Mebendazole polymorph B

Where it participates (unsigned role)

1. 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

2. 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

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