Pharmacokinetic Investigations Research Articles

A simple and sensitive high-performance liquid chromatographic method combined with fluorescence detection for bioanalysis of scopoletin in rat plasma: Application to a pharmacokinetic study.

Scopoletin, a coumarin class natural phytoalexin, is present in medicinal plants such as noni (Morinda citrifolia). It exhibits diverse pharmacological properties, including antioxidant, anti-hyperuricemic, and anti-inflammatory effects. The objective of this study was to develop a novel HPLC-fluorescence (HPLC-FL) method for the quantitative analysis of scopoletin in the plasma and to investigate its pharmacokinetics in rats. Sample preparation involved a methanol-based protein precipitation method, and chromatographic separation was conducted using a C18 column with an isocratic mobile phase composed of water and acetonitrile containing 0.1% trifluoroacetic acid. The eluent was detected using an FL detector set to optimized excitation/emission wavelengths of 337/453 nm. Method validation encompassed assessments of selectivity, linearity (1-500 ng/mL), precision, accuracy, recovery, matrix effect, and stability in accordance with the prevailing Food and Drug Administration (FDA) guidelines. The developed method was successfully applied for pharmacokineticstudy in rats. To the best of our knowledge, this study is the first application of a simple and sensitive HPLC-FL method for the quantification of scopoletin in a pharmacokinetic study. This method offers a promising alternative for preclinical pharmacokinetic investigations with appropriate modifications and validations and holds potential for clinical applications.

Preparation and in vivo and ex vivo studies of sirolimus nano-in-situ gel ophthalmic formulation

Sirolimus (SR) is a macrolide with antifungal and antitumor immunosuppressant properties, classified as a selective inhibitor of mammalian target of rapamycin (mTOR). In this study, an ionic in situ gel of SR (SR-SUS-ISG) was formulated using gellan gum, exhibiting stability regardless of temperature and pH variations, causing minimal irritation. Harnessing the physiological conditions of the eye, SR-SUS-ISG underwent gelation upon contact with ions, increasing drug viscosity and prolonging retention on the ocular surface. Concurrently, SR-SUS-ISG displayed favorable shear dilution properties, reducing viscosity at ambient temperature, enhancing fluidity, and facilitating convenient packaging and transport. Biocompatibility assessments on both human corneal epithelial cells and rabbit eyes demonstrated that SR-SUS-ISG could well be tolerated. Pharmacokinetic investigations in rabbit ocular aqueous humor revealed sustained release, improved corneal penetration, and enhanced bioavailability. Additionally, in a rat corneal alkali burn model, SR-SUS-ISG exhibited inhibitory effects on corneal neovascularization, associated with decreased levels of the inflammatory factors VEGF and MMPs. These findings suggested that SR-SUS-ISG held promise as an effective ocular drug delivery system.Graphical

Determination of mitomycin C in rat plasma by liquid chromatography-tandem mass spectrometry and its application for determining pharmacokinetics in rat

To develop the liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for measuring mitomycin C in rat plasma, samples were processed using solid-phase extraction, with the internal standard being carbamazepine. A reversed phased C18 column was utilized for the LC-MS/MS study, and mobile phases consisting of 0.1 % formic acid in acetonitrile and water were injected into it at a rate of 0.3 mL/min. Multiple reaction monitoring in positive-ion mode with precursor-product ion pairs 335.3 → 242.3 (mitomycin C) and 237.1 → 194.1 (carbamazepine) was employed to quantify the compounds. The linear range in plasma was found to be 10–4000 ng/mL (r2 = 0.992). The inter-batch and intra-batch precision were <14.3 % (LLOQ: 14.7 %) and 13.4 % (LLOQ: 16.1 %), respectively. The recovery and the matrix effect of mitomycin C in plasma were 113 % and 111 %, respectively. Mitomycin C was stable under the conditions of this assay method. In the end, this approach proved effective in a pharmacokinetic investigation with the intravenous and oral administration of mitomycin C to rats.

