Brain Pharmacokinetic Studies Research Articles

Amoxapine-Loaded Solid Lipid Nanoparticles with Superior Preclinical Pharmacokinetics for Better Brain Delivery: LC-MS/MS and GC-MS Analysis.

The tricyclic antidepressant amoxapine (AMX) has been reported for a rapid onset of action compared to other cyclic antidepressants. It has very low solubility and bioavailability due to first-pass metabolism. Therefore, we planned to develop solid lipid nanoparticles (SLNs) of AMX using a single emulsification method to increase its solubility and bioavailability. HPLC and LC-MS/MS methods were developed further to quantify AMX in the formulation, plasma, and brain tissue samples. The formulation was studied for entrapment efficiency, loading, and in vitro drug release. Particle size and ζ potential analyses, AFM, SEM, TEM, DSC, and XRD were used for further characterization. In vivo oral pharmacokinetic and brain pharmacokinetic studies were performed using Wistar rats. The entrapment and loading efficiencies of AMX in SLNs were 85.8 ± 3.42 and 4.5 ± 0.45%, respectively. The developed formulation had a mean particle size of 151.5 ± 7.02 nm and a polydispersity index of 0.40 ± 0.11. DSC and XRD results indicated that AMX was incorporated into the nanocarrier system in an amorphous form. SEM, TEM, and AFM studies of AMX-SLNs confirmed the particles' spherical shape and nanoscale size. AMX solubility increased by approx. 2.67 times compared to the pure drug. The developed LC-MS/MS method was successfully applied to the oral and brain pharmacokinetic study of AMX-loaded SLNs in rats. Oral bioavailability was enhanced 1.6 times compared to the pure drug. The peak plasma concentrations of pure AMX and AMX-SLNs were 617.4 ± 137.4 and 1043.5 ± 150.2 (ng/mL), respectively. AMX-SLNs showed more than 5.8 times brain concentration compared to the pure drug. Based on the findings, it appears that utilizing a solid lipid nanoparticle carrier to transport AMX can be a highly effective delivery method with improved pharmacokinetic properties in the brain. This approach may prove valuable for future antidepressant treatment.

Development and In Vitro-Ex Vivo Evaluation of Novel Polymeric Nasal Donepezil Films for Potential Use in Alzheimer's Disease Using Experimental Design.

The objective and novelty of the present study is the development and optimization of innovative nasal film of Donepezil hydrochloride (DH) for potential use in Alzheimer’s disease. Hydroxypropyl-methyl-cellulose E50 (factor A) nasal films, with Polyethylene glycol 400 as plasticizer (factor B), and Methyl-β-Cyclodextrin, as permeation enhancer (factor C), were prepared and characterized in vitro and ex vivo. An experimental design was used to determine the effects of the selected factors on permeation profile of DH through rabbit nasal mucosa (response 1), and on film flexibility/foldability (response 2). A face centered central composite design with three levels was applied and 17 experiments were performed in triplicate. The prepared films exhibited good uniformity of DH content (90.0 ± 1.6%–99.8 ± 4.9%) and thickness (19.6 ± 1.9–170.8 ± 11.5 μm), storage stability characteristics, and % residual humidity (<3%), as well as favourable swelling and mucoadhesive properties. Response surface methodology determined the optimum composition for flexible nasal film with maximized DH permeation. All selected factors interacted with each other and the effect of these interactions on responses is strongly related to the factor’s concentration ratios. Based on these encouraging results, in vivo serum and brain pharmacokinetic study of the optimized nasal film, in comparison to DH oral administration, is ongoing in an animal model.

