Pharmacokinetics and bioavailability assessment of Miltefosine in rats using high performance liquid chromatography tandem mass spectrometry

Determining tissue distribution of the oral antileishmanial agent miltefosine: a physiologically-based pharmacokinetic modeling approach

Miltefosine (MTS) is the only approved oral drug for treating leishmaniasis caused by intracellular Leishmania parasites that localize in macrophages of the liver, spleen, skin, bone marrow, and lymph nodes. MTS is extensively distributed in tissues and has prolonged elimination half-lives due to its high plasma protein binding, slow metabolic clearance, and minimal urinary excretion. Thus, understanding and predicting the tissue distribution of MTS help assess therapeutic and toxicologic outcomes of MTS, especially in special populations, e.g., pediatrics. In this study, a whole-body physiologically-based pharmacokinetic (PBPK) model of MTS was built on mice and extrapolated to rats and humans. MTS plasma and tissue concentration data obtained by intravenous and oral administration to mice were fitted simultaneously to estimate model parameters. The resulting high tissue-to-plasma partition coefficient values corroborate extensive distribution in all major organs except the bone marrow. Sensitivity analysis suggests that plasma exposure is most susceptible to changes in fraction unbound in plasma. The murine oral-PBPK model was further validated by assessing overlay of simulations with plasma and tissue profiles obtained from an independent study. Subsequently, the murine PBPK model was extrapolated to rats and humans based on species-specific physiological and drug-related parameters, as well as allometrically scaled parameters. Fold errors for pharmacokinetic parameters were within acceptable range in both extrapolated models, except for a slight underprediction in the human plasma exposure. These animal and human PBPK models are expected to provide reliable estimates of MTS tissue distribution and assist dose regimen optimization in special populations.

Enhanced oral bioavailability of levormeloxifene and raloxifene by nanoemulsion: simultaneous bioanalysis using liquid chromatography-tandem mass spectrometry

Aim & objective: Levormeloxifene (L-ORM) and raloxifene (RAL) are selective estrogen receptor modulators used in the treatment of postmenopausal osteoporosis and breast cancer. Here, we developed and validated a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the simultaneous estimation of both drugs. Materials & methods: A quality-by-design (QbD) approach was used for the optimization of the nanoemulsion, and US FDA guidelines were followed for method validation. Results: Multiple reaction monitoring transitions were used for L-ORM (459.05→98.50), RAL (475.00→112.02) and internal standard (180.10→110.2). Analytes were resolved in a C18 column with 80:20 v/v% acetonitrile (ACN), 0.1% formic acid in triple-distilled water as a mobile phase. The developed method was linear over a concentration range of 1-600 ng/ml. Pharmacokinetic results of free L-ORM-RAL and the L-ORM-RAL nanoemulsion showed Cmax of free L-ORM - 70.65 ± 16.64, free RAL 13.53 ± 2.72, L-ORM nanoemulsion 65.07 ± 14.0 and RAL-nanoemulsion 59.27 ± 17.44 ng/ml. Conclusion: Future findings will contribute to the treatment of postmenopausal osteoporosis and breast cancer using L-ORM and RAL.

Simultaneous estimation of five biomarkers of neuroprotective herb Ashwagandha NMITLI-118R AF1 in rat plasma and brain using LC-ESI-MS/MS: Application to its pharmacokinetic and stability studies