CYP3A4-associated food drug interactions: The impact of combined intake of alprazolam with cranberry and pomegranate juice treating anxiety caused by kidney stones

Nephrolithiasis is a common disease and incurs a significant burden on the health care system globally. Patients with kidney stones can be treated with natural remedy such as cranberry, pomegranate, and grape juice. Patients with kidney stone experience anxiety and insomnia as a result of the pain caused by the stones. As a result, physicians may prescribe anxiolytics to treat anxiety, among which alprazolam is a commonly prescribed medication. Meanwhile, cranberry and pomegranate juice are prescribed by many herbal specialists for the treatment of renal calculi. The enzyme CYP3A4 primarily metabolizes alprazolam, while fruit juices such as cranberry and pomegranate juices are potent inhibitors of CYP3A4. Therefore, there could be a drug-food interaction between alprazolam and cranberry and pomegranate juices when consumed concomitantly. A detailed pharmacodynamic and pharmacokinetic investigation is required to ascertain the food-drug interaction between alprazolam, cranberry, and pomegranate juice to avoid the possible toxicity of alprazolam. This review article provides insights about the possible CYP3A4-associated drug interactions between alprazolam and juices of cranberry and pomegranate, for the safe and effective usage of alprazolam in treating anxiety disorders caused by kidney stones.

GC-MS method for simultaneous determination and pharmacokinetic investigation of five volatile components in rat plasma after oral administration of the essential oil extract of Pogostemoncablin

Pogostemon cablin (PC) is a traditional Chinese medicine (TCM) and food as well as an important essential oil plant in China. PC essential oil exerts pharmacological effects such as anti-inflammatory, anti-oxidant, anti-platelet, anti-thrombotic, and anti-depressant. This study established a reliable and sensitive gas chromatography-mass spectrometry (GC-MS) method for the simultaneous determination of the pharmacokinetics of patchouli alcohol, β-elemene, β-caryophyllene, caryophyllene oxide, and farnesol in the plasma of rats after oral administration of PC essential oil extract. Using ethyl acetate to prepare the plasma samples, and p-menthone was used as the internal standard (IS). An HP5-MS column (0.25 μm × 0.25 mm × 30 m) was used for chromatographic separation, and detection was performed in selected ion monitoring (SIM) mode. The accuracies of intra-day and inter-day for all analytes displayed a range of −6.7 %–9.2 %, with precision below 12.5 %. Extraction recoveries for analytes ranged from 74.0 to 106.4 % and matrix effects ranged from 92.4 to 106.9 %. Stability results have demonstrated that the relative standard deviations (RSD) of analytes were below 12.1 %. Therefore, the developed GC-MS method successfully evaluated the pharmacokinetics of five volatile components in PC essential oil extract administered orally to rats.

Cubosome-based Corticosteroidal Drug Delivery System for Sustained Ocular Delivery: A Pharmacokinetic Investigation

Cubosome-based Corticosteroidal Drug Delivery System for Sustained Ocular Delivery: A Pharmacokinetic Investigation

Fiber optic-based integrated system for in vivo multiscale pharmacokinetic monitoring.

This paper presents the development of a fiber-optic-based fluorescence detection system for multi-scale monitoring of drug distribution in living animals. The integrated system utilized dual laser sources at the wavelengths of 488 nm and 650 nm and three photomultiplier channels for multi-color fluorescence detection. The emission spectra of fluorescent substances were tracked using the time-resolved fluorescence spectroscopy module to continuously monitor their blood kinetics. The fiber bundle, consisting of 30,000 optic filaments, was designed for wide-field mesoscopic imaging of the drug's interactions within organs. The inclusion of a gradient refractive index (GRIN) lens within the setup enabled fluorescence confocal laser scanning microscopy to visualize the drug distribution at the cellular level. The system performance was verified by imaging hepatic and renal tissues in mice using cadmium telluride quantum dots (CdTe QDs) and R3. By acquiring multi-level images and real-time data, our integrated system underscores its potential as a potent tool for drug assessment, specifically within the realms of pharmacokinetic and pharmacodynamic investigations.