Design and evaluation of thermo-responsive nasal in situ gelling system dispersed with piribedil loaded lecithin-chitosan hybrid nanoparticles for improved brain availability

Piribedil (PBD) is a compound that has shown efficacy in clinical trials to treat motor and non-motor symptoms of Parkinson's disease. However, drug delivery issues like low oral bioavailability, high dosing frequency (3–5 tablets/day), gastrointestinal side-effects reduced the clinical use of PBD. In this work, we have developed lecithin-chitosan hybrid nanoparticles (PBD-LCNs) to improve the direct nose to brain uptake of PBD. PBD-LCNs were optimized using hybrid design approach based on DoE. The mean particle size and drug loading of PBD-LCNs were 147 nm, and 12%, respectively. The PBD-LCNs showed good stability and were found to be nearly spherical in shape. Further, the optimized LCNs were loaded in methylcellulose thermo-responsive in situ gel (PBD-LCN-ISG) to overcome rapid mucociliary clearance upon intranasal administration. Plasma and brain pharmacokinetic studies in rats showed that PBD-LCN-ISG increased the relative bioavailability of PBD in brain (AUCbrain) by about 6.4-folds and reduced the (Cmax)plasma by 3.7-folds when compared to plain intranasal suspension of PBD (PBD-Susp). Further, PBD-Susp showed limited direct nose to brain uptake with DTP values less than 0, while the optimized PBD-LCNs showed DTP value of 56% indicating efficient direct nose to brain uptake. Overall, the development of nanoformulations significantly improved the direct nose to brain uptake of PBD.This article is part of the special Issue on ‘Stress, Addiction and Plasticity'.

Improved brain pharmacokinetics following intranasal administration of N,N,N-trimethyl chitosan tailored mucoadhesive NLCs

ABSTRACTHere we report the development of tristearin-based nanostructured-lipid carriers (NLCs) which were further surface-modified with mucoadhesive N,N,N-trimethyl chitosan (TMC) to form mucoadhesive nanostructured-lipid carriers (mNLCs). The NLCs were loaded with high partitioning ropinirole-dextran sulphate (ROPI-DS) nanoplex. NLCs were optimised using Box-Behnken experimental design. Obtaining controlled drug release with prolonged residence on the nasal mucosa for treating Parkinson’s disease (PD) is a major objective of the present investigation. Enhanced brain targetability and improved therapeutic efficacy are the additional objective of this study. Lyophilised NLCs and mNLCs were characterised in solid state by FTIR, DSC, XRD, and HR-TEM analysis. The bioadhesive strength of mNLCs was observed to be 13.3-folds greater compared to NLCs. Plasma and brain pharmacokinetic studies in mice model demonstrated the potential of mNLCs in nose-to-brain drug delivery via olfactory pathway. If investigated for behavioural and neurotoxicity studies clinically, a commercial formulation for patient looks feasible.

Design, synthesis and biological evaluation of a series of CNS penetrant HDAC inhibitors structurally derived from amyloid-\u03b2 probes

To develop novel CNS penetrant HDAC inhibitors, a new series of HDAC inhibitors having benzoheterocycle were designed, synthesized, and biologically evaluated. Among the synthesized compounds, benzothiazole derivative 9b exhibited a remarkable anti-proliferative activity (GI50 = 2.01 μM) against SH-SY5Y cancer cell line in a dose and time-dependent manner, better than the reference drug SAHA (GI50 = 2.90 μM). Moreover, compound 9b effectively promoted the accumulation of acetylated Histone H3 and α-tubulin through inhibition of HDAC1 and HDAC6 enzymes, respectively. HDAC enzyme assay also confirmed that compound 9b efficiently inhibited HDAC1 and HDAC6 isoforms with IC50 values of 84.9 nM and 95.9 nM. Furthermore, compound 9b inhibited colony formation capacity of SH-SY5Y cells, which is considered a hallmark of cell carcinogenesis and metastatic potential. The theoretical prediction, in vitro PAMPA-BBB assay, and in vivo brain pharmacokinetic studies confirmed that compound 9b had much higher BBB permeability than SAHA. In silico docking study demonstrated that compound 9b fitted in the substrate binding pocket of HDAC1 and HDAC6. Taken together, compound 9b provided a novel scaffold for developing CNS penetrant HDAC inhibitors and therapeutic potential for CNS-related diseases.

