C by median lethal dose in mice after oral and intraperitoneal administration and by anthelmintic effect against the enteral and parenteral phases of Trichinella spiralis, the polymorphic form A was the least toxic and the least effective, and use of polymorph C was judged advisable for oral treatment given its lower toxicity than form B and similar anthelmintic effect.

    Mebendazole polymorph A → Cure rate and egg reduction rate in treated infection source_derived_draftungraded
    Experimental context and source evidence
    evidence_span
    {"source_cache": "artifacts/mebendazole-research/3608627.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "cf4b94d7b266abf376ded706272be7f440f6f46b82db5ee9c36d2c34af6e8825", "start_char": 0, "end_char": 608, "text_sha256": "cf4b94d7b266abf376ded706272be7f440f6f46b82db5ee9c36d2c34af6e8825"}
    experimental_model
    Median lethal dose and anthelmintic efficacy of three mebendazole polymorphs in mice
    exposure
    Polymorphs A, B and C given orally and intraperitoneally, against enteral and parenteral phases of infection
    limitations
    Tests toxicity and efficacy of the three solid forms in the same animals. Numerical values for the median lethal doses are not given in the abstract and are not assumed here.
    nutrient_topic
    Mebendazole research collection; topical membership is not evidence of a direct clinical effect, and mebendazole is recorded separately from albendazole, from the benzimidazole class and from its own crystal forms. · Mebendazole
    organism
    Mouse
    plain_language
    One crystal form of the same molecule barely poisons the mouse and barely touches the worm.
    primary_references
    [mbz-p3608627] Experimental chemotherapy and toxicity in mice of three mebendazole polymorphic forms. (1987). https://pubmed.ncbi.nlm.nih.gov/3608627/ DOI: 10.1159/000238506
    tissue_or_cell_type
    Whole body and Trichinella spiralis infection

    Mebendazole: the tubulin it binds, why that is selective, the crystal form that decides whether any of it works, and the off-target that became an oncology programme (2026-09-22) · lines 355–366

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Median lethal dose and anthelmintic efficacy of three mebendazole polymorphs in mice · source_derived_draft · unverified_draft

    ### mbz-polymorph-a-is-inert Testing the biological activity of the three polymorphic forms of mebendazole called A, B and C by median lethal dose in mice after oral and intraperitoneal administration and by anthelmintic effect against the enteral and parenteral phases of Trichinella spiralis, the polymorphic form A was the least toxic and the least effective, and use of polymorph C was judged advisable for oral treatment given its lower toxicity than form B and similar anthelmintic effect. Condition category: normal nutrient_topic: Mebendazole research collection; topical membership is not evidence of a direct clinical effect, and mebendazole is recorded separately from albendazole, from the benzimidazole class and from its own crystal forms. plain_language: One crystal form of the same molecule barely poisons the mouse and barely touches the worm. organism: Mouse tissue_or_cell_type: Whole body and Trichinella spiralis infection experimental_model: Median lethal dose and anthelmintic efficacy of three mebendazole polymorphs in mice limitations: Tests toxicity and efficacy of the three solid forms in the same animals. Numerical values for the median lethal doses are not given in the abstract and are not assumed here. exposure: Polymorphs A, B and C given orally and intraperitoneally, against enteral and parenteral phases of infection evidence_span: {"source_cache": "artifacts/mebendazole-research/3608627.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "cf4b94d7b266abf376ded706272be7f440f6f46b82db5ee9c36d2c34af6e8825", "start_char": 0, "end_char": 608, "text_sha256": "cf4b94d7b266abf376ded706272be7f440f6f46b82db5ee9c36d2c34af6e8825"} [mbz-p3608627] Experimental chemotherapy and toxicity in mice of three mebendazole polymorphic forms. (1987). https://pubmed.ncbi.nlm.nih.gov/3608627/ DOI: 10.1159/000238506
    Complete structured claim and evidence

  3. Of four raw materials of mebendazole examined, three were polymorph C and the other was polymorph A or a mixture of forms A and B, with X-ray powder diffractometry and infrared spectroscopy indicating form B while the much slower powder dissolution suggested polymorph A; the literature prescribes use of polymorph C pharmaceutically, generic manufacturers should be aware that forms other than C are still available on the market, and all four mebendazole tablets then available in South Africa contained polymorph C.