Validation and Application of a Dried Blood Spot Amoxicillin Assay

AbstractDried blood spot (DBS) antibiotic assays can facilitate pharmacokinetic (PK) investigations in situations where venous blood sampling is logistically and/or ethically challenging. The aim of this study was to establish, validate and demonstrate the application of a DBS amoxicillin assay for PK studies in vulnerable populations. The matrix effect, process efficiency (84–104%) and recovery (85–110%) of the liquid chromatography–mass spectrometry (LC–MS/MS) assay for amoxicillin in DBS was determined at 1, 10 and 100 µg/mL, and three different haematocrits. Thermal stability studies of amoxicillin in DBS were performed and a bridging study comprising 26 paired plasma and DBS samples was conducted in four healthy individuals. The limits of detection and quantification were 0.02 and 0.05 µg/mL for plasma and DBS amoxicillin assays, respectively. Accuracy and interday precision of amoxicillin in DBS (0.1–100 µg/mL) were 88–103% and 4.5–9.2%, respectively. At room temperature (22 °C) and 4 °C, amoxicillin was stable in DBS for ≈4 and 26 h, respectively. There was no degradation of amoxicillin in DBS at −20 °C for &gt; 6 months. When comparing DBS and plasma collected from healthy volunteers, the slope of the Deming regression was 0.74. Amoxicillin CL/F estimates from DBS and plasma concentration data were 40.8 and 30.7 L/h/70 kg, respectively; V/F was 43.2 and 37.4 L/70 kg, respectively. In conclusion, amoxicillin can be reliably assayed from DBS in research studies but may have limited application in therapeutic drug monitoring. Due to poor stability at room temperature, amoxicillin DBS samples should be promptly dried and placed in frozen storage.

Plant-derived bioactive compounds for the inhibition of biofilm formation: a comprehensive review.

Biofilm formation is a widespread phenomenon that impacts different fields, including the food industry, agriculture, health care and the environment. Accordingly, there is a serious need for new methods of managing the problem of biofilm formation. Natural products have historically been a rich source of varied compounds with a wide variety of biological functions, including antibiofilm agents. In this review, we critically highlight and discuss the recent progress in understanding the antibiofilm effects of several bioactive compounds isolated from different plants, and in elucidating the underlying mechanisms of action and the factors influencing their adhesion. The literature shows that bioactive compounds have promising antibiofilm potential against both Gram-negative and Gram-positive bacterial and fungal strains, via several mechanisms of action, such as suppressing the formation of the polymer matrix, limiting O2 consumption, inhibiting microbial DNA replication, decreasing hydrophobicity of cell surfaces and blocking the quorum sensing network. This antibiofilm activity is influenced by several environmental factors, such as nutritional cues, pH values, O2 availability and temperature. This review demonstrates that several bioactive compounds could mitigate the problem of biofilm production. However, toxicological assessment and pharmacokinetic investigations of these molecules are strongly required to validate their safety.

Discovery of Novel Cholinesterase Inhibitors Easily Crossing the Blood-Brain Barrier via Structure-Property Relationship Investigation: Methylenedioxy-Cinnamicamide Containing Tertiary Amine Side Chain.

In the present investigation, a series of dimethoxy or methylenedioxy substituted-cinnamamide derivatives containing tertiary amine moiety (N. N-Dimethyl, N, N-diethyl, Pyrrolidine, Piperidine, Morpholine) were synthesized and evaluated for cholinesterase inhibition and blood-brain barrier (BBB) permeability. Although their chemical structures are similar, their biological activities exhibit diversity. The results showed that all compounds except for those containing morpholine group exhibited moderate to potent acetylcholinesterase inhibition. Preliminary screening of BBB permeability shows that methylenedioxy substituted compounds have better brain permeability than the others. Compound 10c, containing methylenedioxy and pyrrolidine side chain, showed a better acetylcholinesterase inhibition (IC50: 1.52±0.19 μmol/L) and good blood-brain barrier permeability. Further pharmacokinetic investigation of compound 10c using ultra high performance liquid chromatography-mass/mass spectrometry (UPLC-MS/MS) in mice showed that compound 10c in brain tissue reached its peak concentration (857.72±93.56 ng/g) after dosing 30 min. Its half-life in the serum is 331 min (5.52 h), and the CBrain/CSerum at various sampling points is ranged from 1.65 to 4.71(Mean: 2.76) within 24 hours. This investigation provides valuable information on the chemistry and pharmacological diversity of cinnamic acid derivatives and may be beneficial for the discovery of central nervous system drugs.

