Background: In this study, four nanoparticle formulations (F1 to F4) comprising varying
ratios of alginate, Pluronic F-68 and calcium chloride with a constant amount of insulin and chitosan as a
coating material were prepared using polyelectrolyte complexation and ionotropic gelation methods to
protect insulin against enzymatic degradation.
Methods: This study describes the formulation design, optimisation, characterisation and evaluation of
insulin concentration via oral delivery in rats. A reversed-phase high-performance liquid chromatography
(HPLC) method was developed and validated to quantify insulin concentration in rat plasma. The
proposed method produced a linear response over the concentration range of 0.39 to 50 µg/ml.
Results: In vitro release study showed that dissolution of insulin in simulated gastric juice of pH 1.2 was
prevented by alginate core and chitosan coating but rapidly released in simulated intestinal fluid (pH
6.8). Additionally, Formulation 3 (F3) has a particle size of 340.40 ± 2.39 nm with narrow uniformity
exhibiting encapsulation efficiency (EE) of 72.78 ± 1.25 % produced highest absorption profile of insulin
with a bioavailability of 40.23 ±1.29% and reduced blood glucose after its oral administration in rats.
Conclusion: In conclusion, insulin oral delivery system containing alginate and chitosan as a coating
material has the ability to protect the insulin from enzymatic degradation thus enhance its absorption in
the intestine. However, more work should be done for instance to involve human study to materialise
this delivery system for human use.