Withania Somnifera (WS) is a popular nutritional supplement in the USA, Europe, and Asia, known for its pharmacological effects on neurological disorders. However, the bioanalytical method development, validation, and pharmacokinetics of WS NMITLI-118R AF1 biomarkers Withanolide A (WLD A), Withanone (WNONE), Withanolide B (WLD B), Withaferin A (WF A), and 12 Deoxywithastramonolide (12 DEOXY) in rats have not been comprehensively explored. This study aimed to develop and validate a sensitive and selective LC-ESI-MS/MS method for these biomarkers in male Sprague Dawley rats plasma and brain matrix. Rats were divided into eight groups, each containing five rats. A plant extract of NMITLI-118R AF1 at 50 mg/kg was orally administered to the rats for in-vivo pharmacokinetic investigation. All the analytes had a linear calibration curve (r2 > 0.999), and intra-day and inter-day precision (%) were found in the range of 2.46 - 13.71% and accuracy were within the acceptable range (±15%). The biomarkers of NMITLI-118R AF1 were found stable in in-vitro plasma and simulated gastro-intestinal fluids. The observed (Cmax) and (Tmax) values for the biomarkers in the systemic circulation were WLD A (5.59 ± 0.34 ng/mL, Tmax 1.00 ± 0.00 h), WNONE (6.28 ± 0.41 ng/mL, Tmax 0.95 ± 0.11 h), WLD B (6.45 ± 2.87 ng/mL, Tmax 0.95 ± 0.11 h), WF A (6.50 ± 0.27 ng/mL, Tmax 1.00 ± 0.00 h), and 12 DEOXY (5.68 ± 0.39 ng/mL, Tmax 1.00 ± 0.00 h). In contrast to the old method, our approach exhibits a lower limit of quantification (LLOQ), shorter run time (less than10 min), and enables the detection of WF A and WNONE in fresh rat plasma by other quantitative analysis of mass spectrometry (m/z) [M]+. Shows high sample volumes for both, larger plasma volumes, costlier sample collection techniques dried blood spot (DBS), more expensive solid phase extraction techniques (SPE) and longer analysis time 14 min. Moreover, our method requires a smaller sample volume 10 µL, offers faster analysis time 4 min, and achieves a higher sensitivity 1 ng/mL. This is the first report of a comprehensive study on in-vitro and in-vivo pharmacokinetics of NMITLI-118R AF1 biomarkers, which may aid in further pre-clinical and clinical trial investigations.

LC-MS/MS method for quantification of raspberry ketone in rat plasma: application to preclinical pharmacokinetic studies

Background: Raspberry ketone (RK), derived from red raspberry fruit (Rubus idaeus, family Rosaceae), is a reported potent antiobesity agent. This study aims to investigate method development, validation, and in vitro and in vivo pharmacokinetics in rats. Materials & methods: LC-MS/MS was used to conduct method development, validation, stability, and oral PK samples of RK in plasma analyses. Results: RK was highly soluble in Tris buffer and stable in gastrointestinal fluids as well as plasma. Rat liver microsomal stability of RK in phase I and II studies was 84.96 ± 2.39 and 69.98 ± 8.69%, respectively, after 60 min. Intestinal permeability was 4.39 ± 1.37 × 10^-5 cm/s. Maximal concentration was 1591.02 ± 64.76 ng/ml, which was achieved after 1 h (time to maximal concentration), and absolute oral bioavailability was 86.28%. Conclusion: Pharmacokinetic data serve as a keystone for preclinical and clinical adjuvant therapy.

Effect of Clindamycin on Intestinal Microbiome and Miltefosine Pharmacology in Hamsters Infected with Leishmania infantum

Visceral leishmaniasis (VL), a vector-borne parasitic disease caused by Leishmania donovani and L. infantum (Kinetoplastida), affects humans and dogs, being fatal unless treated. Miltefosine (MIL) is the only oral medication for VL and is considered a first choice drug when resistance to antimonials is present. Comorbidity and comedication are common in many affected patients but the relationship between microbiome composition, drugs administered and their pharmacology is still unknown. To explore the effect of clindamycin on the intestinal microbiome and the availability and distribution of MIL in target organs, Syrian hamsters (120-140 g) were inoculated with L. infantum (108 promastigotes/animal). Infection was maintained for 16 weeks, and the animals were treated with MIL (7 days, 5 mg/kg/day), clindamycin (1 mg/kg, single dose) + MIL (7 days, 5 mg/kg/day) or kept untreated. Infection was monitored by ELISA and fecal samples (16 wpi, 18 wpi, end point) were analyzed to determine the 16S metagenomic composition (OTUs) of the microbiome. MIL levels were determined by LC-MS/MS in plasma (24 h after the last treatment; end point) and target organs (spleen, liver) (end point). MIL did not significantly affect the composition of intestinal microbiome, but clindamycin provoked a transient albeit significant modification of the relative abundance of 45% of the genera, including Ruminococcaceae UCG-014, Ruminococcus 2; Bacteroides and (Eubacterium) ruminantium group, besides its effect on less abundant phyla and families. Intestinal dysbiosis in the antibiotic-treated animals was associated with significantly lower levels of MIL in plasma, though not in target organs at the end of the experiment. No clear relationship between microbiome composition (OTUs) and pharmacological parameters was found.

