ABD 400 – Albendazole 400 mg EU

ABD 400 is a film-coated oral tablet containing Albendazole 400 mg as the active pharmaceutical ingredient, manufactured by Intas Pharmaceuticals Ltd., an established Indian pharmaceutical company with a global presence. Albendazole is a broad-spectrum, synthetic benzimidazole carbamate anthelmintic agent included on the WHO Model List of Essential Medicines​.

The compound is one of the most versatile and widely deployed anti-parasitic agents in global public health, effective against a broad range of intestinal and tissue-dwelling helminths, including roundworms (nematodes), tapeworms (cestodes), and certain protozoa. The 400 mg tablet is the standard adult dose and is central to mass drug administration programmes for controlling soil-transmitted helminthiasis and lymphatic filariasis worldwide.

Unlike many anthelmintics that act only within the gut, Albendazole is partially absorbed systemically, allowing it to target tissue-dwelling parasites such as the larval stages of Taenia solium (neurocysticercosis) and Echinococcus granulosus (hydatid disease).

Chemical Information

• Chemical Name: Methyl [5-(propylthio)-1H-benzimidazol-2-yl]carbamate
• Molecular Formula: C₁₂H₁₅N₃O₂S
• Molecular Weight: 265.33 g/mol
• CAS Number: 54965-21-8
• Chemical Class: Benzimidazole carbamate
• Structural Characteristics: Benzimidazole bicyclic ring system with a carbamate group at the 2-position and a propylthio substituent at the 5-position. The propylthio side chain contributes to lipophilicity, influencing tissue penetration and bioavailability.

Albendazole is a white to off-white crystalline powder, practically insoluble in water, with poor aqueous solubility that significantly limits its oral bioavailability unless administered with a fatty meal.

Mechanism of Action

The primary mechanism is selective inhibition of β-tubulin polymerisation in susceptible parasites, disrupting microtubule formation.

Primary Molecular Target: β-Tubulin

Albendazole binds with high affinity to the colchicine-sensitive site of parasite β-tubulin, preventing polymerisation of tubulin dimers into microtubules. Microtubules are essential for mitotic spindle formation, intracellular transport, maintenance of cell shape, and glucose uptake in the parasite tegument and intestinal cells.

Downstream Consequences

1. Impaired glucose uptake​, leading to glycogen depletion and reduced ATP synthesis.
2. Degenerative changes in the endoplasmic reticulum and mitochondria.
3. Decreased ATP production​, causing muscular paralysis and metabolic failure.
4. Immobilisation and death of the parasite, followed by expulsion through peristalsis or host immune clearance.

Selectivity for Parasite Tubulin

Albendazole binds to helminth β-tubulin with markedly higher affinity than mammalian tubulin. This differential binding provides the basis for its selective toxicity and explains why therapeutic concentrations are well tolerated in humans while producing potent parasiticidal effects.

Pharmacological Effects

In-Vitro Findings

Albendazole and its active metabolite, albendazole sulfoxide, inhibit motility and viability of Ascaris lumbricoides​, Trichuris trichiura​, hookworm species, and Strongyloides stercoralis in a concentration-dependent manner. Larval and adult cestodes (​Taenia​, Echinococcus​) also show high in-vitro susceptibility.

Animal Findings

Animal studies have demonstrated high cure rates against gastrointestinal nematodes, dose-dependent efficacy against experimental echinococcosis, and radiological resolution of cerebral cysts in the porcine model of neurocysticercosis.

Human Clinical Evidence

Albendazole has well-established clinical efficacy:

• Soil-transmitted helminthiasis: A single 400 mg oral dose achieves cure rates of 95–100% for Ascaris lumbricoides, 70–90% for hookworm​, and 40–60% for Trichuris trichiura.
• Neurocysticercosis: At 15 mg/kg/day for 8–30 days with corticosteroids, 60–85% of patients show complete or partial cyst resolution with reduced seizure frequency.
• Hydatid disease: Prolonged 28-day cycles produce cyst regression or stabilisation in approximately 30–40%of non-surgical patients.

