Pharmacokinetics, pharmacodynamics and safety profiling of IS01957, a preclinical candidate possessing dual activity against inflammation and nociception

ADME/PK Insights of Crocetin: A Molecule Having an Unusual Chemical Structure with Druglike Features

Crocetin is a promising phyto-based molecule to treat Alzheimer's disease (AD). The chemical structure of crocetin is incongruent with various standard structural features of CNS drugs. As poor pharmacokinetic behavior is the major hurdle for any candidate to become a drug, we elucidated its druggable characteristics by implementing in silico, in vitro, and in vivo approaches, as limited ADME/PK information is available. Results demonstrate several attributes of crocetin based on rules of drug-likeness, lipophilicity, pKa, P-gp inhibitory activity, plasma stability, RBC partitioning, metabolic stability, CYP inhibitory action, blood-brain barrier (BBB) permeability, oral bioavailability, and pharmacokinetic interaction with marketed anti-Alzheimer's drugs (memantine, donepezil, galantamine, and rivastigmine). However, aqueous solubility, chemical stability, plasma protein binding, and P-gp induction are some concerns associated with this molecule that should be taken into consideration during its further development. Overall results indicate favorable ADME/PK behavior and potential druggable candidature of crocetin.

Orally bioavailable styryl derivative of rohitukine-N-oxide inhibits CDK9/T1 and the growth of pancreatic cancer cells

The chromone alkaloid is one of the classical pharmacophores for cyclin-dependent kinases (CDKs) and represents the first CDK inhibitor to reach clinical trials. Rohitukine (1), a chromone alkaloid isolated from Dysoxylum binectariferum inspired the discovery of several clinical candidates. The N-oxide derivative of rohitukine occurs naturally, with no reports on its biological activity. Herein, we report isolation, biological evaluation, and synthetic modification of rohitukine N-oxide for CDK9/T1 inhibition and antiproliferative activity in cancer cells. Rohitukine N-oxide (2) inhibits CDK9/T1 (IC₅₀ 7.6 μM) and shows antiproliferative activity in the colon and pancreatic cancer cells. The chloro-substituted styryl derivatives, 2b, and 2l, inhibit CDK9/T1 with IC₅₀ values of 0.17 and 0.15 μM, respectively. These derivatives display cellular antiproliferative activity in HCT 116 (colon) and MIA PaCa-2 (pancreatic) cancer cells with GI₅₀ values of 2.5-9.7 μM with excellent selectivity over HEK293 (embryonic kidney) cells. Both analogs induce cell death in MIA PaCa-2 cells via inducing intracellular ROS production, reducing mitochondrial membrane potential, and inducing apoptosis. These analogs are metabolically stable in liver microsomes and have a decent oral pharmacokinetics in BALB/c mice. The molecular modeling studies indicated their strong binding at the ATP-binding site of CDK7/H and CDK9/T1.

Design, Synthesis, and Pharmacological Evaluation of Embelin-Aryl/alkyl Amine Hybrids as Orally Bioavailable Blood-Brain Barrier Permeable Multitargeted Agents with Therapeutic Potential in Alzheimer's Disease: Discovery of SB-1448

The complex and multifaceted nature of Alzheimer's disease has brought about a pressing demand to develop ligands targeting multiple pathways to combat its outrageous prevalence. Embelin is a major secondary metabolite of Embelia ribes Burm f., one of the oldest herbs in Indian traditional medicine. It is a micromolar inhibitor of cholinesterases (ChEs) and β-site amyloid precursor protein cleaving enzyme 1 (BACE-1) with poor absorption, distribution, metabolism, and excretion (ADME) properties. Herein, we synthesize a series of embelin-aryl/alkyl amine hybrids to improve its physicochemical properties and therapeutic potency against targeted enzymes. The most active derivative, 9j (SB-1448), inhibits human acetylcholinesterase (hAChE), human butyrylcholinesterase (hBChE), and human BACE-1 (hBACE-1) with IC₅₀ values of 0.15, 1.6, and 0.6 μM, respectively. It inhibits both ChEs noncompetitively with k_i values of 0.21 and 1.3 μM, respectively. It is orally bioavailable, crosses blood-brain barrier (BBB), inhibits Aβ self-aggregation, possesses good ADME properties, and protects neuronal cells from scopolamine-induced cell death. The oral administration of 9j at 30 mg/kg attenuates the scopolamine-induced cognitive impairments in C57BL/6J mice.

