Since its initial discovery in 1922 by Banting and Best, the formulation of an oral insulin delivery system has ever been so troublesome. Unfortunately, insulin is indispensable in the treatment of diabetes mellitus, which affects approximately 350 million people worldwide. Various factors contribute to the peptide being such a persistently difficult hormone to be used in an oral formulation. The gastrointestinal tract is home to various protein digestive enzymes such as pepsins in the stomach and trypsin, chymotrypsin and carboxypeptidases in the small intestine, which digests insulin. Also the physical barrier of the gastrointestinal tract, i.e. the columnar epithelial layer which lines the tract, is a tightly bound collection of cells with minimal leakage and is thus a sound barrier for the absorption of peptides and hormones. The aim of this study is to determine whether a dosage form for insulin, entrapped in Pheroid™ vesicles and -micro sponges, can overcome these barriers and successfully deliver insulin at the site of action resulting in a significant therapeutic response. Initial phases of the study consisted of the manufacturing of Pheroid™ vesicles and - microsponges, entrapment of flourescein-isothiocyanate labelled insulin (FITC-insulin) into the Pheroid™. The Pheroid™-insulin complex was analysed with confocal laser scanning microscopy (CLSC) to determine drug loading. In vivo experiment in Sprague - Dawley rats were done where blood glucose levels as well as insulin blood levels were monitored after administration of different Pheroid insulin formulations. Firstly a standard reference was set by subcutaneous injection of insulin (0.5 IU/kg) in rats followed by a comparative study where administration to the stomach, colon and ileum (50.0 IUlkg insulin) were compared by means of blood insulin levels and therapeutic effect between the control and Pheroid™ complexes (Pheroid™ vesicles and microsponges). Each study was done by means of direct injection into the stomach, ileum or colon through which the insulin in saline (control) or insulin-Pheroid™ complex was administered. Nasal administration of 8.0 and 12.0 IU/kg insulin in saline (control) or insulin-Pheroid™ complex was done in the right nostril of Sprague - Dawley rats. Blood samples were taken from the artery carotis communis by means of an inserted cannula. Blood samples were taken just before administration and then at 5, 10, 15, 30, 60, 120 and 180 minutes after administration. Blood glucose levels were measured just after every blood sample was taken and plasma insulin levels were determined with a human insulin specific radioimmunoassay. The results were compared to the reference as well as the control to determine relative bioavailability. Through the results obtained it was discovered that in comparison with the various parts of the or tract, the ileum showed undoubtedly to be the best area of absorption where Pheroid™ vesicles revealed a peak 42.0 % lowering in blood glucose levels after 60 minutes and a peak plasma concentration of 244.0 /uID/ml after 5 minutes together with an 18.7 % lowering in blood glucose levels after just 5 minutes. After nasal administration of Pheroid™ microsponges (8.0 ID/kg insulin) a remarkable lowered blood glucose level of 19.2 % after 10 minutes and 36.5 % after 30 minutes as well as a peak plasma insulin level of220.2 /lID/ml after 3 hours was observed. Insulin entrapped in Pheroid™ microsponges administered at 12.0 ID/kg showed a maximum blood glucose lowering effect of72.4 % after 3 hours with a peak plasma level of 154.8 uID/ml also after 3 hours, thus showing a long acting effect. In conclusion, the delivery system based on Pheroid™ technology shows a sufficient therapeutic effect for insulin and is therefore promising for further in vivo evaluation and ultimately for medicinal use to patients suffering from diabetes mellitus. / Thesis (Ph.D. (Pharmaceutics))--North-West University, Potchefstroom Campus, 2009.

Thesis (Ph.D. (Pharmacy))--North-West University, Potchefstroom Campus, 2008.