Dosage

Albendazole has clearly established, validated human dosing regimens approved by regulatory authorities.Export

Indication	Adult Dose	Duration
Soil-transmitted helminthiasis	400 mg single oral dose	Single dose
Neurocysticercosis	15 mg/kg/day in 2 divided doses	8–30 days
Hydatid disease	10–15 mg/kg/day in 2 divided doses	28-day cycles, up to 3 cycles
Cutaneous larva migrans	400 mg once daily	1–3 days

Administration Instructions

• Take with a fatty meal: Bioavailability increases up to 5-fold with food.
• Tablet may be chewed, crushed, or swallowed whole.
• Children 1–2 years: 200 mg single dose; ≥2 years: 400 mg single dose for intestinal worms; weight-based dosing for systemic infections.

Pharmacokinetics

• Absorption: Less than 5% bioavailability fasting; increased up to 5-fold with a fatty meal. Tmax 2–5 hours for the active metabolite.
• Distribution: Albendazole sulfoxide distributes widely; CSF concentrations reach ~43% of plasma levels, enabling neurocysticercosis treatment. Approximately 70% plasma protein-bound.
• Metabolism: Rapid first-pass hepatic oxidation to albendazole sulfoxide (active) and subsequently to albendazole sulfone (inactive), primarily via CYP3A4.
• Half-life: 8–12 hours for albendazole sulfoxide.
• Elimination: Predominantly renal; ~87% recovered in urine within 5 days.

Side Effects and Safety

Short-term/single-dose therapy is generally well tolerated. Mild, transient effects include abdominal pain, nausea, and headache.

Prolonged high-dose therapy requires monitoring:

• Hepatotoxicity: Reversible transaminase elevation in 15–20% of patients; severe injury is rare.
• Bone marrow suppression: Reversible leucopenia, rarely agranulocytosis.
• Neurological complications in neurocysticercosis: Seizures and elevated intracranial pressure from the inflammatory response to dying cysts — corticosteroids are mandatory.
• Alopecia: Reversible hair thinning reported occasionally.

Contraindications

• Hypersensitivity to Albendazole or other benzimidazoles.
• Pregnancy: Contraindicated; animal studies show embryotoxicity. Pregnancy should be excluded before therapy.

Dependence, Tolerance and Withdrawal

Albendazole has no dependence, tolerance, or withdrawal potential and no abuse liability. It has no known activity at CNS reward pathways.

Anthelmintic resistance mediated by β-tubulin gene mutations (e.g., F200Y) is a major veterinary concern and an emerging concern in human medicine, particularly for Trichuris trichiura and hookworm species.

Harm Reduction and Safe Use

• Exclude pregnancy before treatment; avoid in the first trimester.
• Avoid combining with other hepatotoxic medications or alcohol during prolonged therapy.
• Monitor liver function and complete blood count during prolonged courses.
• Always co-administer corticosteroids in neurocysticercosis.
• Take with a fatty meal to ensure adequate absorption.
• Store at room temperature (15–30°C), protected from moisture and light.
• Keep out of reach of children.
• Dispose of unused tablets through a pharmacy or local pharmaceutical waste channels.

Legal and Regulatory Status

In India, ABD 400 is a Schedule H prescription medicine​, dispensed only upon prescription of a registered medical practitioner. Regulatory status varies by country; Albendazole is prescription-only in most jurisdictions for systemic indications. It is listed on the WHO Model List of Essential Medicines.

Research Applications

• Cytoskeletal biology: A probe for studying microtubule dynamics and tubulin pharmacology.
• Drug-resistance research: Model system for understanding benzimidazole resistance mechanisms and developing molecular diagnostics.
• Drug repurposing: Investigated preclinically for potential anti-cancer activity via microtubule inhibition; not an approved indication.
• Formulation science: Ongoing research into improving low oral bioavailability (lipid-based and nanoparticle formulations).
• Public health implementation: Cornerstone of mass drug administration programmes for neglected tropical diseases.

Conclusion

ABD 400 (Albendazole 400 mg, Intas Pharmaceuticals) is a broad-spectrum benzimidazole anthelmintic acting through selective inhibition of parasite β-tubulin polymerisation. It is a WHO Essential Medicine with well-established human efficacy against intestinal nematodes, neurocysticercosis, and hydatid disease. Key clinical considerations include up to 5-fold bioavailability enhancement with a fatty meal, mandatory corticosteroid co-administration in neurocysticercosis, and hepatic/haematological monitoring during prolonged therapy. Unlike research chemicals, Albendazole has validated human dosing, safety, and efficacy for licensed indications.

ABD 400 is a Schedule H prescription medicine intended for human therapeutic use under medical supervision. It is not a research chemical. Use only as directed by a qualified healthcare professional.