Demeclocycline

The syndrome of inappropriate antidiuretic hormone secretion (SIADH) can occur following traumatic brain injury (TBI), but is usually transient. There are very few case reports describing chronic SIADH and all resolved within 12 months, except for one case complicated by meningo-encephalitis. Persistent symptomatic hyponatremia due to chronic SIADH was present for 4 years following a TBI in a previously well 32-year-old man. Hyponatremia consistent with SIADH initially occurred in the immediate period following a high-speed motorbike accident in 2010. There were associated complications of post-traumatic amnesia and mild cognitive deficits. Normalization of serum sodium was achieved initially with fluid restriction. However, this was not sustained and he subsequently required a permanent 1.2 l restriction to maintain near normal sodium levels. Multiple episodes of acute symptomatic hyponatremia requiring hospitalization occurred over the following years when he repeatedly stopped the fluid restriction.

AIM: To determine the effect of pH, oxygen levels and ions on tetracycline oxidation and resultant discolouration.

Phosphorus (P) recovery was carried out through struvite precipitation from urines. Human urine, however, contains not only high nutrients for plants, such as P and nitrogen, but also pharmaceuticals and hormones. In this work, effects of magnesium (Mg) dose (in terms of Mg:P ratio) on P recovery efficiency and pharmaceutical amounts contained in struvite were investigated. Batch-scale experiments of synthetic and human urines revealed that struvite precipitation formed more X-shaped crystals with an increased molar ratio of Mg:P, while the amount of pharmaceuticals (tetracycline, demeclocycline, and oxytetracycline) in struvite decreased with an increased molar ratio of Mg:P. The lowest pharmaceutical amounts in struvite were found at the Mg:P ratio of 2:1 from both samples. Moreover, the maximum P recovery efficiency, quantity and purity of struvite were found in the range of 1.21 to 2:1. It indicated that the molar ratio of Mg:P has a significant impact on struvite precipitation in terms of pharmaceutical amounts in struvite; morphology, quantity and purity of struvite; and P recovery.

Tetracyclines (TCs), broad spectrum antibiotics widely used in the prevention and treatment of infectious diseases, are amphoteric molecules containing several ionizable functional groups that exist predominantly as zwitterions at a given pH value. TCs are reported to undergo a wide variety of reactions at different pH values i.e. TCs form to anhydrotetracyclines at low pH, 4-epitetracyclines at pH 3-5 and isotetracyclines at high pH values. The pH-dependent absorbance and emission properties of tetracycline and its 10 analogs (4-epitetracycline, doxycyline, oxytetracycline, chlortetracycline, 4-epichlortetracycline, isochlortetracycline, methacycline, rolitetracycline, minocycline, and demeclocycline) were investigated and reported in this paper. The main focus of the study was on the pH dependent transformation of epichlortetracycline, chlortetracycline and isotetracycline at basic pH. Absorption, emission and time resolved spectroscopy were used to determine the behavior of the three TC derivatives at this condition.