Background: A low dose of capsaicin and its natural homologs and analogs (capsaicinoids) have shown to prevent development of gastric mucosal damage of alcohol and non-steroid anti-inflammatory drugs. Based on this experimental observation, a drug development program has been initiated to develop per os applicable capsaicin containing drugs to eliminate gastrointestinal damage caused by non-steroid anti-inflammatory drugs. Methods: As a part of this program, a sensitive and selective reverse-phase high-performance liquid chromatography-based method with fluorescence detection has been developed for quantification of capsaicin and dihydrocapsaicin in experimental dog’s plasma. Results: The method was evaluated for a number of validation characteristics (selectivity, repeatability, and intermediate precision, LOD, LOQ, and calibration range). The limit of detection (LOD) was 2 ng/mL and the limit of quantification (LOQ) was 10 ng/mL for both capsaicin and dihydrocapsaicin. The method was used for analysis of capsaicin and dihydrocapsaicin in the plasma samples obtained after per os administration of low doses (0.1, 0.3, and 0.9 mg/kg bw) of Capsaicin Natural (USP 29) to the experimental animals. Conclusions: The obtained results indicated that the administered capsaicinoids did not reach the general circulation.

Hyperglycemia is reported to be associated with oxidative stress. It can result in changes in the activities of drug-metabolizing enzymes and membrane-integrated transporters, which can modify the fate of drugs and other xenobiotics; furthermore, it can result in the formation of non-enzyme catalyzed oxidative metabolites. The present work aimed to investigate how experimental hyperglycemia affects the intestinal and biliary appearance of the oxidative and Phase II metabolites of ibuprofen in rats. In vivo studies were performed by luminal perfusion of 250 μM racemic ibuprofen solution in control and streptozotocin-treated (hyperglycemic) rats. Analysis of the collected intestinal perfusate and bile samples was performed by HPLC-UV and HPLC-MS. No oxidative metabolites could be detected in the perfusate samples. The biliary appearance of ibuprofen, 2-hydroxyibuprofen, ibuprofen glucuronide, hydroxylated ibuprofen glucuronide, and ibuprofen taurate was depressed in the hyperglycemic animals. However, no specific non-enzymatic (hydroxyl radical initiated) hydroxylation product could be detected. Instead, the depression of biliary excretion of ibuprofen and ibuprofen metabolites turned out to be the indicative marker of hyperglycemia. The observed changes impact the pharmacokinetics of drugs administered in hyperglycemic individuals.

Metabolism of xenobiotics can be influenced by a number of factors, among which hyperglycaemia caused by the insufficiency of the glucose metabolism (e.g., diabetes mellitus, impaired glucose tolerance, resistance) should be emphasized. Not only the pathological condition, but the compounds administered as treatment can alter the metabolic profile of certain pharmacons. While the rapid-acting insulin exerts its effect mainly with the acute change of the blood glucose level, the prolonged-acting insulin affects in a more complex way. Because of its simple and well-characterised metabolic profile, the p-nitrophenol (PNP) is a model compound for the investigation of conjugative (glucuronidation and sulfation) transformations. An in vivo experimental study was evaluated to determine the quantities of the forming p – p-nitrophenyl-glucuronide (PNP-G) and p-nitrophenol-sulfate (PNP-S) conjugates in small intestinal perfusate and bile samples in physiologic condition, in experimental diabetes (streptozotocine (STZ) induced), and in compensated diabetes with prolonged–acting insulin. In these investigations, the formed metabolic profile was influenced by the individual effect of the administered insulin.

In this study, a terminological and grammatical survey of essential and fatty oils of plant origin was performed in the selected Austrian, Hungarian, Spanish, and Belgian pharmacopoeias from the 18th to 19th centuries. The Latin-language prescriptions were analysed for their content, sections, and indications, and then translated from Latin into English, and supplemented with the source plants. Oil types were categorised based on their preparation and origin. Most oils belong to essential oils in Ph. Austriaca I–IV, Ph. Belgica, and Ph. Hungarica I (20 in each). Cooked oils are described as having the highest number in Ph. Hispanica (21), while pressed oils are also included in a high ratio in Ph. Hisp. (18) and Ph. Austriaca V (15). At the same time, those from minerals are described only in Ph. Belg. (2) and Ph. Hisp. (5). Latin terms are used in preparation methods, including the most concise descriptions in Ph. Austriaca V and Ph. Hg. I. This comprehensive study provides new linguistic data on the oils of herbs in the selected pharmacopoeias. Studies of essential oils have recently been progressing, and this analysis might help in understanding information from old pharmacopoeias.

Intestinal Absorption and Transformation of the Increased Dose of Paracetamol in Streptozotocin-Induced Diabetic Rats