Poloxamer-407 thickened lipid colloidal system of agomelatine for brain targeting: Characterization, brain pharmacokinetic study and behavioral study on Wistar rats

The current study was designed to enhance the brain bioavailability and to extract maximum therapeutic benefit from a novel antidepressant drug, agomelatine. For this purpose, a thermoresponsive in situ gel was prepared by dissolving 20% w/v of Poloxamer-407 in agomelatine containing nanoemulsion. To impart mucoadhesive property, 0.5% w/v concentration of chitosan was ensured in the final formulation, named as Ago-NE-gel+0.5%chitosan. The gelling point and mucoadhesive strength of Ago-NE-gel+0.5%chitosan were found to be 28 ± 1 °C, and 6246.27 dynes/cm2 respectively. The size of free micelles of Poloxamer-407 was recorded graphically at 18.43 ± 0.95 nm whereas the size of sterically stabilized Ago-NE was observed at 142.58 ± 4.21 nm. The viscosity and pH of Ago-NE-gel+0.5%chitosan were found to be 2439 ± 23 cP (at 35 ± 1 °C temperature) and 5.8 ± 0.2 respectively. The developed formulation was found safe on nasal mucosa during the toxicity study. CLSM based brain distribution study suggested that Ago-NE-gel+0.5%chitosan is more competent to deliver the drug into the brain as compared to agomelatine-suspension. After intranasal administration of Ago-NE-gel+0.5%chitosan in Wistar rats, the AUC0-8h in brain and plasma were found to be 1418.591 ± 71.87 and 473.901 ± 32.42 ng.h/ml respectively. The hypothesis conceived at the beginning of this research work was delivered as 2.82 folds enhanced bioavailability of agomelatine in the brain. The behavioral studies confirmed that the antidepressant activity of agomelatine can be improved by loading the drug into a mucoadhesive-nanoemulsion-gel system followed by its intranasal administration.

Comparative brain pharmacokinetic study of Jiaotai pills in normal and insomnic rats using brain microdialysis combinated with LC–MS/MS

ObjectiveTo compare the brain pharmacokinetics of five protoberberine-type alkaloids (i.e. berberine, palmatine, coptisine, epiberberine, and jatrorrhizine), which were the main bioactive constituents of Jiaotai Pills (JTP), in normal and insomnic rats orally administrated with JTP. MethodsThe detection was conducted by a fully validated liquid chromatography-tandem mass spectrometry combinated with brain microdialysis method. Brain microdialysis probes were inserted into the hippocampus of rats. JTP extracts were administrated intragastrically and then brain microdialysates were collected at 30 min time intervals for 10 h. The separation of the five protoberberine-type alkaloids was carried out on a BDS Hypersil C18 column using a mobile phase consisting of acetonitrile and water (containing 5 mmol ammonium acetate adjusted to pH 5.0) within 4 min. The quantification was performed by multiple reaction monitoring with the transitions of m/z 336.0-320.1 for berberine, m/z 352.0-336.1 for palmatine, m/z 338.0-322.1 for jatrorrhizine, m/z 336.0-320.1 for epiberberine, m/z 320.0-292.1 for coptisine and m/z 356.4-192.1 for IS. ResultsThe lower limit of quantification for five protoberberine-type alkaloids was 0.05 ng/mL. Linearity, accuracy, precision, stability and matrix effect of five analytes were all satisfactory. Five protoberberine-type alkaloids were quickly distributed in the brain. Moreover, significant differences in the principal pharmacokinetic parameters such as AUC and T1/2 of the analytes were observed between two groups. ConclusionThe LC-MS/MS method combinated with microdialysis is useful in the brain pharmacokinetic study of five protoberberine-type alkaloids. The results indicated that the rates of analytes absorption in insomnic rats were significantly higher than those in normal rats. Besides, the protoberberine-type alkaloids could bring a direct effect on the neuron in the hippocampus.

