UV-Visible Spectrophotometric Method Development and Validation for The Estimation of Levodopa in Nasal Medium

Objective: The objective of this study was to develop a straightforward UV-Visible spectrophotometric method for the quantitative analysis of Levodopa in both its pure form and pharmaceutical dosage forms, followed by validation of the proposed analytical method in accordance with standard guidelines. Material and Methods: Quantitative analysis of Levodopa was performed using a UV-Visible double-beam spectrophotometer, with measurements taken at the maximum absorbance wavelength (280 nm) in phosphate-buffered saline (pH 6.4) to simulate the nasal environment. The drug was initially characterized through melting point determination using the capillary fusion method and further confirmed by Fourier Transform Infrared (FTIR) spectroscopy. A novel UV-Visible spectrophotometric method was developed for the estimation of Levodopa, and its validation was conducted in accordance with International Conference on Harmonisation (ICH) guidelines, evaluating key analytical parameters such as linearity, accuracy, precision, repeatability, sensitivity, robustness and ruggedness. Result: The melting point of the drug was determined to be 277 °C, which aligns with its reported reference range, confirming its identity. Further structural confirmation was achieved through spectral interpretation. A linear relationship was observed for Levodopa in the concentration range of 1–6 µg/mL, exhibiting a regression coefficient (R²) of 0.9988, indicating strong linearity. The precision of the method was assessed, with intraday and interday relative standard deviation (RSD) values found to be 0.734% and 0.720%, respectively—both within acceptable limits. To evaluate the sensitivity of the developed method, the limit of detection (LOD) and limit of quantification (LOQ) were calculated as 0.810 µg/mL and 2.452 µg/mL, respectively. Conclusion: The UV spectrophotometric method developed and validated for the analysis of Levodopa demonstrated acceptable linearity, accuracy, and precision, and proved to be cost-effective, making it suitable for routine quality control and quantitative evaluation of its pharmaceutical formulations. Keywords: UV visible spectrometric, Levodopa, validation, nasal media, saline phosphate buffer pH 6.4