    Mebendazole polymorph A → Aqueous solubility and dissolution rate of the solid drug source_derived_draftungraded
    Experimental context and source evidence
    evidence_span
    {"source_cache": "artifacts/mebendazole-research/9876612.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "c0cb5ad093307edd2cbaee474418c3086cd524c606eaddd1cae7186ed962fd26", "start_char": 0, "end_char": 666, "text_sha256": "c0cb5ad093307edd2cbaee474418c3086cd524c606eaddd1cae7186ed962fd26"}
    experimental_model
    Preformulation analysis of four mebendazole raw materials and four marketed tablets
    exposure
    X-ray powder diffractometry, infrared spectroscopy and powder dissolution
    limitations
    A small survey in one country at one time. It also shows the analytical methods disagreeing with each other on one sample, which is recorded.
    nutrient_topic
    Mebendazole research collection; topical membership is not evidence of a direct clinical effect, and mebendazole is recorded separately from albendazole, from the benzimidazole class and from its own crystal forms. · Mebendazole
    organism
    Pharmaceutical product
    plain_language
    The inactive form is still sold as raw material, and the tests used to tell the forms apart do not always agree.
    primary_references
    [mbz-p9876612] Identification of the mebendazole polymorphic form present in raw materials and tablets available in South Africa. (1998). https://pubmed.ncbi.nlm.nih.gov/9876612/ DOI: 10.3109/03639049809085647
    tissue_or_cell_type
    Raw material and tablets

    Mebendazole: the tubulin it binds, why that is selective, the crystal form that decides whether any of it works, and the off-target that became an oncology programme (2026-09-22) · lines 394–405

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Preformulation analysis of four mebendazole raw materials and four marketed tablets · source_derived_draft · unverified_draft

    ### mbz-wrong-form-reaches-market Of four raw materials of mebendazole examined, three were polymorph C and the other was polymorph A or a mixture of forms A and B, with X-ray powder diffractometry and infrared spectroscopy indicating form B while the much slower powder dissolution suggested polymorph A; the literature prescribes use of polymorph C pharmaceutically, generic manufacturers should be aware that forms other than C are still available on the market, and all four mebendazole tablets then available in South Africa contained polymorph C. Condition category: normal nutrient_topic: Mebendazole research collection; topical membership is not evidence of a direct clinical effect, and mebendazole is recorded separately from albendazole, from the benzimidazole class and from its own crystal forms. plain_language: The inactive form is still sold as raw material, and the tests used to tell the forms apart do not always agree. organism: Pharmaceutical product tissue_or_cell_type: Raw material and tablets experimental_model: Preformulation analysis of four mebendazole raw materials and four marketed tablets limitations: A small survey in one country at one time. It also shows the analytical methods disagreeing with each other on one sample, which is recorded. exposure: X-ray powder diffractometry, infrared spectroscopy and powder dissolution evidence_span: {"source_cache": "artifacts/mebendazole-research/9876612.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "c0cb5ad093307edd2cbaee474418c3086cd524c606eaddd1cae7186ed962fd26", "start_char": 0, "end_char": 666, "text_sha256": "c0cb5ad093307edd2cbaee474418c3086cd524c606eaddd1cae7186ed962fd26"} [mbz-p9876612] Identification of the mebendazole polymorphic form present in raw materials and tablets available in South Africa. (1998). https://pubmed.ncbi.nlm.nih.gov/9876612/ DOI: 10.3109/03639049809085647
    Complete structured claim and evidence

What acts on it

  1. In an accelerated stability study, form C was converted to the thermodynamically stable and least soluble form A with increased temperature and moisture, the transformation was significantly increased at constant temperature and humidity when trace amounts of form A were already present, four of the seven products tested contained trace amounts of form A, in some tablets transformation was so quick that it reduced shelf life to less than one month, and tablet dissolution of those products was reduced to the extent that it did not comply with USP and FDA specifications.

