Background/Objectives: Donepezil (DPL) is available as the hydrochloride
salt (DPL-HCL) which is highly water-soluble, prompting leakage of the drug into water
phase during solid lipid nanoparticles (SLNs) formulation which leads to less entrapment
efficiency. The drug was converted into its base form i.e. donepezil base (DPL base). The
main objective of the work was to study the physicochemical characterization and identification
of DPL base and to compare it with parent DPL-HCL, to develop a High-
Performance Liquid Chromatography (HPLC) method for the detection of DPL base in
SLNs. The purpose was the determination of entrapment efficiency as well as the shelf
life of developed SLNs.
Methods: DPL-HCL was converted into DPL base simply by alkalization of DPL- HCL
with NaOH and then extracted into dichloromethane (DCM) followed by drying to obtain
DPL base. The HPLC method was developed and validated to quantify the DPL base for
the determination of its shelf life in SLNs. The drug content in the developed SLNs was
determined by extracting the DPL base using methanol a solvent. The method was validated
for linearity, precision, accuracy, reproducibility, limit of detection (LOD) and limit
of quantification (LOQ).
Results: DPL-HCL was successfully converted into DPL base with a yield value of
88.61%. The optimized mobile phase was comprised of 0.02 M phosphate buffer (pH
7.4), methanol and ACN (40:50:10 v/v/v). The pH of mobile phase was adjusted with ophosphoric
acid. The linearity range of the developed method was found to be 0.5-80
μg/mL with LOD and LOQ value 0.086 and 0.263 μg/ml respectively. The shelf life of
the DPL base in SLNs was found to be 2.29 years.
Conclusion: The HPLC method for donepezil base was successfully developed and validated.
RSD values for validated parameters were < 2, indicating the authenticity of the
developed method. The method was successfully used for the determination of shelf life
of the drug in SLNs.