Since its initial discovery in 1922 by Banting and Best, the formulation of an oral insulin delivery system has ever been so troublesome. Unfortunately, insulin is indispensable in the treatment of diabetes mellitus, which affects approximately 350 million people worldwide. Various factors contribute to the peptide being such a persistently difficult hormone to be used in an oral formulation. The gastrointestinal tract is home to various protein digestive enzymes such as pepsins in the stomach and trypsin, chymotrypsin and carboxypeptidases in the small intestine, which digests insulin. Also the physical barrier of the gastrointestinal tract, i.e. the columnar epithelial layer which lines the tract, is a tightly bound collection of cells with minimal leakage and is thus a sound barrier for the absorption of peptides and hormones. The aim of this study is to determine whether a dosage form for insulin, entrapped in Pheroid™ vesicles and -micro sponges, can overcome these barriers and successfully deliver insulin at the site of action resulting in a significant therapeutic response. Initial phases of the study consisted of the manufacturing of Pheroid™ vesicles and - microsponges, entrapment of flourescein-isothiocyanate labelled insulin (FITC-insulin) into the Pheroid™. The Pheroid™-insulin complex was analysed with confocal laser scanning microscopy (CLSC) to determine drug loading. In vivo experiment in Sprague - Dawley rats were done where blood glucose levels as well as insulin blood levels were monitored after administration of different Pheroid insulin formulations. Firstly a standard reference was set by subcutaneous injection of insulin (0.5 IU/kg) in rats followed by a comparative study where administration to the stomach, colon and ileum (50.0 IUlkg insulin) were compared by means of blood insulin levels and therapeutic effect between the control and Pheroid™ complexes (Pheroid™ vesicles and microsponges). Each study was done by means of direct injection into the stomach, ileum or colon through which the insulin in saline (control) or insulin-Pheroid™ complex was administered. Nasal administration of 8.0 and 12.0 IU/kg insulin in saline (control) or insulin-Pheroid™ complex was done in the right nostril of Sprague - Dawley rats. Blood samples were taken from the artery carotis communis by means of an inserted cannula. Blood samples were taken just before administration and then at 5, 10, 15, 30, 60, 120 and 180 minutes after administration. Blood glucose levels were measured just after every blood sample was taken and plasma insulin levels were determined with a human insulin specific radioimmunoassay. The results were compared to the reference as well as the control to determine relative bioavailability. Through the results obtained it was discovered that in comparison with the various parts of the or tract, the ileum showed undoubtedly to be the best area of absorption where Pheroid™ vesicles revealed a peak 42.0 % lowering in blood glucose levels after 60 minutes and a peak plasma concentration of 244.0 /uID/ml after 5 minutes together with an 18.7 % lowering in blood glucose levels after just 5 minutes. After nasal administration of Pheroid™ microsponges (8.0 ID/kg insulin) a remarkable lowered blood glucose level of 19.2 % after 10 minutes and 36.5 % after 30 minutes as well as a peak plasma insulin level of220.2 /lID/ml after 3 hours was observed. Insulin entrapped in Pheroid™ microsponges administered at 12.0 ID/kg showed a maximum blood glucose lowering effect of72.4 % after 3 hours with a peak plasma level of 154.8 uID/ml also after 3 hours, thus showing a long acting effect. In conclusion, the delivery system based on Pheroid™ technology shows a sufficient therapeutic effect for insulin and is therefore promising for further in vivo evaluation and ultimately for medicinal use to patients suffering from diabetes mellitus. / Thesis (Ph.D. (Pharmaceutics))--North-West University, Potchefstroom Campus, 2009.

Thesis (M.S.)--University of Michigan, 1992.

Thesis (M.S.)--University of Michigan, 1964.

Thesis (M.S.)--University of Michigan, 1992.

Thesis (M.S.)--University of Michigan, 1964.

Thesis (doctoral)--Erasmus Universiteit Rotterdam, 2005. / "CHER C publication series"--T.p. verso. Includes bibliographical references (p. 268-280).

A literatura mundial jà vem demonstrando, hà bastante tempo, que a assistÃncia mÃdica em obstetrÃcia trouxe benefÃcios incalculÃveis aos partos distÃcicos. Por outro lado, as tecnologias utilizadas para a assistÃncia ao parto normal, a nÃvel hospitalar, vÃm sendo questionada e, intervenÃÃes, como a episiotomia, o uso abusivo de ocitÃcicos para abreviar o perÃodo de dilataÃÃo, e a posiÃÃo horizontal (deitada) da parturiente, durante o perÃodo expulsivo do parto, estÃo sendo analisadas e criticadas por um largo nÃmero de pesquisadores. O presente estudo visou testar a hipÃtese de que a assistÃncia ao parto normal na posiÃÃo vertical (sentada), durante o perÃodo expulsivo, seria mais apropriada, por ser fisiolÃgica. AlÃm disso, nÃo se usou o procedimento da episiotomia e observou-se a influÃncia da sucÃÃo do mamilo materno pelo RN no tempo de delivramento e perdas sanguÃneas, sem o uso de ocitÃcicos. A diferenÃa mÃdia de 3,4 minutos em favor da menor duraÃÃo do perÃodo expulsivo, para as parturientes que foram assistidas sentadas, merece destaque, apesar da significÃncia do dado estar em seu limiar estatÃstico, ao nÃvel de 95% (p=0,06). A maioria das parturientes delivraram espontaneamente atà 25 minutos depois do parto, nÃo importando se assistidas na vertical, ou na horizontal; as perdas sanguÃneas tambÃm tiveram equivalÃncias estatÃsticas(p=0,52). A sucÃÃo do mamilo materno mostrou alguma influÃncia mas nÃo logrou significÃncia estatÃstica em relaÃÃo a perdas sanguÃneas (p=0,19) e ao tempo de delivramento (vertical: p=0,08; horizontal: p=0,52). Mesmo sem o procedimento da episiotomia, as laceraÃÃes vulvo-perineais se mantiveram em 44,1% e 47,1% para as mulheres que pariram na vertical e horizontal, respectivamente (incidÃncia mais baixa do que os 52,3% que se encontra na literatura), sendo que mais de 80% em ambos os grupos, a laceraÃÃo foi de 1 grau e o restante apenas de 2 grau. NÃo ficou evidenciada qualquer vantagem na posiÃÃo vertical sobre a posiÃÃo horizontal materna durante o perÃodo expulsivo do parto e delivramento, sendo portanto indicado que se permita a livre escolha da parturiente. A abstenÃÃo do uso de ocitÃcicos e de episiotomia nÃo acarretou prejuÃzo Ãs mÃes que pariram, em qualquer das duas posiÃÃes. Assim, os achados do estudo nÃo apontam para a necessidade de intervenÃÃes obstÃtricas de rotina, na assistÃncia ao parto normal; indicando, outrossim, que elas sejam mais criteriosas, evitando-se iatrogenias e promovendo assistÃncia de melhor qualidade e mais humanizada. / Since a long time, world literature has been demonstrating that medical assistance brought large benefits to complications on deliveries. In the other hand, overused obstetric technologies on normal delivery assistance in hospitals are being questioned. Interventions such as episiotomy, the abuse of oxytocic to shorten the dilatation period and the laying down posture imposed to women during labor are being criticized by a large number of researchers. This study intended to find out if the sitting position to assist the second period of womenâs delivery is more appropriate for it is considered physiological. Besides that, no episiotomy has been performed and immediate breastfeeding consequences on blood loss and on the delivery of placenta were observed. The 3.4 minutes difference on favor of the length of time expulsion period to the group of women who delivered on vertical position versus horizontalâs was considered important but not statistic significant (p=0.06). The great majority of mothers has delivered the placenta within the first 25 minutes, regardless they were on the upright (sitting) or neutral (laying down) position. Blood loss was also equivalent on both groups (p=0.52) and breastfeeding did not show any influence on that (p=0.19) and on the time for delivering the placenta (sitting-p=0.08; laying down-p=0.52). The incidence of perineal trauma was 44.1% and 47.0% for women who delivered on vertical and horizontal position, respectively (this incidence was even lower than the 52.3% which is reported on literature). More than 80% of the spontaneous injuries were 1st degree posterior perineal trauma and the rest was just 2nd degree ones, for both groups. It was not evident any advantage of the vertical position over the horizontalâs, during the expulsion period of labor and delivery of placenta. So, mothers could be given the choice in the posture to be assumed during parturition. The absence of oxytocic and episiotomy did not bring any harm to women delivering in any of the two positions. The outcomes do not support medical intervention should be used as routine on normal delivery and for that, those interventions could have a better criteria, avoiding more harm than good and offering a more humanized delivery assistance.

