Oral bioavailability

evidence_span

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experimental_model

Tracer study of tritiated mebendazole given intravenously and orally to one man

exposure

A 1.7 microgram tracer dose by each route

limitations

A single subject and a tracer dose far below any therapeutic amount, so the bioavailability figure is a lower bound on the problem rather than a population value.

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

Swallowed, roughly one sixth of the drug reaches the bloodstream.

primary_references

[mbz-p7126419] The pharmacokinetics and bioavailability of mebendazole in man: a pilot study using [3H]-mebendazole. (1982). https://pubmed.ncbi.nlm.nih.gov/7126419/ DOI: 10.1111/j.1365-2125.1982.tb02008.x

tissue_or_cell_type

Whole body

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 407–418

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Tracer study of tritiated mebendazole given intravenously and orally to one man · source_derived_draft · unverified_draft

### mbz-bioavailability-17-percent Following intravenous administration of a 1.7 microgram tracer dose of tritiated mebendazole to a man an elimination half-life of 1.16 hours was observed with a volume of distribution of 2.03 litres per kilogram, after oral administration of the same dose the elimination half-life was 0.74 hours, and the bioavailability of mebendazole from the solution was found to be 17%. 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: Swallowed, roughly one sixth of the drug reaches the bloodstream. organism: Human tissue_or_cell_type: Whole body experimental_model: Tracer study of tritiated mebendazole given intravenously and orally to one man limitations: A single subject and a tracer dose far below any therapeutic amount, so the bioavailability figure is a lower bound on the problem rather than a population value. exposure: A 1.7 microgram tracer dose by each route evidence_span: {"source_cache": "artifacts/mebendazole-research/7126419.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "7b69c414a01f82e177ec37b4f362337caf7327e294a13c97d299e9a7ae80a456", "start_char": 0, "end_char": 381, "text_sha256": "7b69c414a01f82e177ec37b4f362337caf7327e294a13c97d299e9a7ae80a456"} [mbz-p7126419] The pharmacokinetics and bioavailability of mebendazole in man: a pilot study using [3H]-mebendazole. (1982). https://pubmed.ncbi.nlm.nih.gov/7126419/ DOI: 10.1111/j.1365-2125.1982.tb02008.x

evidence_span

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experimental_model

Radioimmunoassay of mebendazole and flubendazole across rats, dogs and man

exposure

Oral, subcutaneous and intramuscular dosing, and a twentyfold oral dose escalation of flubendazole in man

limitations

The dose-escalation arm is about flubendazole rather than mebendazole, and is recorded under flubendazole; it is retained because it demonstrates the solubility limit that governs this whole class.

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

Rat, dog and human

plain_language

Twenty times the dose gave less than half again as much in the blood, because it simply will not dissolve.

primary_references

[mbz-p7103610] The pharmacokinetics of mebendazole and flubendazole in animals and man. (1982). https://pubmed.ncbi.nlm.nih.gov/7103610/

tissue_or_cell_type

Plasma

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 459–470

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Radioimmunoassay of mebendazole and flubendazole across rats, dogs and man · source_derived_draft · unverified_draft

### mbz-dose-escalation-fails Absorption of oral flubendazole in man was markedly enhanced when the drug was taken together with a meal, but a twenty times higher dose produced only an increase by a factor of 1.4 in plasma levels and area under the curve, indicating that absorption is limited by the extremely poor solubility of the drug in the contents of the gastrointestinal tract; in rats plasma levels of oral and subcutaneous mebendazole were about ten times higher than those of flubendazole. 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: Twenty times the dose gave less than half again as much in the blood, because it simply will not dissolve. organism: Rat, dog and human tissue_or_cell_type: Plasma experimental_model: Radioimmunoassay of mebendazole and flubendazole across rats, dogs and man limitations: The dose-escalation arm is about flubendazole rather than mebendazole, and is recorded under flubendazole; it is retained because it demonstrates the solubility limit that governs this whole class. exposure: Oral, subcutaneous and intramuscular dosing, and a twentyfold oral dose escalation of flubendazole in man evidence_span: {"source_cache": "artifacts/mebendazole-research/7103610.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "e582dcb4657e254dfe61d437d899b2db4d2a4628aa1267fb90de6366b7b4c8f0", "start_char": 0, "end_char": 948, "text_sha256": "e582dcb4657e254dfe61d437d899b2db4d2a4628aa1267fb90de6366b7b4c8f0"} [mbz-p7103610] The pharmacokinetics of mebendazole and flubendazole in animals and man. (1982). https://pubmed.ncbi.nlm.nih.gov/7103610/

