In the pharmaceutical industry, the fixed-dose combination (FDC) of Lamivudine (150 mg) and Zidovudine (300 mg) is a foundational dual-NRTI (Nucleoside Reverse Transcriptase Inhibitor) backbone for HIV therapy. As a pharmacist and manufacturer, I view this combination as a critical component of Highly Active Antiretroviral Therapy (HAART), designed to simplify dosing and reduce the “pill burden” for patients.

Primary Clinical Uses

• HIV-1 Infection: Used in combination with at least one other antiretroviral (such as a Protease Inhibitor or an NNRTI) to manage HIV. It is not a cure but effectively slows the progression of the disease.

• Post-Exposure Prophylaxis (PEP): It is a standard regimen for healthcare workers or individuals who have had a potential occupational or non-occupational exposure to HIV, usually taken for 28 days.

• Prevention of Mother-to-Child Transmission (PMTCT): Used during pregnancy and labor to reduce the risk of transmitting HIV to the fetus.

Mechanism of Action: Dual Chain Termination

Both drugs are pro-drugs that must be phosphorylated within the cell to their active triphosphate forms.

Competitive Inhibition: They compete with natural deoxynucleosides for a spot in the viral DNA chain being built by the enzyme Reverse Transcriptase.

The “Fake” Building Block: Because these molecules lack a 3′-hydroxyl group, once they are incorporated into the viral DNA string, no further building blocks can be added.

Viral Suppression: This leads to DNA chain termination, preventing the virus from converting its RNA into DNA and stopping it from integrating into the human host cell’s genome.

The Manufacturer’s Perspective: Technical & Export

From a production standpoint in a WHO-GMP facility, this FDC requires specific attention to stability and bioequivalence:

• Bioequivalence (BE) Challenges: As a firm owner, you know that achieving BE against the innovator (Combivir) is essential for export. We conduct rigorous dissolution testing in multiple pH media to ensure the release profiles of both APIs meet international standards.

• Zidovudine Stability: Zidovudine is sensitive to light. At our Mumbai facility, we utilize opaque PVC/PVDC or Alu-Alu blister packaging to prevent degradation and ensure a 36-month shelf life.

• Market Position: While many markets have moved toward Tenofovir-based backbones, the Lamivudine + Zidovudine combination remains vital for patients who cannot tolerate Tenofovir (e.g., those with renal issues).

• B2B & Dossiers: We provide the full eCTD Dossier and stability data required for registration in Zone IVb markets (Africa, SE Asia), making this a high-volume product for institutional tenders.