Determination of the neuropharmacological drug nodakenin in rat plasma and brain tissues by liquid chromatography tandem mass spectrometry: Application to pharmacokinetic studies.

A rapid and sensitive liquid chromatography tandem mass spectrometry detection using selected reaction monitoring in positive ionization mode was developed and validated for the quantification of nodakenin in rat plasma and brain. Pareruptorin A was used as internal standard. A single step liquid-liquid extraction was used for plasma and brain sample preparation. The method was validated with respect to selectivity, precision, accuracy, linearity, limit of quantification, recovery, matrix effect and stability. Lower limit of quantification of nodakenin was 2.0 ng/mL in plasma and brain tissue homogenates. Linear calibration curves were obtained over concentration ranges of 2.0-1000 ng/mL in plasma and brain tissue homogenates for nodakenin. Intra-day and inter-day precisions (relative standard deviation, RSD) were <15% in both biological media. This assay was successfully applied to plasma and brain pharmacokinetic studies of nodakenin in rats after intravenous administration.

Determination of IMM-H004, a novel neuroprotective agent, in rat plasma and brain tissue by liquid chromatography-tandem mass spectrometry.

A rapid and sensitive liquid chromatography-tandem mass spectrometry method for determination of IMM-H004, a novel neuroprotective agent, in rat plasma and brain was developed. Plasma and brain tissue homogenate samples containing IMM-H004 and propranolol (internal standard, IS) were prepared by using a direct protein precipitation of acetonitrile. Separation was carried out in Zorbax SB-C18 column at a flow rate of 0.3mL/min utilizing acetonitrile/water as mobile phases which contain 0.5% formic acid (v/v). Triple quadrupole mass spectrometer was used for detection with selective reaction monitoring. The mass transition ion-pairs were 305→248 for IMM-H004 and 260→183 for IS in positive ion mode. The linear ranges of IMM-H004 were 5-1000ng/mL in plasma and 1-200ng/mL in brain tissue homogenate. The intra- and inter-day precisions were within ±14.9% for analyte in both matrices (±17.0% at the lowest limit of quantification level), while the deviation of assay accuracy was within ±12.9%. No obvious matrix effect was observed. The recovery of the analyte was higher than 85.3%. IMM-H004 was stable during the whole analytic process. The method was applied successfully to the plasma and brain pharmacokinetic study of IMM-H004 in rats after a single intravenous administration.

Study on recovery and its influencing factors of ferulic acid and tetramethylpyrazine in cerebral microdialysis probe

To establish a method for detecting microdialysis recovery of tetramethylpyrazine (TMP) and ferulic acid (FA) and investigating the influencing factors, providing the basis for further in vivo microdialysis experiments. The concentration of FA and TMP in dialysates were determined by high pressure liquid chromatography ( HPLC) and probe recovery were calculated respectively. The influence of the flow rates, medium concentration, temperature and in vivo probe stability on the recovery of FA and TMP were investigated by using concentration difference method (incremental method and decrement method). The recovery obtained by incremental method were similar to by decrement method. The in vitro recovery rate of FA and TMP decreased with the increase of 1-2.5 μL min(-1), and increased obviously with the temperature of 25-42 degrees C under the same conditions. The concentration of FA and TMP had no obvious effect on the probe recovery under the same flow rate. In addition, the recovery of TMP and FA remained stable and showed similar trends under the condition of four concentration cycles, indicating that the intra day reproducibility of the concentration difference method was good. The recovery of brain microdialysis probes in vivo 8 h maintained a relatively stable, but certain differences existed between different brain microdialysis probes, demonstrating that each probe was required for recovery correction in vivo experiment. Microdialysis sampling can be used for the local brain pharmacokinetic study of FA and TMP, and retrodialysis method can be used in probe recovery of FA and TMP in vivo.