Abstract PO3-19-09: SERENA-1: Results from a Phase 1 study (Parts I/J) testing the next-generation oral selective estrogen receptor degrader (SERD) camizestrant (AZD9833) in combination with capivasertib in women with ER+, HER2 advanced breast cancer

Abstract Background: SERENA-1 (NCT03616587) is a Phase 1, multi-part, open-label study of camizestrant in women with ER+/HER2− advanced breast cancer. Data for camizestrant as monotherapy and in combination with palbociclib or abemaciclib have been presented previously.1–3 Here we present data from parts I and J (dose ranging and expansion, respectively), which examined camizestrant in combination with the pan-AKT inhibitor capivasertib. Methods: The primary objective was to determine the safety and tolerability of camizestrant 75 mg once daily (QD) in combination with capivasertib 400 mg twice daily (BID; intermittent: 4 days on, 3 days off). Secondary objectives included investigation of anti-tumor response and pharmacokinetics (PK). Participants were women of any menopausal status (pre-menopausal women received concomitant ovarian function suppression). Prior treatment with an endocrine therapy (ET) in the advanced setting was required with no limit on the number of lines of prior ET. Prior treatment with ≤2 lines of chemotherapy in the advanced setting was permitted. Prior treatment with CDK4/6 inhibitors (CDK4/6i) and/or fulvestrant was also permitted. Results: As of 21 March 2023, 29 patients had received camizestrant in combination with capivasertib. Patients were heavily pretreated in the advanced setting (48% prior chemotherapy, 90% prior CDK4/6i, 55% prior fulvestrant) and 72% had visceral metastases. The safety and tolerability profile of the combination of camizestrant and capivasertib was broadly consistent with that of each drug individually.4,5 In the 29 patients, adverse events considered related to camizestrant and/or capivasertib in &amp;gt;15% of patients (%; n grade 1/n Grade 2/n Grade &amp;gt;3) included diarrhea (66%; 14/2/3), visual effects (62%; all Grade 1), bradycardia (34%; all Grade 1), nausea (34%; 6/4/0), fatigue (21%; 4/2/0) maculopapular rash (17%; 0/3/2) and aspartate aminotransferase increased (17%; 3/0/2). The PK and safety data indicated no clinically relevant drug–drug interactions between camizestrant and capivasertib. The objective response rate was 29.6% (8/27), the clinical benefit rate at 24 weeks was 51.7% (15/29), and median progression–free survival was 8.3 months. Overall, 12 patients had a detectable ESR1 mutation (ESR1m) at baseline (Cycle 1, Day 1) and an evaluable Cycle 2, Day 1 (C2D1) result; of these, ESR1m was reduced by &amp;gt;50% at C2D1 in 91.7% of patients (11/12), including 66.7% (8/12) of patients where ESR1m was cleared. Conclusions: Camizestrant 75 mg QD in combination with capivasertib 400 mg BID was well tolerated and associated with encouraging clinical and pharmacodynamic activity. These data support further evaluation of this combination in women with ER+/HER2− advanced breast cancer.

In silico modeling, development, characterization, in-vitro cytotoxicity, pharmacokinetic, and toxicological studies of folate-receptor targeted micelles containing cisplatin and upconversion nanoparticles for lung cancer therapy

Folate receptor α (FRα) is one of the best motifs to recognize lung cancer, therefore it can be utilized for targeted delivery of therapeutic agents in lung cancer therapy. Herein, we developed folate-receptor-targeted micelles (CPTT-FA) for the co-delivery of cisplatin (CDDP) and upconversion nanoparticles (UCNP) as theranostics for lung cancer therapy. Initially, the binding affinity of FRα (4MK6) was studied, resulting in good docking scores of −7.6 towards 4MK6 by stimulating PI3K inhibition in lung cancer cells. Micelles, fabricated using the solvent-casting technique, exhibited favorable characteristics, including an average size ranging from 80 to 190 nm with a narrow size distribution and spherical morphology. The zeta potential of −29.4 mV indicates stability and potential for targeted delivery. The drug encapsulation efficiency of the micelles was high, ranging from 70 % to 90 %. In vitro, release studies demonstrated an initial burst release of 40 % within 4 h, the release rate was controlled up to 72 h in PBS at pH 6.8. Afterthat, IC50 of the CPTT-FA micelles was found to be 11.6-fold lower than Ciszest-50. Heamolysis study has proven the greater biocompatibility of CPTT-FA. Pharmacokinetic investigations exhibited a significant enhancement with a three-fold increase in the area under the concentration-time curve (AUC0-t) and a 3.7-fold extension in half-life (t1/2). CDDP resistance in lung cancer presents a promising avenue for targeted therapy using UCNP, addressing challenges posed by FRα-positive cases and improving prognosis. Further clinical investigations are needed to validate the effectiveness and safety of this approach before its widespread implementation.

