The Pharmacist

Page: 14-20

Background: Tirzepatide is a novel dual glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) receptor agonist with significant clinical value in type 2 diabetes mellitus management. Analytical methods enabling accurate, robust, and stability-indicating quantification are essential for quality control of bulk and dosage forms.

Aim and Objective: To develop and validate a simple, precise, and stability-indicating reverse-phase high-performance liquid chromatography (RP-HPLC) method for estimation of tirzepatide in bulk drug and pharmaceutical dosage form, in accordance with ICH Q2(R1) guidelines.

Materials and Methods: Chromatographic separation was achieved using an Agilent Eclipse XDB C18 column (150 × 4.6 mm, 3.5 µm) with an isocratic mobile phase of acetonitrile and 0.1% triethylamine buffer (pH 2.5, adjusted with orthophosphoric acid) in the ratio of 30:70 (v/v), at a flow rate of 1.0 mL/min. Detection was carried out at 234 nm with a 10 µL injection volume. Method validation parameters evaluated included specificity, linearity, accuracy, precision, robustness, and sensitivity (LOD/LOQ). Forced degradation studies under acid, alkali, oxidative, reductive, hydrolytic, photolytic, and thermal stress were performed to confirm stability-indicating capability.

Results: Tirzepatide eluted at 2.563 min with sharp and symmetrical peaks (tailing factor 1.15, plate count 10,524). The method showed excellent linearity over 25–150 µg/mL (r² = 0.99979), recoveries within 99.4–101.1% (mean 100.1%), and precision with %RSD < 2. Robustness testing under varied flow rates and mobile-phase ratios confirmed method resilience. Sensitivity studies yielded LOD and LOQ values of 0.60 µg/mL and 2.00 µg/mL, respectively. Forced degradation indicated maximum degradation under oxidative (11.6%) and reductive (12.6%) conditions, while thermal, photolytic, and hydrolytic conditions caused only minor changes; in all cases, peak purity remained intact.

Conclusion: The validated RP-HPLC method is accurate, precise, robust, and stability-indicating. Its short runtime, reproducibility, and simplicity make it highly suitable for routine quality control and stability testing of tirzepatide in pharmaceutical laboratories.