Purity Of Insulin Research Articles

FORMULATION AND EVALUATION OF A CHITOSAN-PVA-GELLAN INSULIN IMPLANT

Objective: The purpose of this study was to ascertain the applicability of degradable materials for fabrication of an insulin release system.Methods: Insulin implants were prepared by using poly (vinyl alcohol) (PVA), gellan and chitosan by solution casting method. The prepared implants were evaluated for swellability, content uniformity, potency and purity of insulin in implants, scanning electron microscopy studies, in vitro release studies, in vitro degradation studies using lysozyme, stability studies and circular dichroism spectroscopy.Results: The swelling degree of the implants was found to be in the range of 1.07-1.56. The diffusion coefficient of water through the implant was found to depend on the calcium chloride (CaCl2) concentration. The diffusion coefficient of insulin through the chitosan-PVA-gellan in the early stages was found to be in the range of 1.99´10-5 cm2/sec to 5.24´10-5 cm2/sec and at later stages in the range of 6.9´10-6 cm2/sec to 1.10´10-5 cm2/sec. The weight of the implants was 48±0.58 mg. The insulin content in the implants was 9.86±0.10 mg. The potency of insulin extracted from the implants was 27.11±0.75 U/mg or 95.12±2.61 % of the control insulin. The in vitro release studies showed that insulin was released completely in a period of 13-19 d depending on the composition of the implant. The increase in CaCl2 retarded the rate of insulin release whereas the increase in PVA content leads to the rapid release of insulin. The device was found to undergo significant weight loss due to enzyme mediated degradation.Conclusion: These studies provide validity for the potential utility of chitosan-PVA-gellan implant systems for the delivery of insulin. The studies also demonstrate that insulin maintained its integrity within the implant system. Implants showed the complete release of insulin in 19 d and the release of insulin from the implants depended on the amount of CaCl2.

AN ATTEMPT TO PRODUCE RECOMBINANT HORSE INSULIN

The present study aimed to produce horse insulin by use of recombinant DNA technology. Because the hormones such as somatotropin, prolactin and leptin, which are practically applicable in veterinary medicine, are also peptides, they can be obtained on the basis of this model technology. To isolate total RNA, horse pancreas samples were collected in RNA stabilizing solution from local abattoirs, sent to the laboratory, and stored the samples in the freezer at -80°C. Molecular biological reagents and kits for total RNA extraction,one step RT (reverse transcription)-PCR reactions, cloning, expression, and purification were used to produce equine proinsulin. Primers were designed from NCBI gene bank data and synthesized in Macrogen Inc, Korea. Obtained equine proinsulin was processed by enzymes trypsin and carboxypeptidase B to form mature insulin. The purity of insulin was assessed by SDS-PAGE. Molecular weight of insulin is approximately 6.0 kDa. The hormone was also measured by ELISA test and it was equal to 55 IU per ml of solution. Finally it can be concluded equine insulin with 55 IU/ml activity can be produced by recombinant DNA technology.

Insulin lipohypertrophy: A non-fatal dermatological complication of diabetes mellitus reflecting poor glycemic control

Lipohypertrophy has been a recognized complication of insulin therapy. Despite improvements in insulin purity and the introduction of recombinant human insulin, its prevalence has remained high particularly in those with a poor glycemic control. Injection of insulin into a site of lipohypertrophy, although painless, may lead to erratic absorption of insulin, with the potential for poor glycemic control and unpredictable hypoglycemia. Rotation of injection sites can reduce the frequency of the problem but does not abolish it. The importance of this complication is not only cosmetic but also in its impact on insulin absorption, and hence glycemic control. Lipohypertrophy is characterized by a benign tumor-like swelling of fatty tissue secondary to subcutaneous insulin injections. A strong association of lipoatrophy and lipohypertrophy with insulin antibodies might suggest that autoimmune phenomena with insulin play a role in the development of both. Presented here is a young type 1 diabetic on human insulin with poor glycemic control who developed lipohypertrophy at the injection sites around the umbilicus.

Type 2 diabetes in children and adolescents

Arlen L. Rosenblooma, Janet H. Silversteinb, Shin Amemiyac, Phil Zeitlerd and Georgeanna J Klingensmithe abDivision of Endocrinology, Department of Pediatrics, University of Florida College of Medicine, Gainesville, FL, USA; cDivision of Endocrinology, Department of Pediatrics, Saitama Medical University, Saitama, Japan; dDivision of Endocrinology, Department of Pediatrics, The Children’s Hospital, University of Colorado Denver, Aurora, CO, USA; eDepartment of Pediatrics, The Children’s Hospital and Barbara Davis Center, University of Colorado Denver, Aurora, CO, USA. Corresponding author: Professor Emeritus Arlen L Rosenbloom Division of Endocrinology Department of Pediatrics, University of Florida College of Medicine, 1701 SW 16th Avenue Gainesville, FL 32608 USA. e-mail: rosenal@peds.ufl.edu

Cow's Milk and Insulin-Dependent Diabetes Mellitus

Insulin-dependent diabetes mellitus (IDDM) is a lifelong affliction that affects large numbers of children and adults worldwide. 1 At least 1 in 300 Americans will ultimately develop the disease. Despite advances in insulin purity and delivery, ease of home blood glucose monitoring, and the encouraging results of the Diabetes Control and Complications Trial, 2 IDDM is still associated with an unacceptably high morbidity and mortality. Thus, IDDM is a huge financial burden to affected individuals and their families as well as to society. The total cost of diabetes in the United States currently exceeds $100 billion per year, with a disproportionately large share accounted for by the 10% to 15% of patients with IDDM. 3 Therefore, research aimed at the prevention of IDDM is imperative. The identification and elimination of possible causative agents of the disease would have profound influence on the increasing worldwide incidence of IDDM. Some contend that

Design of insulin analogues for meal-related therapy

The human insulin in replacement therapy has a hexameric structure. Hexamerization of the insulin molecule facilitates biosynthesis and β-cell storage of insulin, but is unnecessary for biologic activity and appears to contribute to delayed absorption of exogenous insulin from the subcutis. Insulin analogues with reduced self-association that are produced through recombinant DNA techniques have been shown to have in vivo activity comparable to that of human insulin and absorption kinetics characterized by higher and more constant rates of disappearance from the subcutaneous injection site. In preliminary studies in patients receiving insulin therapy, monomeric insulin analogues have been found to provide glycemic control in the postprandial period that is at least equivalent to that of human insulin. Findings in these studies suggest that the use of such analogues may provide meal-related insulin effects closer to those observed in the physiologic state by limiting excessive postprandial glucose excursions and decreasing the risk of late hypoglycemia. Banting and Best revolutionized diabetes therapy 70 years ago with the extraction of insulin from animal pancreas glands ( J Lab Clin Med 7:464–472, 1922). Since that time, many refinements of the therapeutic properties of pharmaceutical preparations of the hormone have been introduced. Until recently, however, such advances have been limited to improvements in insulin purity, insulin species, and adjustment of the composition of the vehicle with respect to auxiliary substances and other additives. With the advent of recombinant DNA techniques, it has become possible to optimize the insulin molecule itself for purposes of replacement therapy. A primary goal of such efforts has been the development of insulin analogues with a reduced tendency to self-association, a property of native human insulin that delays absorption of the hormone when exogenously administered. An overview of these efforts and results of early studies with such analogues is presented.

THE SOLUBILITY CURVE AND THE PURITY OF INSULIN

THE SOLUBILITY CURVE AND THE PURITY OF INSULIN