    Mebendazole polymorph C → Mebendazole polymorph A source_derived_draftungraded
    Experimental context and source evidence
    evidence_span
    {"source_cache": "artifacts/mebendazole-research/19691117.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "6005cbf9afb4151467910164f873d0956382c3bcc10cac8514326385b32e32b1", "start_char": 0, "end_char": 1296, "text_sha256": "6005cbf9afb4151467910164f873d0956382c3bcc10cac8514326385b32e32b1"}
    experimental_model
    Accelerated stability study of mebendazole tablets under ICH storage conditions
    exposure
    Storage at 30 degrees with 65% relative humidity and at 40 degrees with 75% relative humidity
    limitations
    Solid-state kinetics on marketed products, modelled with the Johnson-Mehl-Avrami-Erofeyev-Kolmogorov equation. It measures dissolution rather than patient outcome.
    nutrient_topic
    Mebendazole research collection; topical membership is not evidence of a direct clinical effect, and mebendazole is recorded separately from albendazole, from the benzimidazole class and from its own crystal forms. · Mebendazole
    organism
    Pharmaceutical product
    plain_language
    The working form of the drug turns into the useless form on the shelf, faster if a trace of the useless form is already there.
    primary_references
    [mbz-p19691117] Characterization of polymorph transformations that decrease the stability of tablets containing the WHO essential drug mebendazole. (2010). https://pubmed.ncbi.nlm.nih.gov/19691117/ DOI: 10.1002/jps.21899
    tissue_or_cell_type
    Tablets

    Mebendazole: the tubulin it binds, why that is selective, the crystal form that decides whether any of it works, and the off-target that became an oncology programme (2026-09-22) · lines 381–392

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Accelerated stability study of mebendazole tablets under ICH storage conditions · source_derived_draft · unverified_draft

    ### mbz-crystal-form-sets-solubility In an accelerated stability study, form C was converted to the thermodynamically stable and least soluble form A with increased temperature and moisture, the transformation was significantly increased at constant temperature and humidity when trace amounts of form A were already present, four of the seven products tested contained trace amounts of form A, in some tablets transformation was so quick that it reduced shelf life to less than one month, and tablet dissolution of those products was reduced to the extent that it did not comply with USP and FDA specifications. Condition category: normal nutrient_topic: Mebendazole research collection; topical membership is not evidence of a direct clinical effect, and mebendazole is recorded separately from albendazole, from the benzimidazole class and from its own crystal forms. plain_language: The working form of the drug turns into the useless form on the shelf, faster if a trace of the useless form is already there. organism: Pharmaceutical product tissue_or_cell_type: Tablets experimental_model: Accelerated stability study of mebendazole tablets under ICH storage conditions limitations: Solid-state kinetics on marketed products, modelled with the Johnson-Mehl-Avrami-Erofeyev-Kolmogorov equation. It measures dissolution rather than patient outcome. exposure: Storage at 30 degrees with 65% relative humidity and at 40 degrees with 75% relative humidity evidence_span: {"source_cache": "artifacts/mebendazole-research/19691117.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "6005cbf9afb4151467910164f873d0956382c3bcc10cac8514326385b32e32b1", "start_char": 0, "end_char": 1296, "text_sha256": "6005cbf9afb4151467910164f873d0956382c3bcc10cac8514326385b32e32b1"} [mbz-p19691117] Characterization of polymorph transformations that decrease the stability of tablets containing the WHO essential drug mebendazole. (2010). https://pubmed.ncbi.nlm.nih.gov/19691117/ DOI: 10.1002/jps.21899
    Complete structured claim and evidence

Where it participates (unsigned role)

  1. Polymorph B and polymorph C both increased survival in a GL261 glioma model with B exhibiting greater toxicity, polymorph A showed no benefit, B and C both reached brain concentrations exceeding the GL261 half-maximal inhibitory concentration 29-fold, polymorph C demonstrated a 24-hour brain-to-plasma area-under-curve ratio of 0.82 while B showed higher plasma exposure and a lower ratio, polymorph A presented markedly lower levels in both plasma and brain, and combination with elacridar significantly improved the efficacy of polymorph C in glioma and medulloblastoma models.