Development and validation of an HPLC-MS/MS method for the quantification of the anti-leishmanial drug miltefosine in human skin tissue

Miltefosine is the only oral drug approved for the treatment of various clinical presentations of the neglected parasitic disease leishmaniasis. In cutaneous leishmaniasis and post-kala-azar dermal leishmaniasis, Leishmania parasites reside and multiply in the dermis of the skin. As miltefosine is orally administered and this drug is currently studied for the treatment of these skin-related types of leishmaniasis, there is an urgent need for an accurate assay to determine actual miltefosine levels in human skin tissue to further optimize treatment regimens through target-site pharmacokinetic studies. We describe here the development and validation of a sensitive method to quantify miltefosine in 4-mm human skin biopsies utilizing high-performance liquid chromatography coupled to tandem mass spectrometry. After the skin tissues were homogenized overnight by enzymatic digestion using collagenase A, the skin homogenates were further processed by protein precipitation and phenyl-bonded solid phase extraction. Final extracts were injected onto a Gemini C18 column using alkaline eluent for separation and elution. Detection was performed by positive ion electrospray ionization followed by a quadrupole - linear ion trap mass spectrometer, using deuterated miltefosine as an internal standard. The method was validated over a linear calibration range of 4-1000 ng/mL (r² ≥ 0.9996) using miltefosine spiked digestion solution for calibration and quality control samples. Validation parameters were all within internationally accepted criteria, including intra- and inter-assay accuracies and precisions within± 15% and ≤ 15% (within± 20% and ≤ 20% at the lower limit of quantitation). There was no significant matrix effect of the human skin tissue matrix and the recovery for miltefosine, and internal standard were comparable. Miltefosine in human skin tissue homogenates was stable during the homogenization incubation (37 °C,± 16 h) and after a minimum of 10 days of storage at - 20 °C after the homogenization process. With our assay we could successfully detect miltefosine in skin biopsies from patients with post-kala azar dermal leishmaniasis who were treated with this drug in Bangladesh.

Simultaneous quantification of five biomarkers in ethanolic extract ofCassia occidentalisLinn. stem using liquid chromatography tandem mass spectrometry: application to its pharmacokinetic studies

Cassia occidentalis L. stem extract is used as a purgative, febrifuge, and diuretic, and in the treatment of flu, fever, fracture and bone diseases. Pharmacological studies prove the osteogenic and antiresorptive effects of Cassia occidentalis L. ethanolic extract (COEE), which may be due to apigenin, apigenin-6-C-glucopyranoside, luteolin, 3′,4′,7-trihydroxyflavone and emodin. The objectives of this study was to develop a selective and sensitive LC-MS/MS method and validate for the simultaneous determination of the above five biomarkers in rat plasma after oral administration of COEE at a dose of 500 mg kg⁻¹. The analytes were separated on a Phenomenex Luna C18 column (4.6 × 150 mm, 3.0 μm) with an isocratic mobile phase consisting of methanol-10 mM ammonium acetate buffer (95 : 05, v/v). Run time was for 5.5 min with LLOQ of 1 ng mL⁻¹ for all the analytes. The mass spectrometer was operating in negative ionization mode for quantification of the analytes. The calibration curves were linear (r² > 0.99) for all the analytes. The intra- and inter-day precisions were less than 8.17% and the relative error was between −8.57% and 7.28%. Analytes were rapidly absorbed in the oral pharmacokinetic study. The biomarkers were stable in simulated gastric and intestinal fluids but underwent metabolism in rat liver microsomes. This is the first report on in vivo oral pharmacokinetics and in vitro stability studies of osteogenic compounds present in COEE. These results will be helpful for further understanding of pharmacodynamic behaviour of COEE and the bioanalytical method will be useful for further preclinical/clinical trials.

Liquid chromatography tandem mass spectrometry was used to develop a bioanalytical method for simultaneous quantification of five biomarkers of Cassia occidentalis L. ethanolic extract to use in oral pharmacokinetics and in vitro stability studies.

LC-ESI-MS/MS assay development and validation of a novel antidiabetic peptide PSTi8 in mice plasma using SPE: An application to pharmacokinetics