evidence_span

{"source_cache": "artifacts/sildenafil-research/10219969.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "e8a54758a045a866a0807663e835df338d7b9d650790d7202426425ce056eb58", "start_char": 0, "end_char": 1621, "text_sha256": "e8a54758a045a866a0807663e835df338d7b9d650790d7202426425ce056eb58"}

experimental_model

Pharmacokinetics after single intravenous and oral doses of labelled and unlabelled drug across five species

exposure

Carbon-14 labelled sildenafil with excretion balance and metabolite profiling

limitations

Cross-species pharmacokinetics with a mass balance. Single doses.

nutrient_topic

Sildenafil research collection; topical membership is not evidence of a direct clinical effect, and the drug is recorded separately from its N-desmethyl metabolite and its target enzyme from the homologous retinal PDE6. · Sildenafil

organism

Mouse, rat, rabbit, dog and human

plain_language

It is absorbed completely, cut down by the liver on the way through, and the main breakdown product reaches about half the parent exposure.

primary_references

[sil-p10219969] Pharmacokinetics and metabolism of sildenafil in mouse, rat, rabbit, dog and man. (1999). https://pubmed.ncbi.nlm.nih.gov/10219969/ DOI: 10.1080/004982599238687

tissue_or_cell_type

Whole body

Sildenafil: the enzyme it occupies instead of the substrate, why it cannot start a signal it can only preserve, the organic nitrate interaction that follows from that, the homologous retinal enzyme ten-fold away, and the pulmonary circulation where the same mechanism became a second indication (2026-09-22) · lines 444–455

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Pharmacokinetics after single intravenous and oral doses of labelled and unlabelled drug across five species · source_derived_draft · unverified_draft

### sil-handling-and-metabolites In man absorption from the gastrointestinal tract was essentially complete with time to maximum concentration at approximately one hour or less, bioavailability was attenuated by pre-systemic hepatic metabolism in all species, the elimination half-life in man was 3.7 hours, the majority of radioactivity was excreted in faeces with no unchanged drug detected in human excreta, five principal metabolic pathways operated in all species including piperazine N-demethylation, and following oral doses the areas under the curve for the piperazine N-desmethyl and N,N-desethyl metabolites were 55 and 27% that of the parent compound. Condition category: normal nutrient_topic: Sildenafil research collection; topical membership is not evidence of a direct clinical effect, and the drug is recorded separately from its N-desmethyl metabolite and its target enzyme from the homologous retinal PDE6. plain_language: It is absorbed completely, cut down by the liver on the way through, and the main breakdown product reaches about half the parent exposure. organism: Mouse, rat, rabbit, dog and human tissue_or_cell_type: Whole body experimental_model: Pharmacokinetics after single intravenous and oral doses of labelled and unlabelled drug across five species limitations: Cross-species pharmacokinetics with a mass balance. Single doses. exposure: Carbon-14 labelled sildenafil with excretion balance and metabolite profiling evidence_span: {"source_cache": "artifacts/sildenafil-research/10219969.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "e8a54758a045a866a0807663e835df338d7b9d650790d7202426425ce056eb58", "start_char": 0, "end_char": 1621, "text_sha256": "e8a54758a045a866a0807663e835df338d7b9d650790d7202426425ce056eb58"} [sil-p10219969] Pharmacokinetics and metabolism of sildenafil in mouse, rat, rabbit, dog and man. (1999). https://pubmed.ncbi.nlm.nih.gov/10219969/ DOI: 10.1080/004982599238687

availability_state

biomarker_context Imported condition classification; unverified.

evidence_span

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experimental_model

Plasma concentrations in three volunteers given 1.5 gram doses and in patients on long-term treatment

exposure

1.5 gram oral doses given with and without a fatty meal

limitations

Three volunteers. The finding that concentrations were measurable only with food is the substantive result; the cholestasis observation is a single patient.