    Mebendazole polymorph C → Brain to plasma exposure ratio source_derived_draftungraded
    Experimental context and source evidence
    availability_state
    biomarker_context Imported condition classification; unverified.
    evidence_span
    {"source_cache": "artifacts/mebendazole-research/25862759.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "7545a89b4d17461bbe2d8ac8c7f3093b6ae0ce2f20307ab57b524d91f4f827c3", "start_char": 0, "end_char": 1682, "text_sha256": "7545a89b4d17461bbe2d8ac8c7f3093b6ae0ce2f20307ab57b524d91f4f827c3"}
    experimental_model
    Polymorph content of marketed and custom tablets measured by infrared spectroscopy, then tested in orthotopic mouse glioma and medulloblastoma models with LC/MS pharmacokinetics
    exposure
    Polymorphs A, B and C, alone and with the transporter inhibitor elacridar
    limitations
    Carries the polymorph distinction across from the anthelmintic use into the oncology use and finds it decides brain exposure. Mouse models, and elacridar is an experimental tool rather than a co-therapy.
    nutrient_topic
    Mebendazole research collection; topical membership is not evidence of a direct clinical effect, and mebendazole is recorded separately from albendazole, from the benzimidazole class and from its own crystal forms. · Mebendazole
    organism
    Mouse
    plain_language
    The same crystal form that works against worms is the one that gets into the brain; the inert form stays out of the blood entirely.
    primary_references
    [mbz-p25862759] Brain Penetration and Efficacy of Different Mebendazole Polymorphs in a Mouse Brain Tumor Model. (2015). https://pubmed.ncbi.nlm.nih.gov/25862759/ DOI: 10.1158/1078-0432.ccr-14-2681
    tissue_or_cell_type
    Brain and plasma
    trigger_kind
    biomarker_context Imported condition classification; unverified.

    Mebendazole: the tubulin it binds, why that is selective, the crystal form that decides whether any of it works, and the off-target that became an oncology programme (2026-09-22) · lines 524–535

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Polymorph content of marketed and custom tablets measured by infrared spectroscopy, then tested in orthotopic mouse glioma and medulloblastoma models with LC/MS pharmacokinetics · source_derived_draft · unverified_draft

    ### mbz-polymorph-decides-brain-levels Polymorph B and polymorph C both increased survival in a GL261 glioma model with B exhibiting greater toxicity, polymorph A showed no benefit, B and C both reached brain concentrations exceeding the GL261 half-maximal inhibitory concentration 29-fold, polymorph C demonstrated a 24-hour brain-to-plasma area-under-curve ratio of 0.82 while B showed higher plasma exposure and a lower ratio, polymorph A presented markedly lower levels in both plasma and brain, and combination with elacridar significantly improved the efficacy of polymorph C in glioma and medulloblastoma models. Condition category: biomarker_context nutrient_topic: Mebendazole research collection; topical membership is not evidence of a direct clinical effect, and mebendazole is recorded separately from albendazole, from the benzimidazole class and from its own crystal forms. plain_language: The same crystal form that works against worms is the one that gets into the brain; the inert form stays out of the blood entirely. organism: Mouse tissue_or_cell_type: Brain and plasma experimental_model: Polymorph content of marketed and custom tablets measured by infrared spectroscopy, then tested in orthotopic mouse glioma and medulloblastoma models with LC/MS pharmacokinetics limitations: Carries the polymorph distinction across from the anthelmintic use into the oncology use and finds it decides brain exposure. Mouse models, and elacridar is an experimental tool rather than a co-therapy. exposure: Polymorphs A, B and C, alone and with the transporter inhibitor elacridar evidence_span: {"source_cache": "artifacts/mebendazole-research/25862759.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "7545a89b4d17461bbe2d8ac8c7f3093b6ae0ce2f20307ab57b524d91f4f827c3", "start_char": 0, "end_char": 1682, "text_sha256": "7545a89b4d17461bbe2d8ac8c7f3093b6ae0ce2f20307ab57b524d91f4f827c3"} [mbz-p25862759] Brain Penetration and Efficacy of Different Mebendazole Polymorphs in a Mouse Brain Tumor Model. (2015). https://pubmed.ncbi.nlm.nih.gov/25862759/ DOI: 10.1158/1078-0432.ccr-14-2681
    Complete structured claim and evidence

In the sources

Preserved passages that mention this component, quoted exactly. Open one to read it in context.

    This is a research prototype built from draft material. It is not medical advice, and its statements still await verification against the original studies.

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