Controlled Delivery of Basal Insulin from Phase-Sensitive Polymeric Systems After Subcutaneous Administration: In Vitro Release, Stability, Biocompatibility, In Vivo Absorption, and Bioactivity of Insulin

Basal level insulin delivery: In vitro release, stability, biocompatibility, and in vivo absorption from thermosensitive triblock copolymers

“…The sample preparation method described previously by Al-Tahami et al 28 has been used. Samples were centrifuged, filtered, and degassed under vacuum.…”

“…We have earlier described the details about the sample preparation method. 28 Spectra of buffer and insulin were scanned from 200 to 300 nm. The spectra of the buffer were used as baseline and were subsequently subtracted from insulin sample spectra.…”

“…The details of the method can be found in an earlier publication. 28 FlexAnalysis R software (Bruker Daltonics Inc., Billercia, MA) was used to analyze the data.…”

“…The detail methods for in vitro and in vivo biocompatibility are described in the previous publication. 28 Briefly, the polymers were extracted in PBS maintained at 37 • C and 70 • C for 10 days. As degradation rate of polymers is greater at higher temperature, the extract prepared at 70 • C simulates the long-term effects of the delivery system.…”

“…Recently, we demonstrated that the zinc addition to insulin (1:5 insulin hexamer-zinc ion) during the preparation of the delivery system enhanced insulin stability during release. 28 In the present study, we investigated the thermosensitive polymeric delivery system for controlled insulin delivery in vitro and in vivo in diabetic rats to meet the basal insulin requirements. The overall structural stability, which comprises conformational and chemical stability, of the in vitro-released insulin was evaluated.…”