PSTi8 is a 21 amino acid pancreastatin inhibitory peptide that demonstrated potent antidiabetic activity in insulin resistant rodent models. The goal of the current work is to establish and validate the LC-ESI-MS/MS bioanalytical assay of PSTi8 in mice plasma in order to unveil its pharmacokinetic (PK) behaviour for the first time. The MS detection of PSTi8 and diprotin A (internal standard, IS) was conducted with Q1/Q3 SRM transitions at 607.80 ([M+4 H]⁴⁺)/771.20 and 342.20/229.10, respectively using positive ESI. Phenomenex Aqua 5μ 125A (250 × 4.6 mm) column was utilized to separate PSTi8 and IS with a mobile phase consists of MeOH-0.1 % formic acid (1:1, v/v) using 0.4 mL/min flow rate. SPE using medium anion exchange cartridge (Oasis MAX) was used for the extraction of analyte and IS from the mice plasma and the extraction recovery was found to be >55 %. PSTi8 displayed good linearity across the 5-1000 ng/mL concentrations range. The intra- and inter- day accuracy was observed between 99.44-110.20 % and 99.66-110.93 %, respectively. The intra- and inter- day precision was observed between 2.61-4.03 % and 2.90-7.16 %, respectively. The intra-day and inter-day accuracy and precision data was within the 100 ± 15 % nominal values recommended by the United States Food and Drug Administration bioanalytical guidance. The LC-MS/MS assay was validated effectively to investigate the PSTi8 plasma concentrations following intravenous and intraperitoneal PK studies in mice. The absolute bioavailability of PSTi8 was 52.74 ± 13.50 %.

Pharmacokinetic and Bioavailability Studies of Embelin after Intravenous and Oral Administration to Rats

Embelin exhibits the broad bioactivities such as antitumor, antifertility, antidiabetic, anti-inflammatory, antioxidant, anticonvulsant, anxiolytic, antimicrobial, and hepatoprotective activity. In order to further understand the pharmacokinetic characteristics and oral bioavailability of embelin in vivo, the concentration of embelin in rat plasma was determined by a sensitive high-performance liquid chromatography with diode array detector (HPLC-DAD). The preparation of samples was accomplished by a simple precipitating protein with methanol. Emodin was selected as the internal standard (IS). Embelin and IS were completely separated on an analytical column (Extend-C18, 4.6 × 250 mm, 5 μm) using 0.1% phosphoric acid in methanol and 0.1% phosphoric acid in aqueous solution (90:10, v/v) as the mobile phase. The lower limit of quantification was 0.15 μg/mL. Oral bioavailability of embelin was 30.2 ± 11.9%. This study could provide the information about pharmacokinetics and oral bioavailability of embelin, which was useful to assess the clinic efficacy and safety and promote further development of embelin.

Carbomer gel bearing methotrexate loaded lipid nanocontainers shows improved topical delivery intended for effective management of psoriasis

The present investigation reports the evaluation of potential use of Carbomer gel bearing methotrexate loaded nanostructured lipid carriers for topical application of methotrexate for possible therapy of psoriasis in comparison to solid lipid nanoparticles. These were evaluated for various parameters such as particle size, surface charge, entrapment efficiency, shape and surface morphology, thermal analysis, in-vitro drug release through skin (Franz diffusion cell) and drug deposition study, fluorescence microscopy, particle-skin interaction study, skin-irritation testing and storage stability. The formulation (NLC₅) showed the best entrapment efficiency (62.72 ± 0.94%) while SLN showed only 26.84 ± 0.64% with particle size of 221 ± 14nm and 212 ± 11nm, respectively. Skin permeation study of MTX loaded SLN and NLC₅ hydrogels showed prolonged drug release up to 24 h. The skin drug deposition study showed the greatest deposition of drug enriched NLC₅ hydrogel (28.8%) when compared to plain drug enriched hydrogel (11.4%) and drug enriched SLN hydrogel (18.6%). Fluorescence microscopy suggested the localization effect of these lipid based systems to deeper skin region. The primary skin irritation studies indicated that MTX loaded SLN or NLC₅ hydrogels resulted no erythema. It can be concluded that NLC represents a promising particulate carrier having prolonged drug release, improved skin permeation.

Evaluation of oral pharmacokinetics, in vitro metabolism, blood partitioning and plasma protein binding of novel antidiabetic agent, S009-0629 in rats

