Telemedicine: insulin pump controlled via the Global System for Mobile Communications (GSM).

In the future, the delivery of drugs using telemetric techniques will become more and more important. In the present investigations an experimental insulin pump has been developed which is remote-controlled via a computer program and the Global System for Mobile Communications (GSM). The commands for pump control are transferred in encrypted form via the Short Message Service (SMS). The pump can be programmed in advance for a time period of 24 h. An integrated sensor gives exact information about the number of steps executed by the stepping motor which is controlling the drug release. Model experiments show that there is almost no delay between sending the control SMS and execution of the commands by the pump.

Compressed collagen sponges as gastroretentive dosage forms: in vitro and in vivo studies.

The objective of the present investigations was to develop oblong tablets which expand after contact with gastrointestinal fluids within a few minutes to a length of 4-6 cm and which should remain in the stomach for a prolonged period of time due to their size. The tablets were prepared from riboflavin-containing collagen sponges using a computer controlled single punch tablet machine. The collagen material was compressed to oblong tablets with dimensions of 3.5 mm x 9 mm x 18 mm. In vitro investigations were carried out to characterise drug release. The model drug riboflavin was released from the collagen tablets over 12h. The gastrointestinal retention time of the new dosage form was indirectly estimated by determining the duration of riboflavin excretion after oral intake of the tablet. A crossover in vivo study with 12 healthy male and female subjects was performed. The renal excretion of riboflavin was measured after oral administration of collagen tablets and small sustained release hydrocolloid tablets as reference preparation. The amount of riboflavin excreted into the urine was enhanced after administration of the expanding collagen tablets in comparison with the hydrocolloid tablets. The differences were statistically significant after 5, 6, 8, 9, 10 and 12 h.

Nanoparticles in plant extracts: influence of drugs on the formation of nanoparticles and precipitates in black tea infusions.

The influence of the neuroleptics fluphenazine and promethazine on the formation of nanoparticles in aqueous tea infusions was investigated using photon correlation spectroscopy. Formation of nanoparticles and of precipitates was observed in decaffeinated tea and caffeine-containing tea. The amount of drug in the nanoparticle fraction was determined at different starting concentrations using high-performance liquid chromatography. In the case of fluphenazine, between 8 and 30% are assigned to the nanoparticles fraction, in the case of promethazine between 30 and 56%. The concentration of free active principle is reduced by about 99% for fluphenazine or by about 90% for promethazine. A loss of pharmacological activity of the neuroleptics is probable. The addition of promethazine to infusions of caffeine containing tea resulted in the formation of nanoparticles with a small size distribution; their mean size was comparable to the diameter of nanoparticles in pure tea infusions. In the case of fluphenazine the mean particle size grew with increasing concentration. Adding promethazine to infusions of decaffeinated tea resulted in the formation of nanoparticles with a broad size distribution. Two different size classes were formed after addition of fluphenazine. Caffeine and neuroleptics both take part in the formation of nanoparticles in caffeine containing tea. The particles were visualized using scanning electron microscopy. Molecular modelling calculations were performed to investigate probable geometries between neuroleptics and thearubigins.