Protein unbound pharmacokinetics of ambroxol in the blood and brains of rats and the interaction of ambroxol with Polygala tenuifolia by multiple microdialysis

Increased brain uptake of pterostilbene loaded folate modified micellar delivery system

Effective chemotherapy for clinical treatment of brain diseases is still lacking due to the poor penetration of the blood-brain barrier (BBB). The aim of this study was to construct a folate modified pterostilbene (Pt) loaded polymeric micellar delivery system (F-Pt/M) with mPEG-PCL as carrier material to aim at penetrating the BBB for brain tissue targeting via receptor-mediated endocytosis. In this study, F-Pt/M was prepared using thin-film hydration method and then optimized by response surface methodology (RSM) with the entrapment efficiency (EE), drug loading (DL) and hydrodynamic diameter (HD) as indexes. The average hydrodynamic diameter and zeta potential of optimal F-Pt/M were 133.2 nm and 24.6 mV, respectively. DL (18.3%) and EE (98.6%) made the solubility of Pt in water about 25 times higher than that of crude Pt. Results of DSC evaluation revealed that drugs were successfully encapsulated inside the polymeric micelles. TEM images showed that homogeneous spherical micellar structures with a narrow size distribution were developed. The release result in vitro showed that F-Pt/M presented sustained release behavior compared to control free Pt solution. Compared to non-targeted Pt/M, F-Pt/M had a significantly higher cytotoxicity against FR-overexpressing A172 cells. In vitro cellular uptake tests illustrated that the micellar delivery system could significantly improve the accumulation of drugs in target cells via receptor-mediated endocytosis. BBB penetration value (P) of F-Pt/M was about 4 folds higher than that of free Pt group. In addition, drug targeting index (DTI) was calculated to determine targeting of F-Pt/M to the brain which was found to be 4.89, implying improved brain targeting was achieved. Hence, the developed F-Pt/M exhibited great potential for delivering more drug molecules across the BBB for the treatment of brain diseases.

A brief review on critical analytical aspects for quantification of ambroxol in biological samples

Ambroxol (AMB) is a member of the expectorant class, widely used as a secreolytic agent in patients to break up secretions. AMB is rapidly and effectively distributed from blood to tissue. The lungs have the highest concentration of AMB; accumulation of AMB in human lung tissue was detected at concentrations 15- to 20-fold greater than those reported in the circulation. Because of its wide range of actions and therapeutic applications may be worth looking into, particularly for respiratory symptoms, antioxidant, anti-inflammatory, influenza, and rhinovirus infections. Though several analytical methodologies have been established and confirmed for the AMB analysis in matrices of pharmaceutical and biological origins, novel sustainable, and economical methods are still to be choice of protocol to increase its sensitivity, reliability, and repeatability. Therefore, the present review offers an overview of critical analytical aspects regarding the HPLC, LC-MS/MS, HPTLC, capillary electrophoresis, spectrophotometry, and electrochemical methods for quantifying AMB in pharmaceutical and biological samples. Furthermore, this review will thoroughly discuss the physicochemical properties, stability, extraction conditions, instrumentation, and operational parameters of the targeted analyte. As a result, for the first time, this review complies with vital background information and an up-to-date interpretation of research undertaken by anticipated methodologies examined and implemented for the pharmaceutical analysis AMB.

Simultaneous toxicokinetics characterization of acrylamide and its primary metabolites using a novel microdialysis isotope-dilution liquid chromatography mass spectrometry method

Acrylamide (AA) is a toxicant in high-temperature processed foods and an animal carcinogen. Upon absorption, AA is metabolized to glycidamide (GA) or conjugates with glutathione (AA-GSH). Important advantages of microdialysis coupled with liquid chromatography-tandem mass spectrometry (MD-LC-MS/MS) include its minimization of potential losses during sample collection, storage and preparation, as well as an improvement in temporal resolution for toxicokinetics (TKs). We aimed to simultaneously study the TKs of AA and products of its primary metabolism using an isotope-dilution (ID) MD-LC-MS/MS method. MD probes implanted into the jugular vein/right atrium of anesthetized Sprague Dawley rats were connected to the ID-LC-MS/MS for continuous monitoring of AA, GA and AA-GSH in the blood every 15 min over 8 h following intraperitoneal AA administration (0.1 mg/kg or 5 mg/kg). AA, GA, and AA-GSH TKs followed linear kinetics: GA AUC/AA AUC = 0.11 and AA-GSH AUC/AA AUC = 0.011 at 5 mg/kg. Elimination half-life (T_e1/2) values were 2.44 ± 0.70, 4.93 ± 2.37 and 3.47 ± 1.47 h for AA, GA and AA-GSH, respectively. GA TKs reached a plateau at 3-6 h, suggesting that metabolic saturation of AA and T_e1/2 values of the analytes were prolonged with AA at 5 mg/kg. Our results demonstrate that oxidation of AA to GA overwhelmed the conjugation of AA with GSH. Our innovative MD-ID-LC-MS/MS method facilitates the simultaneous characterization of multiple TKs associated with toxicants and their active metabolites with excellent temporal resolution to capture metabolic saturation of AA to GA.

High efficiency photocatalytic degradation of Ambroxol over Mn doped TiO2: Experimental designs, identification of transformation products, mineralization and mechanism

Ambroxol (AMB) is a drug commonly used for chronic bronchitis prevention. Once released in surface water, this recalcitrant chemical becomes a hazardous pollutant. Here, we investigated the ability of 1% Mn-doped TiO₂ (Mn-TiO₂) to mineralize AMB by photocatalysis. We studied the morphology, and the physical and electrochemical properties of Mn-TiO₂ using X-ray diffraction, Scanning electron microscopy, Transmission electron microscopy, X-ray fluorescence, BET method, UV-visible, and electrochemical study and optimized the AMB degrading experimental conditions through response surface methodology (RSM). Mn-TiO₂ at the dose of 0.625 g·L^-1 allowed the complete photodegradation of AMB (30 ppm) at pH 7 under UVA light irradiation for 30 min while total mineralization in CO₂ (>96%) was achieved after 24 h of irradiation. Mn-TiO₂ was 1.6-time more efficient than TiO₂ Degussa P25. Product studies were also carried out by liquid chromatography coupled to electrospray high resolution mass spectrometry. Twenty-one photodegradation products were detected and identified. In addition, ionic chromatography analyses revealed the release of Br^-, NH₄⁺, and NO₃^- at respectively 97, 63 and 35% of the total Br, and N initially present in AMB. Finally, the reusability of the photocatalyst was also tested. After four cycles, the almost complete photodegradation of AMB was achieved showing that Mn-TiO₂ was highly stable. This work brings new physical characteristics on Mn-TiO₂ photocatalyst. Moreover, it is the first study investigating the photocatalytic degradation of recalcitrant AMB drug.