Synthesis of α,α-Difluoro-β-amino Ketones from N-Boc-α-Amidosulfones and Pentafluoro-gem-diols

To circumvent the synthesis and isolation of imines, a method was devised to construct α,α-difluoro-β-amino ketones from N-Boc-α-amidosulfones. The reactive nucleophiles, difluoroenolates, are generated in situ from the pentafluoro-gem-diols using cesium fluoride in pyridine. NMR studies confirm the role of the α-amidosulfones in this process. Incubation of the α,α-difluoro-β-amino ketones in rat serum demonstrates the relative stability of this structure as well as its value as a chemical probe or lead.

Formulation and In Vitro-Ex vivo Evaluation of Cannabidiol and Cannabidiol-Valine-Hemisuccinate Loaded Lipid-Based Nanoformulations for Ocular Applications

The goal of this investigation is to develop stable ophthalmic nanoformulations containing cannabidiol (CBD) and its analog cannabidiol-valine-hemisuccinate (CBD-VHS) for improved ocular delivery. Two nanoformulations, nanoemulsion (NE) and nanomicelles (NMC), were developed and evaluated for physicochemical characteristics, drug-excipient compatibility, sterilization, thermal analysis, surface morphology, ex-vivo transcorneal permeation, corneal deposition, and stability. The saturation solubility studies revealed that among the surfactants tested, Cremophor EL had the highest solubilizing capacity for CBD (23.3 ± 0.1 mg/mL) and CBD-VHS (11.2 ± 0.2 mg/mL). The globule size for the lead CBD formulations (NE and NMC) ranged between 205 and 270 nm while CBD-VHS-NMC formulation had a particle size of about 78 nm. The sterilized formulations, except for CBD-VHS-NMC at 40 °C, were stable for three months of storage (last time point tested). Release, in terms of CBD, in the in-vitro release/diffusion studies over 18 h, were faster from the CBD-VHS nanomicelles (38 %) compared to that from the CBD nanoemulsion (16 %) and nanomicelles (33 %). Transcorneal permeation studies revealed improvement in CBD permeability and flux with both formulations; however, a greater improvement was observed with the NMC formulation compared to the NE formulation. In conclusion, the nanoformulations prepared could serve as efficient topical ocular drug delivery platforms for CBD and its analog.

Synthesis and biological evaluation of tert-butyl ester and ethyl ester prodrugs of L-γ-methyleneglutamic acid amides for cancer

In cancer cells, glutaminolysis is the primary source of biosynthetic precursors. Recent efforts to develop amino acid analogues to inhibit glutamine metabolism in cancer have been extensive. Our lab recently discovered many L-γ-methyleneglutamic acid amides that were shown to be as efficacious as tamoxifen or olaparib in inhibiting the cell growth of MCF-7, SK-BR-3, and MDA-MB-231 breast cancer cells after 24 or 72 h of treatment. None of these compounds inhibited the cell growth of nonmalignant MCF-10A breast cells. These L-γ-methyleneglutamic acid amides hold promise as novel therapeutics for the treatment of multiple subtypes of breast cancer. Herein, we report our synthesis and evaluation of two series of tert-butyl ester and ethyl ester prodrugs of these L-γ-methyleneglutamic acid amides and the cyclic metabolite and its tert-butyl esters and ethyl esters on the three breast cancer cell lines MCF-7, SK-BR-3, and MDA-MB-231 and the nonmalignant MCF-10A breast cell line. These esters were found to suppress the growth of the breast cancer cells, but they were less potent compared to the L-γ-methyleneglutamic acid amides. Pharmacokinetic (PK) studies were carried out on the lead L-γ-methyleneglutamic acid amide to establish tissue-specific distribution and other PK parameters. Notably, this lead compound showed moderate exposure to the brain with a half-life of 0.74 h and good tissue distribution, such as in the kidney and liver. Therefore, the L-γ-methyleneglutamic acid amides were then tested on glioblastoma cell lines BNC3 and BNC6 and head and neck cancer cell lines HN30 and HN31. They were found to effectively suppress the growth of these cancer cell lines after 24 or 72 h of treatment in a concentration-dependent manner. These results suggest broad applications of the L-γ-methyleneglutamic acid amides in anticancer therapy.

