Implementing Analytical Quality by Design (AQbD) for the Development of a Stability-Indicating Method for Tapentadol HCl in Bulk Drug and Nasal Spray

Abstract

Purpose: To develop and validate a stability-indicating RP-HPLC method for quantifying Tapentadol HCl in bulk drug and
nasal spray formulation using Analytical Quality by Design (AQbD) principles, addressing a critical gap in the literature for
nasal spray formulations.
Methods: A Central Composite Design (CCD) optimized critical method parameters: mobile phase pH (4.5–5.5), flow rate
(0.8–1.2 mL/min) and aqueous phase proportion (60–70%). Forced degradation studies under acid, alkaline, oxidative, thermal,
and photolytic conditions assessed stability-indicating capability. Method validation followed ICH Q2(R1) guidelines.
Results: Optimized conditions—triethylammonium acetate buffer (10 mM, pH 5.0): acetonitrile (65:35, v/v) at 1.0 mL/min—
achieved baseline resolution between Tapentadol and degradation products (Rs1 = 3.5, Rs2 = 2.8) with retention time of 7.738
min. Tapentadol HCl showed marked susceptibility to oxidative degradation (16.55% under 3% H₂O₂) while remaining stable
under photolytic and thermal conditions. The method demonstrated excellent linearity (r² = 0.999 over 2–12 μg/mL), accuracy
(mean recovery 99.9–100.1%), precision (%RSD < 0.5%) and sensitivity (LOD = 0.2 μg/mL, LOQ = 0.7 μg/mL). Successful
application to Tapease NS Nasal Spray (label claim 225 mg/mL) yielded 99.69% recovery (%RSD = 0.38%), confirming
practical utility.
Conclusion: This AQbD-driven, stability-indicating RP-HPLC method offers a robust, reliable, and regulatory-compliant
approach for routine quality control and stability testing of Tapentadol HCl in both bulk drug and innovative nasal spray
formulations with particular value for oxidative degradation monitoring.