Conflict of Interests None of the authors of this paper have any financial interest that has influenced the inhibitor bulk results or interpretation of this paper. Acknowledgments The authors thank Tania Vazquez for editorial

assistance; also they are grateful to E. Carro, G. Orive, R. M. Hernandez, and J. L. Pedraz for their kind help and collaboration. This work was supported in part by grants from the Xunta de Galicia (INCITE2009, 09CSA051905PR and INCITE08E1R905078ES) and the Fondo de Investigación Sanitaria (PI10/02628 and RD09/0076/00011), and the “Isidro Parga Pondal” programme.
Diabetes is Inhibitors,research,lifescience,medical a rapidly growing health problem worldwide Inhibitors,research,lifescience,medical and chronic disease wherein the pancreas does not produce enough insulin (type 1 diabetes), or the body does not respond correctly to insulin and relative insulin deficiency (type 2 diabetes). It can be a life-threatening disease and can also lead to serious complications such as cardiovascular disease, kidney failure, blindness, and nerve damage [1–3]. According to the World Health Organization, the number of people living with diabetes is estimated to increase from 172 million in 2000

to 366 million Inhibitors,research,lifescience,medical in 2030 [4]. The global diabetes epidemic has devastating effects on not only patients and their families but also national economies. Human insulin is a major backbone for the treatment of diabetes. Although human insulin has thorough contributed much in clinical treatment

of diabetes for a long time, there are still some difficulties and challenges of hypoglycemia and short half-life. Inhibitors,research,lifescience,medical In order to overcome these drawbacks, insulin glargine (Lantus), an insulin analogue (C267H404N72O78S6, MW = 6,063) was developed by replacing asparagine at the position of 21 of Inhibitors,research,lifescience,medical the A chain with glycine, and two arginines were added to the C-terminus of the B chain in human insulin (Figure 1). It has a prolonged duration of action after subcutaneous injection and, therefore, can provide a basal insulin level for 24 hours by once daily injection Cilengitide [5]. This alteration results in low aqueous solubility at neutral pH [6]. Insulin glargine is supplied in an acidic solution, which becomes neutralized at the injection site, leading to the formation of microprecipitates from which insulin glargine is slowly released into the circulation [6]. Figure 1 Amino acid sequence and location of intermolecular disulfide bonds of insulin glargine. Cyclodextrins (CyDs) are known to form inclusion complexes with various guest molecules [7, 8]. However, the low aqueous solubility of natural CyDs, especially β-CyD, has restricted their range of applications. To improve their solubility, alkylated, hydroxyl alkylated, sulfated, sulfobutyl alkylated, and branched CyDs have been developed [9–12].