Interval delivery of 5HT2A agonists using multilayered polymer films

There is an urgent unmet medical need to develop therapeutic options for the ~50% of depression patients suffering from treatment-resistant depression, which is difficult to treat with existing psycho- and pharmaco-therapeutic options. Classical psychedelics, such as the 5HT_2A agonists, have re-emerged as a treatment paradigm for depression. Recent clinical trials highlight the potential effectiveness of 5HT_2A agonists to improve mood and psychotherapeutic growth in treatment-resistant depression patients, even in those who have failed a median of four previous medications in their lifetime. Moreover, microdosing could be a promising way to achieve long-term alleviation of depression symptoms without a hallucinogenic experience. However, there are a gamut of practical barriers that stymie further investigation of microdosing 5HT_2A agonists, including: low compliance with the complicated dosing regimen, high risk of diversion of controlled substances, and difficulty and cost administering the long-term treatment regimens in controlled settings. Here, we developed a drug delivery system composed of multilayered cellulose acetate phthalate (CAP)/Pluronic F-127 (P) films for the encapsulation and interval delivery of 5HT_2A agonists from a fully biodegradable and biocompatible implant. CAPP film composition, thickness, and layering strategies were optimized, and we demonstrated three distinct pulses from the multilayered CAPP films in vitro. Additionally, the pharmacokinetics and biodistribution of the 5HT_2A agonist 2,5-Dimethoxy-4-iodoamphetamine (DOI) were quantified following the subcutaneous implantation of DOI-loaded single and multilayered CAPP films. Our results demonstrate, for the first time, the interval delivery of psychedelics from an implantable drug delivery system and open the door to future studies into the therapeutic potential of psychedelic delivery.

Development of α-Tocopherol Succinate-Based Nanostructured Lipid Carriers for Delivery of Paclitaxel

The management of retinoblastoma (RB) involves the use of invasive treatment regimens. Paclitaxel (PTX), an effective antineoplastic compound used in the treatment of a wide range of malignant tumors, poses treatment challenges due to systemic toxicity, rapid elimination, and development of resistance. The goal of this work was to develop PTX-loaded, α-tocopherol succinate (αTS)-based, nanostructured lipid carrier (NLCs; αTS-PTX-NLC) and PEGylated αTS-PTX-NLC (αTS-PTX-PEG-NLC) to improve ocular bioavailability. The hot homogenization method was used to prepare the NLCs, and repeated measures ANOVA analysis was used for formulation optimization. αTS-PTX-NLC and αTS-PTX-PEG-NLC had a mean particle size, polydispersity index and zeta potential of 186.2 ± 3.9 nm, 0.17 ± 0.03, −33.2 ± 1.3 mV and 96.2 ± 3.9 nm, 0.27 ± 0.03, −39.15 ± 3.2 mV, respectively. The assay and entrapment efficiency of both formulations was >95.0%. The NLC exhibited a spherical shape, as seen from TEM images. Sterilized (autoclaved) formulations were stable for up to 60 days (last time point checked) under refrigerated conditions. PTX-NLC formulations exhibited an initial burst release and 40% drug release, overall, in 48 h. The formulations exhibited desirable physicochemical properties and could lead to an effective therapeutic option in the management of RB.

Pharmacokinetics of Darolutamide in Mouse - Assessment of the Disposition of the Diastereomers, Key Active Metabolite and Interconversion Phenomenon: Implications to Cancer Patients

BACKGROUND

Darolutamide is recently approved for the treatment of non-metastatic castrate resistance prostate cancer. Hitherto, no stereoselective pharmacokinetic data have been published pertaining to darolutamide and its diastereomers in animals or humans. The key aims of the experiment were to examine darolutamide, S,S-darolutamide and S,R-darolutamide with respect to (a) assessment of in vitro metabolic stability and protein binding and (b) characterization of in vivo oral and intravenous pharmacokinetics in mice.

METHODS

In vitro (liver microsomes stability and protein binding) and in vivo experiments (oral/intravenous dosing to mice) were carried out using darolutamide, S,S-darolutamide and S,Rdarolutamide. Besides, tissue levels of darolutamide, S,S-darolutamide and S,R-darolutamide were measured following oral and intravenous dosing. Appropriate plasma/tissue samples served to determine the pharmacokinetics of various analytes in mice. Liquid chromatography in tandem with mass spectrometry procedures enabled the delineation of the plasma pharmacokinetics, in vitro and tissue uptake data of the various analytes.