Acute severe renal failure in a patient receiving apixaban: a case report

Because there is little clinical experience with apixaban in patients with severe renal impairment and non-valvular atrial fibrillation, the European Medicines Agency does not advise using it to prevent strokes in these patients. However, only a small number of pharmacokinetic and pharmacodynamic investigations showed how crucially different elimination pathways contribute to the clearance of apixaban. A 74-year-old male patient who was receiving apixaban treatment for stroke prevention in atrial fibrillation was referred to our hospital because of acute severe renal failure brought on by dehydration and abnormally elevated apixaban plasma levels. The patient was treated only with intravenous fluid therapy; serum creatinine recovered slowly over the course of six days, but plasma apixaban levels recovered quickly. No bleeding events have been recorded. Our experience demonstrates the safety profile of apixaban in cases of severe renal failure, but it also emphasizes the need for more research to confirm this evidence.

Novel pH-sensitive triptolide-loaded micelles: a potential approach to increase anti-tumor activity of the diterpenoid epoxide

Tripterygium wilfordii Hook F, a traditional medicine in China has bioactive but toxic triptolide (TP, a diterpenoid triepoxide) as its main active constituents. The applications of TP are hampered by its prominent toxicity and low solubility in water. In this study, a safe pH-sensitive material [methoxy polyethylene glycol (mPEG)- adipic dihydrazide (ADH)] was synthesized and loaded with TP to form pH-sensitive polymeric micelles, thereby improving the safety and solubility of TP, as well as providing a theoretical basis for the wide application of TP. The mPEG-ADH/TP micelles were characterized by a series of indicators [namely entrapment efficiency (EE), critical micellar concentration (CMC), electrokinetic potential, stability, polydispersed index (PDI), and particle size]. Also, we ascertained the in vitro release of TP from mPEG-ADH/TP micelles along with pharmacokinetic investigations in vivo. Besides, we evaluated the cytotoxicity of mPEG-ADH/TP micelles against A549 cells, HCT116 cells, and HaCat cells and further conducted in vivo toxicity studies in rats. The TP-loaded mPEG-ADH micelles had smaller sized particles (48.3 nm), excellent PDI (0.142), stable property and higher EE (89.87%). Importantly, the TP in the mPEG-ADH/TP micelles was almost completely released at acidic pH (pH 5.0), while the drug was released slowly and sparingly at physiological pH (pH 7.4). The results suggest the release of TP from mPEG-ADH/TP micelles was sensitive to pH, which could facilitate targeting of the drug into intra-cellularly low pH endosomes and lysosomes as well as enhance cytotoxicity in cancer tissues. Moreover, mPEG-ADH/TP micelles exhibited excellent proliferation inhibition on tumor cells. In addition, the liver injury of rats in the 1 mg/kg dose of mPEG-ADH/TP micelles group was significantly reduced by Hematoxylin–eosin (HE) staining. Taken together, mPEG-ADH/TP micelles could act as a promising alternative to enhance the efficacy of oncologic treatments.

Design, Optimization, and Evaluation of Chitosan-2-mercaptobenzoic Acid as a Dual-functionalized Thiomer