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

Without fat in the meal the drug does not reach the blood at all, and between patients the levels vary from nothing to a great deal.

primary_references

[mbz-p7418715] Plasma concentrations of mebendazole during treatment of echinococcosis: preliminary results. (1980). https://pubmed.ncbi.nlm.nih.gov/7418715/ DOI: 10.1007/bf00558451

tissue_or_cell_type

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 420–431

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Plasma concentrations in three volunteers given 1.5 gram doses and in patients on long-term treatment · source_derived_draft · unverified_draft

### mbz-food-is-required When 1.5 gram doses were given to three volunteers, measurable plasma concentrations of 17 to 134 nanomoles per litre were found only if mebendazole was given together with a fatty meal, in a patient with cholestasis plasma concentrations were higher than in the three normal subjects, and in patients on long-term treatment the increase in plasma concentration after a 1 gram dose varied between 0 and 500 nanomoles per litre, so that monitoring plasma levels during long-term therapy appears advisable. 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: Without fat in the meal the drug does not reach the blood at all, and between patients the levels vary from nothing to a great deal. organism: Human tissue_or_cell_type: Plasma experimental_model: Plasma concentrations in three volunteers given 1.5 gram doses and in patients on long-term treatment limitations: Three volunteers. The finding that concentrations were measurable only with food is the substantive result; the cholestasis observation is a single patient. exposure: 1.5 gram oral doses given with and without a fatty meal evidence_span: {"source_cache": "artifacts/mebendazole-research/7418715.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "b3e200ec505a4a58edacfcf8a51f1073d528d8fc7718fd5cd10a6ca15cbded10", "start_char": 0, "end_char": 812, "text_sha256": "b3e200ec505a4a58edacfcf8a51f1073d528d8fc7718fd5cd10a6ca15cbded10"} [mbz-p7418715] Plasma concentrations of mebendazole during treatment of echinococcosis: preliminary results. (1980). https://pubmed.ncbi.nlm.nih.gov/7418715/ DOI: 10.1007/bf00558451

evidence_span

{"source_cache": "artifacts/mebendazole-research/7335116.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "358adb37f881bf9fc64cf4cea24ce690792e958df702a705b2addda3295ad144", "start_char": 0, "end_char": 1621, "text_sha256": "358adb37f881bf9fc64cf4cea24ce690792e958df702a705b2addda3295ad144"}

experimental_model

Colchicine and tritiated mebendazole binding to partially purified tubulin from Ascaris suum intestine and porcine brain

exposure

In vitro incubation of Ascaris suum with 10 micromolar mebendazole, with tubulin partially purified from the intestine

limitations

Measures the tissue mebendazole actually damages rather than embryonic tissue, and reaches the opposite conclusion about selectivity. Solubility prevented a precise association constant for mebendazole itself.

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

Nematode and pig

plain_language

Measured in the worm’s gut rather than its embryos, the drug is only about twice as selective, which is not enough to explain its safety.

primary_references

[mbz-p7335116] Intestinal tubulin as possible target for the chemotherapeutic action of mebendazole in parasitic nematodes. (1981). https://pubmed.ncbi.nlm.nih.gov/7335116/ DOI: 10.1016/0166-6851(81)90064-5

tissue_or_cell_type

Nematode intestinal tubulin and porcine brain tubulin

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 134–145

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Colchicine and tritiated mebendazole binding to partially purified tubulin from Ascaris suum intestine and porcine brain · source_derived_draft · unverified_draft