RESULTS

Chiral inversion was absent in the metabolic stability study. However, darolutamide showed profound stereoselectivity (S,S-darolutamide greater than S,R-darolutamide) after either intravenous or oral dosing. S,R-darolutamide but not S,S-darolutamide showed conversion to its antipode post oral and intravenous dosing to mice. Regardless of oral or intravenous dosing, active keto darolutamide formation was evident after administration of darolutamide, S,S-darolutamide or S,R- darolutamide. Tissue data supported the observations in plasma; however, tissue exposure of darolutamide, S,Sdarolutamide and S,R-darolutamide was much lower as compared to plasma.

CONCLUSION

In lieu of the human pharmacokinetic data, although the administration of diastereomeric darolutamide was justified, it is proposed to delineate the clinical pharmacokinetics of S,Rdarolutamide and S,S-darolutamide relative to darolutamide in future clinical pharmacology studies.

A concise review of bioanalytical methods of small molecule immuno-oncology drugs in cancer therapy

Immuno-oncology (IO) is an emerging option to treat cancer malignancies. In the last two years, IO has accounted for more than 90% of the new active drugs in various therapeutic indications of oncology drug development. Bioanalytical methods used for the quantitation of various IO small molecule drugs have been summarized in this review. The most commonly used are HPLC and LC-MS/MS methods. Determination of IO drugs from biological matrices involves drug extraction from the biological matrix, which is mostly achieved by simple protein precipitation, liquid-liquid extraction and solid-phase extraction. Subsequently, quantitation is usually achieved by LC-MS/MS, but HPLC-UV has also been employed. The bioanalytical methods reported for each drug are briefly discussed and tabulated for easy access. Our review indicates that LC-MS/MS is a versatile and reliable tool for the sensitive, rapid and robust quantitation of IO drugs.

Uptake and pharmacokinetics of cefuroxime in rabbits after intravitreal, intracameral, and topical dosing: relevance to human ocular injection of cefuroxime

Cefuroxime is one of the widely used antibiotics. The objective of this study was to determine pharmacokinetics and disposition in various ocular tissues following topical (TOP), intracameral (IC) and intravitreal (IVT) administration of cefuroxime to rabbits.Following TOP, IC and IVT dosing plasma and various ocular tissues (aqueous humor (AH), vitreous humor (VH), conjunctiva, trabecular mesh (TM), lens and retina-choroid (RC)) were collected and analyzed to understand the disposition of cefuroxime. Postintravenous administration plasma samples were collected to determine the systemic pharmacokinetics.Post-TOP dosing cefuroxime concentrations were observed only in conjunctiva up to 48 h. IC administration showed cefuroxime concentrations in AH up to 8 h; in conjunctiva, TM and plasma, the concentration lasted up to 4 h and in RC and VH till 1 h. IVT administration of cefuroxime showed concentrations in all ocular tissues (up to 8 h) and lasted up to 48 h except in conjunctiva and RC.There was evidence that the mechanism(s) of cefuroxime entry into the eye by via IVT, IC and TOP routes is clearly different. The present ocular tissue data may aid clinicians for considering appropriate choice in the treatment of post-operative ocular complications due to bacterial infections including endophthalmitis.

Prediction of Human Pharmacokinetics of Fomepizole from Preclinical Species Pharmacokinetics Based on Normalizing Time Course Profiles

Fomepizole is used as an antidote to treat methanol poisoning due to its selectivity towards alcohol dehydrogenase. In the present study, the goal is to develop a method to predict the fomepizole human plasma concentration versus time profile based on the preclinical pharmacokinetics using the assumption of superimposability on simulated time course profiles of animals and humans. Standard allometric equations with/without correction factors were also assimilated in the prediction. The volume of distribution at steady state (Vss) predicted by simple allometry (57.55 L) was very close to the reported value (42.17 L). However, clearance (CL) prediction by simple allometry was at least 3-fold higher to the reported value (33.86 mL/min); hence, multiple correction factors were used to predict the clearance. Both brain weight and maximum life span potential could predict the CL with 1.22- and 1.01-fold difference. Specifically, the predicted Vss and CL values via interspecies scaling were used in the prediction of series of human intravenous pharmacokinetic parameters, while the simulation of human oral profile was done by the use of absorption rate constant (Ka) from dog following the applicability of human bioavailability value scaled from dog data. In summary, the findings indicate that the utility of diverse allometry approaches to derive the human pharmacokinetics of fomepizole after intravenous/oral dosing.

