Abstract
Objective The present investigation entailed determination of effect of diverse cross-linking
agents on Losartan Potassium loaded chitosan microspheres. The emulsion cross-linking
method was employed to formulate the microspheres with an endeavour to achieve maximum
sustained effect.
Methods The FTIR studies revealed absence of any interaction between Losartan and chitosan.
The emulsion cross linking method was accomplished in three steps encompassing formation
of an aqueous and oily phase, emulsification and cross-linking. A total of eighteen
Losartan formulations were developed using six different cross-linkers at three varying
level were screened for optimum parameters. The in vitro drug release parameters of optimum formulations (LC3, LE3, LF3, LG3, LS3 and LV3)
containing citric acid, epichlorohydrin, formaldehyde, glutaraldehyde, suphuric acid
and vanillin as cross-linkers were assessed to determine the sustained effect.
Results The values of evaluated parameters including percent yield (94.67%), average particle
size (51.19 µm), drug content (44.38 mg) and entrapment efficiency (88.77%) connoted
LG3 as the best formulation. Additionally, the values of relative measure of skewness
(β1=0.01 and γ1=0.10) and platykurtic (β2=1.26) size distribution were least for LG3 with spherical shape and smooth surface
as revealed by SEM studies.
Conclusion The outcome of in vitro release and other characterizations of microspheres explicitly revealed glutaraldehyde
as the best cross-linker amongst the cross-linkers used herewith. The maximum sustained
effect (lasting over a period of 24 h) accompanied with higher MDT and t50% with lower%DE and Q14h values thus corroborated the objective of attaining sustained release of Losartan.
Key words
losartan potassium - chitosan - cross-linking agents - emulsion cross-linking - sustained
drug delivery