S009-0629 [methyl-8-(methylthio)-2-phenyl-6-p-tolyl-4,5-dihydro-2H-benzo[e]indazole-9-carboxylate] is a novel antidiabetic agent with PTP1B inhibitory activity. In this study, we have investigated the in vitro metabolic stability, plasma protein binding, blood partitioning, and oral pharmacokinetic study of S009-0629 in rats. The plasma protein binding, blood partitioning, and metabolic stability were determined by HPLC method. The oral pharmacokinetic study was analyzed by liquid chromatography coupled mass spectrometry (LC-MS/MS) method. The plasma protein binding of S009-0629 using modified charcoal adsorption method at 5 and 10 µg/mL was 80.58 ± 1.04% and 81.95 ± 1.15%, respectively. The K_RBC/PL of S009-0629 was independent of concentration and time. The in-vitro half-life of S009-0629 at 5 and 10 µM using rat liver microsomes was determined as 273 ± 24.46 and 281.67 ± 26.53 min, respectively. After oral administration, S009-0629 exhibited C_max 55.51 ± 1.18 ng/mL was observed at 18 hr (t_max ). S009-0629 was found to have the large apparent volume of distribution (1,894.93 ± 363.67 L/kg). Oral in-vivo t_1/2 of S009-0629 was found to be 41.23 ± 5.96 hr. A rapid and highly sensitive LC-MS/MS method was validated for S009-0629 in rat plasma. S009-0629 has high plasma protein binding and low hepatic extraction. S009-0629 has no affinity with human P-gp and BCRP in ATPase assay. After oral dosing, S009-0629 has slow absorption and elimination in rats.

Pharmacokinetics and disposition of miltefosine in healthy mice and hamsters experimentally infected with Leishmania infantum

Miltefosine is the only currently available oral drug for treatment of leishmaniasis. However, information on the pharmacokinetics (PK) of miltefosine is relatively scarce in animals. PK parameters and disposition of the molecule was determined in healthy NMRI mice and Syrian hamsters infected and treated with different miltefosine doses and regimens. Long half-life of the molecule was confirmed and differential pattern of accumulation of the drug was observed in analyzed organs in mice and hamster. Long treatment schedules produced miltefosine levels over IC₅₀ value against L. infantum intracellular amastigotes for at least 24 days in spleen and liver of infected hamsters. The observed differential pattern of organ accumulation of the drug in mice and hamster supports the relevance of both species for translational research on chemotherapy of leishmaniasis.

Chemometric-assisted method development in hydrophilic interaction liquid chromatography: A review

With an enormous growth in the application of hydrophilic interaction liquid chromatography (HILIC), there has also been significant progress in HILIC method development. HILIC is a chromatographic method that utilises hydro-organic mobile phases with a high organic content, and a hydrophilic stationary phase. It has been applied predominantly in the determination of small polar compounds. Theoretical studies in computer-aided modelling tools, most importantly the predictive, quantitative structure retention relationship (QSRR) modelling methods, have attracted the attention of researchers and these approaches greatly assist the method development process. This review focuses on the application of computer-aided modelling tools in understanding the retention mechanism, the classification of HILIC stationary phases, prediction of retention times in HILIC systems, optimisation of chromatographic conditions, and description of the interaction effects of the chromatographic factors in HILIC separations. Additionally, what has been achieved in the potential application of QSRR methodology in combination with experimental design philosophy in the optimisation of chromatographic separation conditions in the HILIC method development process is communicated. Developing robust predictive QSRR models will undoubtedly facilitate more application of this chromatographic mode in a broader variety of research areas, significantly minimising cost and time of the experimental work.

Hexadecylphosphocholine (Miltefosine) stabilized chitosan modified Ampholipospheres as prototype co-delivery vehicle for enhanced killing of L. donovani

Lipid nanoparticles are stable, biodegradable and biocompatible carriers offering excellent therapeutic efficacy. Here, a novel effort has been made to develop Miltefosine (HePC- hexadecylphosphocholine) stabilized chitosan anchored nanostructured lipid carriers (NLC) of Amphotericin B (AmB) as co-delivery vehicle to enhance killing of L. donovani. The entrapment efficiency of AmB was achieved upto 85.3% for HePC-AmB-CNLCs with mean particle size of 150.8±8.4nm, and zeta potential value of +28.2±1.1mV, respectively. The cumulative amount of AmB released at even after the 24h was less than 65% from HePC-AmB-CNLCs and Tween-80-AmB-CNLCs. Intravenous administration of HePC-AmB-CNLCs revealed the significantly increased localization of AmB in both liver and spleen when estimated. FACS study represented enhanced uptake of FITC-HePC-CNLCs over FITC-HePC-NLCs in J774A.1 cell lines. Highly significant in vitro and in vivo anti-leishmanial activity (p<0.05 compared with Tween 80-AmB-CNLCs) was observed with HePC-AmB-CNLCs when tested against VL in Leishmania donovani-infected hamsters. The haemolysis and cytotoxicity studies showed the safety of HePC-AmB-CNLCs and Tween 80-AmB-CNLCs. The findings suggested that it would be preferable to deliver AmB through HePC stabilized chitosan anchored nanostructured lipid carriers for rapid and effective treatment with decreased adverse effects.