RP-HPLC-UV Method for Simultaneous Quantification of Second Generation Non-Steroidal Antiandrogens Along with their Active Metabolites in Mice Plasma: Application to a Pharmacokinetic Study

A simple, specific and reproducible high-performance liquid chromatography (HPLC) assay method has been developed and validated for the quantitation of second generation antiandrogens and their active metabolites namely apalutamide, enzalutamide, N-desmethylenzalutamide (active metabolite of enzalutamide), darolutamide and ORM-15341 (active metabolite of darolutamide) in mice plasma. The method involves extraction of apalutamide, enzalutamide, N-desmethylenzalutamide, darolutamide and ORM-15341 along with internal standard (IS) from 100 µL mice plasma through a simple protein precipitation process. The chromatographic analysis was performed on a Waters Alliance HPLC system using a gradient mobile phase (comprising 10 mM ammonium acetate and acetonitrile in a flow-gradient) and X-Terra Phenyl column. The UV detection wave length was set at λ_max 250 nm. Apalutamide, enzalutamide, N-desmethylenzalutamide, darolutamide and ORM-15341 and the IS eluted at 13.6, 11.4, 9.68, 6.11, 6.93 and 4.69 min, respectively with a total run time of 15 min. Method validation was performed as per regulatory guidelines and the results met the acceptance criteria. The calibration curve was linear over a concentration range of 209 - 5215 ng/mL (r ²=0.998). The intra- and inter-day precisions were in the range of 0.56-13.5 and 1.04-13.9%, respectively. The validated HPLC method was successfully applied to a pharmacokinetic study in mice.

Development and validation of a novel method for simultaneous quantification of enzalutamide, darolutamide and their active metabolites in mice dried blood spots using LC-MS/MS: Application to pharmacokinetic study in mice

A simple, sensitive and rapid assay method has been developed and validated for the estimation of enzalutamide, N-desmethylenzalutamide (active metabolite of enzalutamide), darolutamide and ORM-15341 (active metabolite of darolutamide) on mice dried blood spots (DBS) using liquid chromatography coupled to tandem mass spectrometry with electro spray ionization in the positive-ion mode. The method utilizes liquid extraction of enzalutamide, N-desmethylenzalutamide, darolutamide and ORM-15341 from 3 mm punched disks from DBS cards (spiked or study samples). The extracted sample was chromatographed using an isocratic mobile phase (0.2 % formic acid : acetonitrile; 30:70, v/v) on an Atlantis dC18 column. The total run time was 2.5 min. The MS/MS ion transitions monitored were m/z 465 → m/z 209, m/z 451 →  m/z 195, m/z 399 → m/z 178, m/z 397 →  m/z 194 and m/z 481 → m/z 453 for enzalutamide, N-desmethyl­enzalutamide, darolutamide, ORM-15341 and the IS (apalutamide-d3), respectively. Method validation was performed as per regulatory guideline. The assay had a good linearity over the range of 0.93-2000 ng/mL. The intra- and inter-batch accuracy and precision (%RE & RSD) across quality controls met the acceptance criteria for all the analytes. Stability studies showed that all the analytes were stable on DBS cards for one month. This novel method has been applied to analyze the DBS samples of enzalutamide, N-desmethylenzalutamide, darolutamide and ORM-15341 obtained from a pharmacokinetic study in mice.

Determination of Tofacitinib in Mice Whole Blood on Dried Blood Spots Using LC–ESI–MS/MS: Application to Pharmacokinetic Study in Mice

A simple, sensitive and rapid assay method has been developed and validated as per regulatory guideline for the estimation of tofacitinib on mice dried blood spots (DBS) using liquid chromatography coupled to tandem mass spectrometry with electro spray ionization in the positive-ion mode. The method employs liquid extraction of tofacitinib from DBS disk of mice whole blood followed by chromatographic separation using 5 mM ammonium acetate (pH 6.5):acetonitrile (20:80, v/v) at a flow rate of 0.60 mL/min on an X-Terra Phenyl column with a total run time 2.5 min. The MS/MS ion transitions monitored were m/z 313→149 for tofacitinib and m/z 316→149 for the internal standard (13C3, 15N-tofacitinib). The assay was linear in the range of 0.99–1980 ng/mL. The intra- and inter-day precision was in the range of 1.17–10.3 and 3.37–10.9%, respectively. Stability studies showed that tofacitinib was stable on DBS cards for one month. This novel method has been applied to analyze the DBS samples of tofacitinib obtained from a pharmacokinetic study in mice.

