Evaluation of direct and indirect photodegradation of mianserin with high-performance liquid chromatography and short-term bioassays.

The widespread use of pharmaceuticals has lead to their detection in surface and ground waters. In the last year antidepressants in particular have shown very high growth dynamics of consumption and numerous research shows that these pharmaceuticals are detected in the environment and even in drinking water. Drugs and their metabolites can be subject to two types of photoreaction, direct and indirect photodegradation. These pharmaceuticals even at low concentration can have adverse effects on aquatic life, and the resulting photoproducts can be more toxic than parents compounds. The aim of this study was to evaluate the direct and indirect photodegradation of mianserin. The kinetics of the process and the identification of photoproducts were investigated by HPLC-PDA and HPLC-MS/MS, respectively. Ecotoxicity of mianserin before and after irradiation was assessed with a battery of assays with bacteria, protozoa and crustacea. The results show that mianserin was not toxic to Vibrio fischeri (Microtox), but its toxicity to protozoan Spirostomum ambiguum (Spirotox) and crustacean Thamnocephalus platyurus (Thamnotoxkit F(™)) was comparable to other antidepressants. On the basis of the results of the toxicity and HPLC before and after irradiation it can be seen that the decrease toxicity of mianserin was related only to a decrease of its concentration. The photoproducts had no impact to toxicity. The direct photodegradation of mianserin was more effective in UV/vis light than vis light. However the presence of humic acid in the indirect photodegradation increases the rate of degradation without regard to the kind of used light.

[Production and assessing release of imipramine and magnesium from tablets]. / Technologia otrzymywania i ocena uwalniania imipraminy i magnezu z tabletek.

BACKGROUND: In the pharmaceutical technology there is a trend to produce tablets composed of several medicinal substances to increase therapeutic effect and reduce the frequency of drug administration. In the literature there are reports concerning pharmacological studies in which a potentiation of the effects has been observed after a co-administration of antidepressant imipramine and magnesium. Currently, there is no formulation on the market comprising imipramine and magnesium, therefore, it was decided to produce uncoated tablets. In order to prepare the tablets by direct compression, it was necessary to select suitable excipients. OBJECTIVES: The aim of the study was to elaborate the composition and to prepare the tablets with imipramine and magnesium, as well as to assess the quality of the tablets by physical characteristics and by the release study of the active substances. MATERIAL AND METHODS: In order to prepare the tablets, compositions of different polymers and other excipients were added. The tablets were produced by direct compression method in a tablet press. Physical properties of the obtained tablets and the release of the active substances into an acidic medium in a paddle apparatus were tested. The contents of imipramine and magnesium were determined by different methods: spectrophotometrically and atomic absorption spectrometry, respectively. RESULTS: The composition of excipients necessary to produce tablets comprising imipramine and magnesium was established. All of prepared tablets were in compliance with the pharmacopoeial requirements. The release tests showed that above 80% of imipramine was released within 20-35 min and 80-76% of magnesium up to 45 min from the composed tablets and one-ingredient tablets, respectively. CONCLUSIONS: The compositions of excipients for tablets consisting of imipramine and magnesium were presented. The active substances were released within 45 min in the acidic medium, and the administration of these substances in the composed tablets did not affect pharmaceutical availability.

High-power laser diodes emitting light above 1100 nm with a small vertical divergence angle of 13 degrees.

Laser diodes with highly strained InGaAs quantum wells, emitting at 1130 nm, embedded in a GaAs waveguide were investigated. This Letter reviews the design of the vertical structure for enclosing high output power in angles smaller than 18 degrees . Example designs were processed to 200 microm stripe-width lasers with an 8-mm-long optical cavity. When these are mounted on C mounts, they give an output power of 38 W under quasi-cw operation from a single emitter.