### mbz-selectivity-only-twofold Mebendazole inhibited colchicine binding to partially purified Ascaris suum intestinal tubulin competitively with an inhibition constant of 4.22 x 10-6 molar and inhibited colchicine binding to porcine brain tubulin competitively with an inhibition constant of 8.0 x 10-6 molar, so that in view of the small difference in drug binding abilities it remains unclear whether the selective toxicity can be solely explained by interference with the parasite microtubular system, and the authors suggest that differential pharmacokinetic behaviour between parasite and host may be the essential basis for the difference in susceptibility. 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: Measured in the worm’s gut rather than its embryos, the drug is only about twice as selective, which is not enough to explain its safety. organism: Nematode and pig tissue_or_cell_type: Nematode intestinal tubulin and porcine brain tubulin experimental_model: Colchicine and tritiated mebendazole binding to partially purified tubulin from Ascaris suum intestine and porcine brain limitations: Measures the tissue mebendazole actually damages rather than embryonic tissue, and reaches the opposite conclusion about selectivity. Solubility prevented a precise association constant for mebendazole itself. exposure: In vitro incubation of Ascaris suum with 10 micromolar mebendazole, with tubulin partially purified from the intestine evidence_span: {"source_cache": "artifacts/mebendazole-research/7335116.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "358adb37f881bf9fc64cf4cea24ce690792e958df702a705b2addda3295ad144", "start_char": 0, "end_char": 1621, "text_sha256": "358adb37f881bf9fc64cf4cea24ce690792e958df702a705b2addda3295ad144"} [mbz-p7335116] Intestinal tubulin as possible target for the chemotherapeutic action of mebendazole in parasitic nematodes. (1981). https://pubmed.ncbi.nlm.nih.gov/7335116/ DOI: 10.1016/0166-6851(81)90064-5

evidence_span

{"source_cache": "artifacts/mebendazole-research/7094986.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "5948d6b41d6cf4fa0b334caac010a171c49b81afd433f1eb704b4d07cfcb86cd", "start_char": 0, "end_char": 1256, "text_sha256": "5948d6b41d6cf4fa0b334caac010a171c49b81afd433f1eb704b4d07cfcb86cd"}

experimental_model

Plasma monitoring of mebendazole and its metabolites in twelve patients treated for cystic hydatid disease

exposure

10 milligrams per kilogram, with tissue sampled at surgery in two patients

limitations

Twelve patients with wide between-patient variation. The enterohepatic recycling explanation is the authors’ inference from the metabolite profile.

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

The same dose gives one patient thirty times the blood level of another.

primary_references

[mbz-p7094986] Clinical pharmacokinetics of high dose mebendazole in patients treated for cystic hydatid disease. (1982). https://pubmed.ncbi.nlm.nih.gov/7094986/ DOI: 10.1007/bf00542462

tissue_or_cell_type

Plasma, tissue and cyst material

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 433–444

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Plasma monitoring of mebendazole and its metabolites in twelve patients treated for cystic hydatid disease · source_derived_draft · unverified_draft

### mbz-variation-is-enormous In twelve patients given 10 milligrams per kilogram for cystic hydatid disease the plasma concentration-time profiles differed considerably, with elimination half-lives from 2.8 to 9.0 hours, time to peak from 1.5 to 7.25 hours and peak concentrations from 17.5 to 500 nanograms per millilitre, and the mean peak after an initial dose of 69.5 nanograms per millilitre was lower than during chronic therapy at 137.4 nanograms per millilitre. 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 same dose gives one patient thirty times the blood level of another. organism: Human tissue_or_cell_type: Plasma, tissue and cyst material experimental_model: Plasma monitoring of mebendazole and its metabolites in twelve patients treated for cystic hydatid disease limitations: Twelve patients with wide between-patient variation. The enterohepatic recycling explanation is the authors’ inference from the metabolite profile. exposure: 10 milligrams per kilogram, with tissue sampled at surgery in two patients evidence_span: {"source_cache": "artifacts/mebendazole-research/7094986.abstract.txt", "locator": "Indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "5948d6b41d6cf4fa0b334caac010a171c49b81afd433f1eb704b4d07cfcb86cd", "start_char": 0, "end_char": 1256, "text_sha256": "5948d6b41d6cf4fa0b334caac010a171c49b81afd433f1eb704b4d07cfcb86cd"} [mbz-p7094986] Clinical pharmacokinetics of high dose mebendazole in patients treated for cystic hydatid disease. (1982). https://pubmed.ncbi.nlm.nih.gov/7094986/ DOI: 10.1007/bf00542462