Rapid and simple methods for determination diclofenac (DF) in both chitosan films and microsphere formulations using HPLC and UV-visible spectrophotometer were developed and validated. The HPLC assay was performed using a reversed phase ACE® C8 column (150 mm x 4.6 mm) with a mobile phase system consisting of methanol : phosphate buffer pH = 2.5 (66: 34 by volume). The flow rate was set at 1 mL/min and the UV detection at 254 nm. The Hewlett Packard 8452A, Diode Array Spectrophotometer set at 278 nm was used for method comparison. The accuracies reported as % recovery were found to be 98.84-100.91% and 92.61-99.64% for the UV-vis spectrophotometer and HPLC, respectively. Inter-day precisions (reproducibility) were 0.23–0.55%RSD (UV-vis) and 1.91-2.66–0.55%RSD (HPLC), while intra-day precisions (repeatability) were 0.23–0.55%RSD (UV-vis) and 0.34–1.62%RSD (HPLC). The calibration curve was found to be linear with the equations of y = 0.0445x + 0.006 and y = 57694x - 10767 with correlation coefficients of 0.9996 and 0.9994 (r2) over a concentration range of 5–25 μg/mL for the UV-vis and HPLC, respectively with a low LOD and LOQ. The method can be applied for the quantitative analysis of diclofenac in both chitosan film and microsphere formulations without any complexity for sample preparations.