Atomic Force Microscopy Studies of Solid Lipid Nanoparticles

Purpose. Solid Lipid Nanoparticles (SLN) are an alternative carrier system for the controlled delivery of drugs. In most cases prednisolone loaded SLN show a biphasic release behaviour. The initial phase is characterised by a fast drug release, which is followed by a sustained drug release over several weeks. Methods. The particles are produced by high pressure homogenisation of a lipid (e.g. compritol, cholesterol) dispersed in an aqueous surfactant solution. In this study atomic force microscopy was used to image the original unaltered shape and surface properties of the particles. The crystallinity of the nanoparticles was investigated by differential scanning calorimetry. Results. The AFM investigations revealed the disc like shape of the particles. From differential scanning calorimetry data it can be concluded that the particle core is in the crystalline state. Additionally it was proven that the particles are surrounded by a soft layer. Conclusions. Thus it is conceivable that the fast initial drug release during in vitro dissolution tests takes place by drug release of the outer non-crystalline layers of the particles. The following sustained drug release can be assigned to the predisolone release of the inner crystalline particle layers.     

Evaluation of contrast markers for CT aspiration biopsy.

Precision percutaneous needle aspiration biopsy under guidance of computed tomography is facilitated by injection of a small amount of contrast material during the biopsy procedure. CT scan immediately after biopsy clearly documents the biopsy site. There was no adverse effect of the contrast agents on the quality of staining or preservation of cellular architecture. To the contrary, the aspirates obtained after contrast injection were generally better preserved and better stained than the control specimens. This may be due to a decrease in drying, with the more fluid aspirates obtained after contrast injection.     

Die substanzpolymerisation von acrylnitril

The bulk polymerization of acrylonitrile for conversions Q 15% was studied by means of an improved dilatometric technique and a new method of evaluation. Starting from the results of the kinetic analysis a novel and simple mechanism for the polymerization is deduced, that is in excellent agreement with the experimental data, as could be shown by integrating the rate-law. Said mechanism can be expressed by the following scheme: and denotes, that beside a polymerization in homogeneous solution, polymer growth alsoproceeds in heterogeneous state, where bimolecular terminations can be neglected. It could be shown further, that induction periods showing up at the beginning of the re-action are not caused by impurities in the monomer, as they were reproducible and dependent of the initial initiator concentration. The following rate constants were calculated resp. estimated for 60°C:      

Über die Möglichkeiten der Diabetesbehandlung mit Biguaniden

Ohne Zusammenfassung     

Untersuchungen zur Frage einer Wechselwirkung von saluretisch wirksamen Thiazidderivaten und Thiamin bei Diabetikern

Zusammenfassung 20 Diabetikern wurde 8 Tage lang Hydrochlorothiazid und über weitere 8 Tage zusätzlich Thiamin verabreicht. Die durch Hydrochlorothiazid signifikant herabgesetzte Glucosetoleranz normalisierte sich nach zusätzlichen Thiamingaben. Die Nüchternwerte des Seruminsulins (IRI) waren unter Thiazidgaben (mit und ohne Thiamin) gegenüber den Ausgangswerten ohne Thiazidbelastung erhöht (p<0,1). Freie Fettsäuren und anorganisches Phosphat im Plasma blieben unverändert. Die erhobenen Befunde sprechen für extrapankreatische Faktoren als Ursache der durch Saluretica verursachten Stoffwechselstörung. Ein Thiamin-Thiazid-Antagonismus könnte nach unseren Versuchsergebnissen ein Faktor im möglicherweise komplex beeinflußten Stoffwechsel von Thiaziddiabetikern sein.

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Summary Twenty diabetics were treated over a period of eight days with hydrochlorothiazide and for other eight days with hydrochlorothiazide and thiamine. The thiazide-induced hyperglycemia was significantly decreased by the additional therapy with thiamine to the original values before hydrochlorothiazide treatment started (p<0,05). The fasting levels of seruminsulin (IRI) after hydrochlorothiazide treatment (with and without thiamine) were somewhat higher than the levels before (p<0,1). Free fatty acids and phosphate in plasma did not change. The results suggest an extrapancreatic mechanism for hydrochlorothiazide-induced hyperglycemia. Antagonistic action of thiamine and thiazide could be an important factor of hydrochlorothiazide influence on carbohydrate metabolism.