In this project a LC-MS-method for the analysis of gamma-hydroxybutyrate, gamma-butyrolactone, 1,4-butanediol, amphetamine and methadone was developed. Initially, the efficiency of the ionisation of the analytes was evaluated with respect to the ionisation technique (ESI, APCI and APPI) and the composition of the mobile phase. In the next step a number of different columns was tested in order to find the one with the greatest potential for separation of the substances in question. Using the selected column, the separation was optimised by means of experimental design and the software The Unscrambler 7.8. The parameters studied were the flow rate, the column temperature and the mobile phase composition. The response variables were the resolution between the target compounds and the retention time of the last eluting compound. These experiments showed that, in order to obtain the best ionisation, the mobile phase should consist of 5 mM formic acid in water and acetonitrile. ESI should be used in the positive mode for all analytes except gamma-hydroxybutyrate, for which the negative mode should be applied. The Hypercarb column exhibited superior retention of the analytes and was therefore selected for further optimisation. The dimensions of this column were 2.1 x 50 mm and the particle size 5 μm, connected to a 2.1 x 10 mm precolumn containing the same packing material. The optimum of the flow rate and the column temperature were 250 μl/min and 20 ºC respectively. For the separation of gamma-hydroxybutyrate, gamma-butyrolactone and 1,4-butanediol the mobile phase consisted of 100% water with 5 mM formic acid. Thereafter a gradient, up to 70% acetonitrile with 5 mM formic acid, was used in order to elute amphetamine and methadone. Efforts were also made to find an internal standard for the method. However, none of the compounds tested was found suitable. In order to get the method usable for routine analysis, which is the goal, further work is required. A suitable internal standard needs to be added to the method and thereafter work remains with validation of the method.

<p>In this project a LC-MS-method for the analysis of gamma-hydroxybutyrate, gamma-butyrolactone, 1,4-butanediol, amphetamine and methadone was developed.</p><p>Initially, the efficiency of the ionisation of the analytes was evaluated with respect to the ionisation technique (ESI, APCI and APPI) and the composition of the mobile phase. In the next step a number of different columns was tested in order to find the one with the greatest potential for separation of the substances in question. Using the selected column, the separation was optimised by means of experimental design and the software The Unscrambler 7.8. The parameters studied were the flow rate, the column temperature and the mobile phase composition. The response variables were the resolution between the target compounds and the retention time of the last eluting compound.</p><p>These experiments showed that, in order to obtain the best ionisation, the mobile phase should consist of 5 mM formic acid in water and acetonitrile. ESI should be used in the positive mode for all analytes except gamma-hydroxybutyrate, for which the negative mode should be applied. The Hypercarb column exhibited superior retention of the analytes and was therefore selected for further optimisation. The dimensions of this column were 2.1 x 50 mm and the particle size 5 μm, connected to a 2.1 x 10 mm precolumn containing the same packing material. The optimum of the flow rate and the column temperature were 250 μl/min and 20 ºC respectively. For the separation of gamma-hydroxybutyrate, gamma-butyrolactone and 1,4-butanediol the mobile phase consisted of 100% water with 5 mM formic acid. Thereafter a gradient, up to 70% acetonitrile with 5 mM formic acid, was used in order to elute amphetamine and methadone. Efforts were also made to find an internal standard for the method. However, none of the compounds tested was found suitable.</p><p>In order to get the method usable for routine analysis, which is the goal, further work is required. A suitable internal standard needs to be added to the method and thereafter work remains with validation of the method.</p>

Hyaluronan (HA) is a substance that is commonly used in biomedical applications in the form of hydrogels. One of these biomedical applications is dermatological fillers where HA is cross-linked with 1,4-Butanediol diglycidyl ether (BDDE) to reduce its rapid turnover within tissue. The filler gives a volumetric effect that can fill out wrinkles. This literature study was conducted in collaboration with Galderma to determine if there is research that explores additives to HA hydrogels that give both volumetric and biological effects when applied as filler. Biological effects that improve the skin's appearance and complexion such as a rejuvenation of the skin was preferable. Both polynucleotides and mannitol show great potential to act as additives in injectable hyaluronan hydrogels.  The main effect of polynucleotides (PN) added in hydrogels is that it is collagen stimulating and provides a more natural tissue regeneration. Rheological properties of the filler change with the addition of PN, where elasticity, viscosity and viscoelasticity have been shown to increase. PNs show no toxicity and are considered safe to inject. The study of mannitol has shown that it does not give a volumetric effect after the injected hydrogel has been broken down. What mannitol can help with, is to prolong the life of the hydrogel and reduce the swelling that is a common side effect after an injection. In addition to this, mannitol is a safe substance to inject.