Aims: This study aimed to develop and evaluate mucoadhesive microspheres for the controlled release of zidovudine using a novel dual-functionalized polymer. Background: Mucoadhesive polymers have recently been widely used to prolong the GI residence time and to modulate the release impact of various mucoadhesive dosage forms. In the present study, a recently synthesized chitosan derivative, chitosan-2-mercapto benzoic acid, was used as a mucoadhesive polymer, which was further developed as a dosage form for improving oral bioavailability of zidovudine drug. Objective: The objective of this study is to evaluate the impact of a novel thiolated derivative, chitosan-2-mercaptobenzoic acid, on the oral bioavailability of the drug zidovudine. Methods: The microspheres were prepared using an emulsification crosslinking method with TPP as the crosslinking agent. Techniques such as FTIR, and DSC were employed to analyze the microspheres, along with drug content, entrapment efficiency, dissolution studies, mucoadhesion, ex vivo permeation, and in vivo evaluations. Results: Results from FTIR spectroscopy and DSC analysis revealed no interaction between the drug and polymers. The release kinetics and characterization assessments indicated a zero-order release profile with anomalous and super case-II transport types. Ex vivo permeation studies on goat intestinal mucosa demonstrated enhanced mucoadhesive properties and permeability with the optimized microspheres fabricated using thiomers compared to conventional oral therapy. Pharmacokinetic investigations showed higher zidovudine plasma levels and Cmax with the administration of microspheres, particularly those composed of thiomers. The AUC0-24h values for thiomer microspheres were significantly greater than controls and chitosan microspheres, indicating improved oral bioavailability potential. Conclusion: In conclusion, zidovudine-loaded thiomer-based mucoadhesive microspheres showed promising results with the ability to enhance the drug's oral bioavailability.

A Novel Chitosan-coated Leciplex Loaded with Ambrisentan as a Possible Pulmonary Nanosystem: Optimization, Characterization, and Pharmacokinetics Assessments

The purpose of this research was to formulate, optimize, and characterize ambrisentan chitosan-coated LeciPlex (AMS-CTS-LPX) to increase the therapeutic effectiveness and bioavailability of ambrisentan. A central composite design (CCD) was implemented to assess the impact of various factors on the production of AMS-CTS-LPX and to identify the optimum formulation via the use of Design Expert® software. The assembly of AMS-CTS-LPX was conducted using a single-step process. Subsequently, the optimal formulation was chosen and subjected to further assessments. Further, a comparative pharmacokinetic study was carried out using a rat model. The optimized formulation exhibited an entrapment efficiency of 82.39%, with a diameter of 137.53 nm and a surface charge of +43.65 mV. Additionally, it had a sustained cumulative release of 90.41% after 8 h and showed good stability. The safety of AMS-CTS-LPX administered intratracheally was confirmed by in vivo histopathological studies. The pharmacokinetic investigations revealed a 5.6-fold increase in the bioavailability of AMS from the optimal AMS-CTS-LPX formulation compared to the oral AMS solution. Collectively, the results of the current study suggest that CTS-LPX may be beneficial as a pulmonary nanosystem for the administration of AMS.

Preclinical pharmacokinetic investigation of the bioavailability and skin distribution of HY-072808 ointment, a novel drug candidate for the treatment of atopic dermatitis, in minipigs by a newly LC-MS/MS method

HY-072808 is a novel phosphodiesterase 4 inhibitor clinically used for topical atopic dermatitis treatment. Cytochrome P450 enzymes are involved in transforming it into major metabolite ZZ-24. An efficient UPLC–MS/MS method was established to detect HY-072808 and ZZ-24 in plasma and skin tissues of minipigs.One-step protein precipitation was performed with acetonitrile. Subsequently, elution was served with a methanol and water gradient containing 0.1% formic acid for 3.5 min. The plasma and skin tissue concentrations of HY-072808 and ZZ-24 showed good linearity from 0.200 to 200 ng/mL.The experimental minipigs exhibited low systemic exposure and bioavailability of 3.1–7.6% after transdermal application of 1–4% HY-072808 ointment. Multiple topical administrations over seven consecutive days showed a minor accumulation in systemic exposure, with accumulation factors of 2.3 and 4.0 for HY-072808 and ZZ-24, respectively.The distribution of HY-072808 ointment among different cortical layers in minipigs was studied for the first time. Following transdermal application of 2% HY-072808 ointment, the concentration in plasma and skin tissues in the order of epidermis > dermis > subcutaneous tissue ≈ subcutaneous muscle ≈ plasma; at 48 h after the administration, the epidermis and dermis still had a high concentration of the drug.

