Background: Mycophenolic acid (MPA), an immunosuppressive agent, is used orally to
reduce corneal graft rejection. However, its oral use is associated with gastrointestinal side effects.
Objectives: This study aims to prepare: MPA nanoparticle eye drops and a validated analytical
Methods: Aqueous MPA eye drops were prepared by nanoencapsulation of MPA using nanomerics
MET (N-palamitoyl-N-monomethyl-N,N-dimethyl-N,N,N-trimethyl-6-O-glycolchitosan) at a
MET and MPA ratio of 7.5: 1 g g-1 in the presence of glycerol (2.75% w/w). A validated MPA formulation
drug substance assay was then conducted.
Results: MET-MPA formulations were prepared as well as a validated assay. Assay validation parameters
for the analysis of MPA in the formulation were satisfactory [Plate count = 16458, capacity
Factor = 2.4, Tailing Factor = 1.02, linearity = 0.999 (0.016-0.5 mg mL-1), limit of detection =
0.056 mg mL-1, limit of quantification = 0.17 mg mL-1, accuracy = 98%, intraday and interday relative
standard deviation = 0.45% and 4% respectively]. The candidate formulation (z-average mean
= 66 ± 0.4 nm, polydispersity index = 0.12 ± 0.012, drug content = 1.14 ± 0.003 mg mL-1, zeta potential
= +8.5 ± 1.4 mV, pH = 7.4 ± 0.02, osmolarity = 309 ± 1.5 mOSm L-1, viscosity = 1.04 ±
0.001 mPa.s) was then found to be stable for 14 days with respect to drug content at refrigeration,
room and accelerated (40ºC) temperature. All other formulation parameters were within the ocular
Conclusion: A validated assay (ICH and US FDA guidelines) for new MPA nanoparticle eye
drops has been developed.