oxytetracycline--anhydrous and propionic-acid

This study was carried out to evaluate the potential antibacterial and immunomodulatory effects of the dietary acidifier propionic acid (PA) when given alone or in combination with oxytetracycline (OTC) on Nile tilapia (Oreochromis niloticus). Apparently healthy O. niloticus (n = 240; 52 ± 3.75 g) were randomly allocated into four equal groups (n = 60/group): control group fed a basal diet alone and the other three groups fed basal diets supplemented with either PA (200 mg /kg of diet, PA group) or OTC (500 mg/kg of diet, OTC group) alone or in combination (PA + OTC group). Each group was subdivided into two subgroups (n = 30/subgroup, each subgroup had triplicate of 10 fish); subgroup (A) was used to evaluate the antibacterial effects with the aforementioned 2 weeks feeding regime, and subgroup (B) was used to evaluate the immunomodulatory effects against Aeromonas hydrophila infection with similar 2 weeks feeding regime. Among the four groups, PA + OTC group showed the highest significant (p < 0.0001) antibacterial activity as indicated by widest inhibition zones against A. hydrophila and lowest total gastrointestinal bacterial counts. Additionally, this group had the best immunomodulatory effect as noticed by a significant (p < 0.05) increase in total serum protein, globulin, IgM, phagocytic activity and index, lysosome activity, and significant (p < 0.05) upregulation in the expression levels of immunity-related genes (MHC I, MHC IIA, MHC IIB, Tlr7, IgM heavy chain, TNFα, and IL1β) in head-kidney. Notably, the combined dietary PA and OTC improved the hematological parameters and reduced the oxidative damage of hepatopancreas and head-kidney induced by OTC. This data suggests dietary PA as potential adjuvant to OTC in O. niloticus diets to get maximal antibacterial and immunomodulatory effects.

Topics: Aeromonas hydrophila; Animal Feed; Animals; Anti-Bacterial Agents; Cichlids; Diet; Dietary Supplements; Fish Diseases; Gene Expression Regulation; Gram-Negative Bacterial Infections; Immunologic Factors; Kidney; Liver; Oxytetracycline; Phagocytosis; Propionates

The objective of this study was to determine the chemical stability of tetracycline and oxytetracycline hydro-chlorides in reverse micelles. Their reverse micellar solutions were prepared using cetyltrimethylammonium bromide, water and ethyl formate. The aqueous solutions of the tetracycline antibiotics were also prepared for comparison. The reverse micellar and aqueous solutions were stored at 37 degrees C. Samples were analyzed by high performance liquid chromatography. When evaluation was performed on an aqueous tetracycline HCl solution, its half-life was estimated to be 329 h. Its chemical stability was not improved after being dissolved in the reverse micelles, and a similar half-life of 330 h was observed. However, there were noticeable differences between the two systems in terms of degradation kinetics and degradation byproducts. On the other hand, oxytetracycline HCl was unstable in water so that its half-life was only 34 h. Very interestingly, pronounced improvement in stability was attained with the reverse micellar system: upon dissolving in the reverse micelles, its half-life was increased to 2402 h. There were also marked differences in degradation patterns and mechanisms of oxytetracycline HCl in water and the reverse micelles. Our study indicates that the reverse micellar system has potential applications in solubilizing and stabilizing oxytetracycline HCl, thereby contributing to the development of its dosage forms.

Topics: Cetrimonium; Cetrimonium Compounds; Chromatography, High Pressure Liquid; Drug Stability; Micelles; Oxytetracycline; Propionates; Solubility; Tetracyclines; Water