title: Effects of carrier solution on insulin bioavailability.
abstract: BACKGROUND
  The aim of our study is to assess the influence of the base solution on the availability of biologic insulin expressed in the value of total insulin using the radioimmunoassay method and to monitor the influence of the base solution on the total insulin concentration over time.
  
  
  METHODS
  Total insulin in a saline and in a total nutrient admixture was measured using the RIA method. In 15 experiments, the application of the saline by a perfusor (8 IU Actrapid HM, 100 IU/1 mL + 20 mL saline) was carried out at time intervals of baseline, 5, 10, 30, 60, 90, and 210 minutes. The application of the total nutrient admixture (8 IU Actrapid HM + 20 mL total nutrient admixture) was carried out in the same way. The MANOVA, ANOVA and paired t test with Bonferroni correction were then used for statistical evaluation.
  
  
  RESULTS
  The average values of insulin concentration in saline at given time intervals were 21.5 +/- 11.3 mIU/L (5.4% of the theoretically calculated concentration). The level of insulin in the total nutrient admixture did not change over time, and it reached the values of 115.2 +/- 22.3 (28.8% of the theoretically calculated concentration). Changes in insulin concentration in time were found only in the saline (ANOVA time effect p < .001 for saline; p = .26 for total nutrient admixture).
  
  
  CONCLUSIONS
  The availability of insulin was significantly higher in the total nutrient admixture solution than in the saline in the 3.5-hour experiment. The dependence of insulin concentration on time is present only in saline, and the main changes in insulin bioavailability are within first 60 minutes. The difference could be caused by smaller insulin absorption to the syringe walls and to the set, owing to the amino acids in the mixture. The question whether the amino acid concentration affects insulin bioavailability stays opened to other studies.
authors.affiliation: Department of Medicine I, University Hospital Plzen, Plzen, Czech Republic. rusavy@fnplzen.cz
authors.forename: Zdenek
authors.initials: Z
authors.lastname: Rusavý
authors.forename: Vladimir
authors.initials: V
authors.lastname: Sramek
authors.forename: Renata
authors.initials: R
authors.lastname: Suchat
authors.forename: Silvie
authors.initials: S
authors.lastname: Lacigova
authors.forename: Ondrej
authors.initials: O
authors.lastname: Topolcan
mesh_terms: D000704:Analysis of Variance; D019540:Area Under Curve; D001682:Biological Availability; D005526:Food, Formulated; D006801:Humans; D066298:In Vitro Techniques; D007328:Insulin / Q000493:pharmacokinetics*; D010288:Parenteral Nutrition / Q000379:methods*; D011863:Radioimmunoassay
chemical_list: D007328:Insulin