Background: Repeated administrations of insulin injection on daily basis evoke pain and numerous
complications with adverse effects on the diabetic patients’ life quality. Moreover, wearing insulin pump is also
associated with several problems of diabetic ketoacidosis, catheter site infection, contact dermatitis and high cost.
Method: We have developed an in situ gel system, consisting of insulin-loaded liposomes dispersed within a
thermoreversible gel (Pluronic® F127 gel), which increases the duration of insulin action for the treatment of
diabetes. Vesicular phospholipid gel technique was used to encapsulate the insulin into liposomes.
Results: The resulting liposomal gel formulation had a longer drug-release period in vitro than a free insulin
solution or liposomes and Pluronic® F127 gel individually. Furthermore, the addition of liposomes to the
Pluronic® F127 gel improved the stability of the encapsulated insulin at a physiological temperature. In vivo
study was performed to investigate the bioactivity and absorption of insulin released from the liposomal gel and
other formulations. The liposomal gel released insulin into the bloodstream continuously for up to 7 days and
significantly enhanced drug bioavailability compared to insulin released from liposomes or Pluronic® F127 gel
individually. Blood glucose levels were reduced for up to 4 days. Histology data demonstrated excellent biocompatibility
of the Pluronic® F127 gel-based delivery systems, with no observable inflammatory response in rat
Conclusion: Obtained results show that the insulin-loaded liposomes dispersed within Pluronic® F127 gel can be
used as a long-acting drug delivery system, and replacement for conventional insulin therapy.