Fig 1: PNP hydrogels for the prolonged delivery of GLP-1 RAs(A) From literature reports it is clear that once-weekly dosing frequency does not significantly improve patient compliance compared with a once-daily dosing frequency.7(B) Localized depots form in the subcutaneous space immediately after subcutaneous injection, providing a tunable platform for sustained release of GLP-1-RA compounds.(C) Clinical data showing the release profile of current GLP-1 treatments, where the black dotted line represents repeated weekly injections that patients take every week for 4 months to reach therapeutic concentrations of GLP-1 RA. In contrast, the blue line represents the target delivery profile of a single PNP hydrogel depot injection that sustains release of GLP-1 RA for 120 days. Current state-of-the-art strategies require daily or weekly subcutaneous injections with significant ramp-up time to achieve therapeutic concentrations. The red dotted line indicates the therapeutic threshold.(D) Semaglutide and liraglutide are once-weekly and once-daily, respectively, GLP-1 RA therapies that were investigated in this study.(E) PNP hydrogels prepared by mixing hydrophobically modified HPMC with PEG-PLA nanoparticles enable facile encapsulation of GLP-1-receptor agonists with 100% efficiency.
Fig 2: Preparation and characterization of GLP-1 RA-loaded PNP hydrogel formulations(A) PNP hydrogels are prepared by mixing a solution of hydrophobically modified HPMC (right syringe) with a solution of PEG-PLA nanoparticles and GLP-1 RAs (left syringe) using a Luer lock mixer. After mixing, a homogeneous, bubble-free, solid-like PNP hydrogel is formed (right syringe). Owing to their dynamic cross-linking, PNP hydrogels are injectable through clinically relevant, high-gauge needles and rapidly self-heal after injection.(B) Rheological characterization of PNP-1-10 hydrogel formulations: (i) frequency-dependent oscillatory shear sweep, (ii) stress-dependent oscillatory shear sweep, and (iii) yield stress obtained from stress sweep.(C) Rheological characterization of PNP-2-10 hydrogel formulations: (i) frequency-dependent oscillatory shear sweep, (ii) stress-dependent oscillatory shear sweep, and (iii) yield stress obtained from stress sweep.
Fig 3: Effect of PNP hydrogel formulations on weight in diabetic ratsA single administration of GLP-1 RA hydrogels reduces the overall weight gain in type 2-like diabetic male rats over the course of 6 weeks.(A) Change in weight over 6 weeks of each treatment group (n = 5–6).(B) Individual pre- and post-treatment weight for individual rats in each treatment group (n = 5–6). The p values were determined using a one-way ANOVA with Dunnett’s multiple comparisons test and using an unpaired, two-tailed t test. Table S4 lists the p values of each treatment group compared with the PBS control.
Fig 4: In vivo evaluation of PNP hydrogel formulation release kinetics in diabetic ratsSingle-dose GLP-1 RA hydrogel treatment prolongs the delivery of semaglutide and liraglutide for 6 weeks compared with a daily 20 μg semaglutide injection.(A) Treatment schedule and timing of blood glucose measurements and serum collection for analysis. Diabetic rats received a single s.c. injection of hydrogel or daily s.c. bolus injections of PBS or daily injections of 20 μg semaglutide.(B) Pharmacokinetics in diabetic rats and respective standard deviatios. Fasted male diabetic rats (n = 5–6) received subcutaneous administration of (1) high loading (S-1.2 mg) of semaglutide, (2) medium loading (S-0.9 mg) of semaglutide, or (3) low loading (S-0.6 mg) of semaglutide in the 2-10 formulation.(C) Comparison of 2-10 vs. 1-10 hydrogel formulation pharmacokinetics and respective standard deviatios with the same semaglutide loading (S-0.9 mg).(D) GLP-1 serum concentration and respective standard deviatios for the 2-10 vs. the 1-10 liraglutide hydrogels at a loading of 0.9 mg.
Fig 5: In vitro evaluation of PNP hydrogel formulation release kinetics(A) Schematic of the in vitro release assay of GLP-1 RAs from PNP hydrogels immersed in saline over 2 weeks. In vitro release assays were designed to minimize hydrogel erosion by minimizing the surface area-to-volume of the hydrogel.(B) In vitro release profiles showing the percent cumulative release of semaglutide from the 1-10 and 2-10 hydrogel formulations over the course of 2 weeks and their standard deviatios (n = 3).(C) In vitro release profiles showing the percent cumulative release of liraglutide from the 1-10 and 2-10 hydrogel formulations over the course of 2 weeks and their standard deviatios (n = 3).(D) Percent mass of cargo retained in the PNP hydrogel formulations during the release assay after the 2-week release assay show significant difference (p < 0.05).(E) Schematic of the in vitro burst release assay of the GLP-1 RAs from PNP hydrogel formulations. Samples (n = 3) were directly injected into saline and the supernatant saline was collected after 1 min. Samples were analyzed using either semaglutide- or liraglutide-specific ELISAs. The bar graph shows the percent burst release for each of the hydrogel formulations after 1 min with significant difference (p < 0.05).(F) Schematic illustrating the different release mechanisms of cargo from the PNP hydrogels.
Supplier Page from BMA Biomedicals for Liraglutide ELISA Kit