Prediction of Human Pharmacokinetics of Bendamustine from Preclinical Species Pharmacokinetics Based on Normalizing Time Course Profiles

Bendamustine, an alkylating anticancer agent, is used to treat chronic lymphocytic leukemia by intravenous infusion alone or in combination. The work aimed to develop a method to predict time vs. concentration profile for humans based on preclinical pharmacokinetics using the assumption of superimposability of normalized time course profiles of animals and humans. Standard allometric equations with/without correction factors (CF) were also used in prediction. The Vss was predicted by simple allometry of 0.312W^0.871 (r²=0.987), where W is body weight; predicted Vss (19.71 L) was similar to the reported value (20.10 L). However, CL prediction involved both simple and CF allometry. Best proximity CL (543 vs. 598 mL/min) was obtained with maximum life span correction (MLP) [2.46W^1.215 (r²=0.988)]. Normalized curves were obtained by normalizing the time (with mean residence time) vs. concentration (with dose/Vss) in animal species. The concentration vs. time profile in humans after intravenous infusion was then simulated using normalized curve for each animal species and the values of CL and Vss were predicted for humans. In summary the findings indicate that normalized time course approach could predict the bendamustine human pharmacokinetics and such an approach could be prospectively applied for analog drugs of this class.

Validated Chiral LC-ESI-MS/MS Method for the Simultaneous Quantification of Darolutamide Diastereomers and Its Active Metabolite in Mice Plasma: Application to a Pharmacokinetic Study

A simple, selective and reliable LC-MS/MS method was developed and validated for the simultaneous quantitation of darolutamide diastereomers (diastereomer-1 and diastereomer-2) and its active metabolite i. e. ORM-15341 in mice plasma using warfarin as an internal standard (IS) as per the regulatory guidelines. Plasma samples were extracted by liquid-liquid extraction and the chromatographic separation was achieved on a Chiralpak IA column with an isocratic mobile phase 5 mM ammonium acetate:absolute alcohol (20:80, v/v) at a flow rate of 1.0 mL/min. Detection and quantitation was done by multiple reaction monitoring on a triple quadrupole mass spectrometer following the transitions: m/z 397→202, 395→202 and 307→250 for darolutamide diastereomers, ORM-15341 and the IS, respectively in the negative ionization mode. The calibration curves were linear (r>0.992) in the range of 100-2400 ng/mL for all the analytes. The intra- and inter-day precisions were in the range of 1.25-10.2 and 1.58-12.3; 2.85-5.68 and 1.85-9.58; 2.34-12.1 and 2.58-7.38 for diastereomer-1, diastereomer-2 and ORM-15341, respectively. Both diastereomers and ORM-15341 were found to be stable under different stability conditions. The validated method was applied to a pharmacokinetic study in mice.

Preclinical assessment of ulixertinib, a novel ERK1/2 inhibitor

Ulixertinib (BVD-523) is a novel and selective reversible inhibitor of ERK1/ERK2. In xenograft studies it inhibited tumor growth in BRAF-mutant melanoma and colorectal xenografts as well as KRAS-mutant colorectal and pancreatic models. Ulixertinib is currently in Phase I clinical development for the treatment of advance solid tumors. The objective of the study is to assess the metabolic stability (in various pre-clinical and human liver microsomes/hepatocytes), permeability, protein binding, CYP inhibition, CYP induction and CYP phenotyping of ulixertinib. We have also studied the oral and intravenous pharmacokinetics of ulixertinib in mice, rats and dogs. Ulixertinib was found to be moderately to highly stable in various liver microsomes/hepatocytes tested. It is a medium permeable (2.67 x 10-6 cm /sec) drug and a substrate for efflux (efflux ratio: 3.02) in Caco-2 model. Ulixertinib was highly bound to plasma proteins. CYPs involved in its limited metabolism and it is CYP inhibition IC50 ranged between 10-20 µM. Post oral administration ulixertinib exhibited early Tmax (0.50-0.75 h) in mice and rats indicating absorption was rapid, however in dogs Tmax attained at 2 h. The half-life (t½) of ulixertinib by intravenous and oral routes ranged between 1.0-2.5 h across the species. Clearance and volume of distribution by intravenous route for ulixertinib were found to be 6.24 mL/min/kg and 0.56 L/kg; 1.67 mL/min/kg and 0.36 L/kg and 15.5 mL/min/kg and 1.61 L/kg in mice, rats and dogs, respectively. Absolute oral bioavailability in mice and rats was > 92 %, however in dogs it was 34 %.