Pohl Roderike, Hauser Robert, Li Ming, De Souza Errol, Feldstein Robert, Seibert Richard, Ozhan Koray, Kashyap Nandini, Steiner Solomon
Biodel Inc., Danbury, Connecticut 06810, USA.
J Diabetes Sci Technol. 2012 Jul 1;6(4):755-63. doi: 10.1177/193229681200600404.
In order to enhance the absorption of insulin following subcutaneous injection, excipients were selected to hasten the dissociation rate of insulin hexamers and reduce their tendency to reassociate postinjection. A novel formulation of recombinant human insulin containing citrate and disodium ethylenediaminetetraacetic acid (EDTA) has been tested in clinic and has a very rapid onset of action in patients with diabetes. In order to understand the basis for the rapid insulin absorption, in vitro experiments using analytical ultracentrifugation, protein charge assessment, and light scattering have been performed with this novel human insulin formulation and compared with a commercially available insulin formulation [regular human insulin (RHI)].
Analytical ultracentrifugation and dynamic light scattering were used to infer the relative distributions of insulin monomers, dimers, and hexamers in the formulations. Electrical resistance of the insulin solutions characterized the overall net surface charge on the insulin complexes in solution.
The results of these experiments demonstrate that the zinc chelating (disodium EDTA) and charge-masking (citrate) excipients used in the formulation changed the properties of RHI in solution, making it dissociate more rapidly into smaller, charge-masked monomer/dimer units, which are twice as rapidly absorbed following subcutaneous injection than RHI (Tmax 60 ± 43 versus 120 ± 70 min).
The combination of rapid dissociation of insulin hexamers upon dilution due to the zinc chelating effects of disodium EDTA followed by the inhibition of insulin monomer/dimer reassociation due to the charge-masking effects of citrate provides the basis for the ultra-rapid absorption of this novel insulin formulation.
为提高皮下注射后胰岛素的吸收，选用辅料以加速胰岛素六聚体的解离速率，并降低其注射后重新缔合的倾向。一种含柠檬酸盐和乙二胺四乙酸二钠（EDTA）的重组人胰岛素新制剂已在临床进行测试，对糖尿病患者具有非常快速的起效作用。为了解胰岛素快速吸收的基础，已使用分析超速离心、蛋白质电荷评估和光散射对这种新型人胰岛素制剂进行了体外实验，并与市售胰岛素制剂[常规人胰岛素（RHI）]进行了比较。
采用分析超速离心和动态光散射来推断制剂中胰岛素单体、二聚体和六聚体的相对分布。胰岛素溶液的电阻表征了溶液中胰岛素复合物的总体净表面电荷。
这些实验结果表明，制剂中使用的锌螯合剂（乙二胺四乙酸二钠）和电荷屏蔽剂（柠檬酸盐）改变了溶液中RHI的性质，使其更快地解离成更小的、电荷屏蔽的单体/二聚体单元，皮下注射后其吸收速度是RHI的两倍（达峰时间分别为60±43分钟和120±70分钟）。
由于乙二胺四乙酸二钠的锌螯合作用，胰岛素六聚体在稀释时快速解离，随后由于柠檬酸盐的电荷屏蔽作用抑制胰岛素单体/二聚体重新缔合，这为这种新型胰岛素制剂的超快速吸收提供了基础。