Green LC-MS/MS method for in-vivo pharmacokinetics of mirabegron-encapsulated nanostructured lipid carriers in rat plasma: Integrating white analytical chemistry and analytical quality by design approach

Mirabegron (MBG) stands as the top choice for managing overactive bladder, yet its limited aqueous solubility and low bioavailability pose significant challenges. To overcome these hurdles, the objective was to develop and characterize nanostructured lipid carriers (NLCs) for mirabegron, facilitating its controlled release for overactive bladder treatment through the Quality by Design (QbD) approach. The literature showcases several analytical techniques for mirabegron quantification in pharmaceutical formulations and biological fluids, yet most employ toxic organic solvents in their mobile phases, posing environmental risks and threats to aquatic life. To address this concern, a green liquid chromatographic-tandem mass spectrometry method was developed for in-vivo pharmacokinetic assessment of mirabegron-loaded NLCs in rat plasma, utilizing safe organic solvents. The method's development embraced the principles of analytical QbD, aiming to curtail organic waste generation during sample analysis. Rigorous validation was conducted in accordance with the International Council for Harmonization (ICH) Q2 (R1) and M10 guidelines. The developed method found application in both in-vitro drug release kinetics and in-vivo pharmacokinetic investigations of mirabegron-loaded NLCs. Its performance was assessed using the principles of green and white analytical chemistry through a comparative study with existing analytical techniques. The proposed method's exceptional sensitivity, robustness, and eco-friendliness in mirabegron estimation were highlighted by the results. In conclusion, this proposed green analytical approach not only provides a reliable means of mirabegron analysis but also aligns with sustainable practices by minimizing environmental impact and promoting the principles of green and white analytical chemistry and analytical quality by design.

Investigation of Antibody Pharmacokinetics in the Brain Following Intra-CNS Administration and Development of PBPK Model to Characterize the Data.

Despite the promising potential of direct central nervous system (CNS) antibody administration to enhance brain exposure, there remains a significant gap in understanding the disposition of antibodies following different intra-CNS injection routes. To bridge this knowledge gap, this study quantitatively investigated the brain pharmacokinetics (PK) of antibodies following intra-CNS administration. The microdialysis samples from the striatum (ST), cerebrospinal fluid (CSF) samples through cisterna magna (CM) puncture, plasma, and brain homogenate samples were collected to characterize the pharmacokinetics (PK) profiles of a non-targeting antibody, trastuzumab, following intracerebroventricular (ICV), intracisternal (ICM), and intrastriatal (IST) administration. For a comprehensive analysis, these intra-CNS injection datasets were juxtaposed against our previously acquired intravenous (IV) injection data obtained under analogous experimental conditions. Our findings highlighted that direct CSF injections, either through ICV or ICM, resulted in ~ 5-6-fold higher interstitial fluid (ISF) drug exposure than IV administration. Additionally, the low bioavailability observed following IST administration indicates the existence of a local degradation process for antibody elimination in the brain ISF along with the ISF bulk flow. The study further refined a physiologically based pharmacokinetic (PBPK) model based on new observations by adding the perivascular compartments, oscillated CSF flow, and the nonspecific uptake and degradation of antibodies by brain parenchymal cells. The updated model can well characterize the antibody PK following systemic and intra-CNS administration. Thus, our research offers quantitative insight into antibody brain disposition pathways and paves the way for determining optimal dosing and administration strategies for antibodies targeting CNS disorders.

Guinea Pig Round Window Membrane Explantation for Ex Vivo Studies.

Efficient and minimally invasive drug delivery to the inner ear is a significant challenge. The round window membrane (RWM), being one of the few entry points to the inner ear, has become a vital focus of investigation. However, due to the complexities of isolating the RWM, our understanding of its pharmacokinetics remains limited. The RWM comprises three distinct layers: the outer epithelium, the middle connective tissue layer, and the inner epithelial layer, each potentially possessing unique delivery properties. Current models for investigating transport across the RWM utilize in vivo animal models or ex vivo RWM models which rely on cell cultures or membrane fragments. Guinea pigs serve as a validated preclinical model for the investigation of drug pharmacokinetics within the inner ear and are an important animal model for the translational development of delivery vehicles to the cochlea. In this study, we describe an approach for explantation of a guinea pig RWM with surrounding cochlear bone for benchtop drug delivery experiments. This method allows for preservation of native RWM architecture and may provide a more realistic representation of barriers to transport than current benchtop models.