Protected graft copolymer (PGC) basal formulation of insulin as potentially safer alternative to Lantus(R) (insulin-glargine): a streptozotocin-induced, diabetic Sprague Dawley rats study

PURPOSE: To develop a long-acting formulation of native human insulin with a similar pharmacodynamics (PD) profile as the insulin analogue insulin glargine (Lantus(R), Sanofi-Aventis) with the expectation of retaining native human insulin\u27s superior safety profile as insulin glargine is able to activate the insulin-like growth factor 1 (IGF-1) receptor and is linked to a number of malignancies at a higher rate than regular human insulin. METHODS: Development of protected graft copolymer (PGC) excipients that bind native human insulin non-covalently and testing blood glucose control obtained with these formulations in streptozotocin-induced diabetic Sprague Dawley rats compared to equally dosed insulin glargine. RESULTS: PGC-formulations of native human insulin are able to control blood glucose to the same extent and for the same amount of time after s.c. injection as the insulin analogue insulin glargine. No biochemical changes were made to the insulin that would change receptor binding and activation with their possible negative effects on the safety of the insulin. CONCLUSION: Formulation with the PGC excipient offers a viable alternative to biochemically changing insulin or other receptor binding peptides to improve PD properties

Organ Related Markers and Functional Test [Mean (SD); (n = 4 or 8)].

<p>Organ Related Markers and Functional Test [Mean (SD); (n = 4 or 8)].</p

Summary of Changes in Blood and Tissue Parameters With and Without Mitigation After PBI Injury.

<p>Summary of Changes in Blood and Tissue Parameters With and Without Mitigation After PBI Injury.</p

Hematologic Parameters Post Gastrointestinal Radiation Injury [Mean (SD); (n = 4)].

<p>Hematologic Parameters Post Gastrointestinal Radiation Injury [Mean (SD); (n = 4)].</p

Intestinal Cytokine levels (pg/mg protein) Post Gastrointestinal Radiation Injury [Mean (SD); (n = 4)].

<p>Intestinal Cytokine levels (pg/mg protein) Post Gastrointestinal Radiation Injury [Mean (SD); (n = 4)].</p

Regression line shows LD50/30 is 15.7 Gy.

<p>Shown is the % Mortality as a function of the partial body irradiation (PBI) dose received. Male C57BL/6J mice (9–10 weeks old; 14 animals per group) were irradiated at a dose range of 14.5–16.5 Gy using a 6MV LINAC photon source (Varian model #EX-21) while the head, forelimbs, and thorax were shielded. Following irradiation the animals were observed for 30 days. Mortality was seen in the range of 7–90% on days 6–8 after PBI. Probit analysis was done and percent mortality was plotted against radiation dose received (R² is 0.947 indicating a very good fit). The Fisher’s exact test for data points indicate there are statistically significant differences (p<0.05) between 14.5 vs. 16.0 Gy, 14.5 vs. 16.5 Gy, 15.0 vs. 16.5 Gy, and 15.5 vs. 16.5 Gy. From these data the LD30/30, LD50/30, and LD70/30 were established at the levels of 15.3 Gy at a 95% CI of 14.912–15.687 Gy, 15.7 Gy at a 95% CI of 15.307–16.082 Gy, and 16.1 Gy at a 95% CI of 15.702–16.477 Gy, respectively. With R-squared, Fisher’s exact test, and 95% CI of LD30/30, LD50/30, and LD70/30, a high correlation is demonstrated between dose and mortality.</p

Villus length and Crypt number Post Gastrointestinal Radiation Injury [Mean (SD); (n = 8)].

<p>Villus length and Crypt number Post Gastrointestinal Radiation Injury [Mean (SD); (n = 8)].</p

Kaplan-Meier Survival Curves of C57BL/6J Mice (n = 30/group), GI irradiated with 15.7 Gy (LD50/30).

<p>Twenty four hours after irradiation and daily for 7 days, mice were treated as indicated with 3 mg/kg unformulated FGF4, 3 mg/kg unformulated FGF7, 3 mg/kg PF4, 3 mg/kg PF7, PF4/7 which is 1.5 mg/kg PF4 plus 1.5 mg/kg PF7, or 60 mg/kg PGC carrier. Amifostine (300 mg/kg) used as a positive control was administered once 30 min prior to irradiation, and the sham irradiated control group remained untreated. Compared to the sham irradiated control (60% survival), significant survival advantage (≥90% survival) was provided by PF7, PF4, or unformulated FGF7 [p<0.02 by both Log-rank (Mantel-Cox) and Chi-square tests]. PF4, PF7, and Amifostine are not significantly different in preventing animal death. The PF4 and PF7 treated groups have higher survival than unformulated FGF4 or FGF7.</p

Representative Images (H&E) of Jejunum Sections at 15.7 Gy PBI in Male Mice at Day 10.

<p>A: Non-irradiated control from day 4; G: PF4; H: PF7; I: PF4 + PF7; J: Amifostine; K: Irradiated control. Pictures are 600 μm x 600 μm.</p