Abstract:
In the present study, novel colloidal nanoparticulate in situ gel of Timolol maleate
was investigated for its potential use to improve ophthalmic delivery of the drug. The
study was conducted in two steps, first poly lactide co- glycolic acid nanoparticles
were prepared and characterized on the basis of particle size, zeta potential and
percentage entrapment. And in second step, the drug loaded nanoparticles were
dispersed in in situ gel forming solution yielding the nanoparticulate in situ gel. The
polymeric nanoparticles were prepared by w/o/w emulsification method. The poly
lactide co- glycolic acid nanoparticles were obtained in size range of 189.4-284.9 nm
which is considered suitable for ocular delivery without irritation in to eye. The zeta
potential of the nanoparticles were obtained in range of -9.6 to -14.5 mV which
indicate the stability of nanoparticles. The polydispersivity index of of nanoparticles
fond in the range of 0.231-0.491 which indicate the mid range of polydispersivity.
The batch E6 was showed smaller particle size 189.4, high zeta potential -14.5 and
high entrapment 59.2% as compare to other batches thus selected as optimized
formulation for incorporation into in situ gel containing carbopol 934P 1% and
HPMC K4M 0.5 % which was showed immediate gelation and optimum viscosity. The mechanism of drug release from nanoparticulate in situ gel was observed to
follow higuchi model on the basis of R2 value of mathematical kinetic models. The
data obtained in this study thus suggest that nanoparticulate in situ gel of Timolol
maleate was successfully designed to give sustained drug delivery.