The ability to deliver DNA to target cells creating therapeutic effects remains an important goal in the field of gene therapy. A majority of clinical trials to overcome this issue have utilized viral vectors due to their efficiency at DNA delivery and ability to create high levels of gene expression. However, their inherent toxicity and a several clinical trials leading to patients contracting new diseases from the treatment have greatly hindered the progress of viral gene therapy. Non-viral gene delivery agents have a much better safety profile, but are also much less efficient at delivering DNA, leading to low gene expression. The reason for this low expression is the numerous barriers that must be overcome to achieve gene expression: circulation, tissue specific accumulation, internalization, release of DNA cargo, and nuclear localization. While peptides are currently being improved upon, enhancing binding and the ability to protect DNA, they are still deficient when it comes to tissue specificity. Numerous targeting methods, including the use of lectins, antibodies, aptamers, and peptides, have been designed to deliver molecules to a specific research. Research to incorporate targeting ligands onto non-viral gene delivery vectors is abundant in the literature; however, successful site specific gene delivery has not been achieved. The somatostatin receptor 2 (SSTR2) ligand, octreotide, is a well-researched eight amino acid peptide that has extensive SAR data available. Also, the receptors have been well characterized and octreotide is used clinically in the radioscintigraphy imaging of brain tumors. While well researched, there are unexplored opportunities to utilize octreotide to enhance non-viral gene delivery vectors. The overall scope of this thesis is to develop and synthesize non-viral gene delivery peptides conjugated to octreotide creating receptor mediated targeting of DNA polyplexes to create tissue specific accumulation. Initial experiments indicated that attachment of octreotide to the polycationic peptide WK18 does not inhibit affinity for the SSTR2 receptor. Therefore, peptides were designed and synthesized to attach octreotide onto polyacridine peptide (Acr-Lys)6. Polyplex characteristics were unchanged by the incorporation of octreotide, and exhibited very low genotoxic effects compared to the in vitro gene delivery agent PEI. Competitive binding assays suggested a stoichiometric, ligand, and temperature dependent accumulation of polyplex on SSTR2 expressing cells, but gene expression could not be achieved. The success of (Acr-Lys)6octreotide, led to the synthesis of a di-maleimide-PEG attached to each end by (Acr-Lys4)3Acr-Lys-Cys or Cys-Gly5octreotide in attempts to create distance, and better ligand availability for the receptor, by expressing octreotide away from the polyplex. Testing of this peptide in PEGylated polyplex ad-mixtures verified that separating the DNA binding peptide from octreotide did lead to better inhibition of binding to DAOY cells in a competitive binding study. However, transfection assays with this compound showed background levels of gene expression. Although gene expression was not achieved, the synthetic strategy to create a molecule incorporating a DNA binding peptide, ligand, and PEG to create better ligand presentation to its receptor when incorporated into PEGylated polyplexes is an important step in the design of gene delivery vectors.