Stimuli-responsive hydrogels have enormous potential in drug delivery applications. They can be used for site-specific drug delivery due to environmental variables in the body such as pH and temperature. In this study, we have developed pH-responsive microgels for the delivery of doxorubicin (DOX) in order to optimize its anti-tumor activity while minimizing its systemic toxicity. We used a copolymer of oligo(polyethylene glycol) fumarate (OPF) and sodium methacrylate (SMA) to fabricate the pH-responsive microgels. We demonstrated that the microgels were negatively charged, and the amounts of charge on the microgels were correlated with the SMA concentration in their formulation. The resulting microgels exhibited sensitivity to the pH and ionic strength of the surrounding environment. We demonstrated that DOX was efficiently loaded into the microgels and released in a controlled fashion via an ion-exchange mechanism. Our data revealed that the DOX release was influenced by the pH and ionic strength of the solution. Moreover, we designed a phenomenological mathematical model, based on a stretched exponential function, to quantitatively analyze the cumulative release of DOX. We found a linear correlation between the maximum release of DOX calculated from the model and the SMA concentration in the microgel formulation. The anti-tumor activity of the released DOX was assessed using a human chordoma cell line. Our data revealed that OPF–SMA microgels prolonged the cell killing effect of DOX.

Although good metabolic control can reduce the risk of diabetes complications and associated costs, 1 many patients have glucose levels above goal, and hypoglycemia often complicates treatment.2 A recent meta-analysis has shown that the most efficacious strategies to improve glucose control were case management, health care team changes to provide a role for team members in addition to the primary provider, patient education, and facilitated transmission of patient data to clinicians ("facilitated relay").3 However, these approaches have not been combined and translated as needed to permit widespread use.Translation of diabetes management guidelines can also be hindered by limitations such as (1) lack of specificity in directing management of individual patients, (2) lack of algorithms that emphasize widely used, inexpensive drugs, and (3) The most efficacious strategies to improve diabetes control include case management, health care team changes, patient education, and facilitated transmission of patient data to clinicians ("facilitated relay"), but these strategies have not been translated to permit general use in clinical practice.

No abstract