In Silico Computational Studies of Bioactive Secondary Metabolites from Wedelia trilobata against Anti-Apoptotic B-Cell Lymphoma-2 (Bcl-2) Protein Associated with Cancer Cell Survival and Resistance

In the present study, the binding affinity of 52 bioactive secondary metabolites from Wedelia trilobata towards the anti-apoptotic B-cell lymphoma-2 (Bcl-2) protein (PDB: 2W3L) structure was identified by using in silico molecular docking and molecular dynamics simulation. The molecular docking results demonstrated that the binding energies of docked compounds with Bcl-2 protein ranged from -5.3 kcal/mol to -10.1 kcal/mol. However, the lowest binding energy (-10.1 kcal/mol) was offered by Friedelin against Bcl-2 protein when compared to other metabolites and the standard drug Obatoclax (-8.4 kcal/mol). The molecular dynamics simulations revealed that the Friedelin-Bcl-2 protein complex was found to be stable throughout the simulation period of 100 ns. Overall, the predicted Absorption, Distribution, Metabolism, Excretion, and Toxicity (ADMET) properties of Friedelin are relatively better than Obatoclax, with the most noticeable differences in many parameters where Friedelin has no AMES toxicity, hepatotoxicity, and skin sensitization. The ADMET profiling of selected compounds supported their in silico drug-likeness properties. Based on the computational analyses, the present study concluded that Friedelin of W. trilobata was found to be the potential inhibitor of the Bcl-2 protein, which merits attention for further in vitro and in vivo studies before clinical trials.

Assessment of the CYP1A2 Inhibition-Mediated Drug Interaction Potential for Pinocembrin Using In Silico, In Vitro, and In Vivo Approaches

Pinocembrin, a bioflavonoid, is extensively used in complementary/alternative medicine. It turns out as a promising candidate against neurodegenerative diseases because of its multifaceted pharmacological action toward neuroprotection. However, literature evidence is still lacking for its inhibitory action on CYP1A2, which is responsible for xenobiotic metabolism leading to the generation of toxic metabolites and bioactivation of procarcinogens. In the present study, our aim was to evaluate the CYP1A2 inhibitory potential of pinocembrin via in silico, in vitro, and in vivo investigations. From the results of in vitro studies, pinocembrin is found to be a potent and competitive inhibitor of CYP1A2. In vitro-in vivo extrapolation results indicate the potential of pinocembrin to interact with CYP1A2 substrate drugs clinically. Molecular docking-based in silico studies demonstrate the strong interaction of pinocembrin with human CYP1A2. In in vivo investigations using a rat model, pinocembrin displayed a marked alteration in the plasma exposure of CYP1A2 substrate drugs, namely, caffeine and tacrine. In conclusion, pinocembrin has a potent CYP1A2 inhibitory action to cause drug interactions, and further confirmatory study is warranted at the clinical level.

Pharmacokinetic Assessment of Rottlerin from Mallotus philippensis Using a Highly Sensitive Liquid Chromatography-Tandem Mass Spectrometry-Based Bioanalytical Method

Rottlerin is a key bioactive phytoconstituent present in the pericarp of Mallotus philippensis. It shows promising multifaceted pharmacological actions against cancer. However, there is hardly any report for the quantification of rottlerin in the biological matrix and on its pharmacokinetic behavior. Therefore, we aimed in the present study to assess selective in vitro ADME properties and in vivo pharmacokinetics of isolated and characterized rottlerin using a newly developed and validated liquid chromatography-tandem mass spectrometry-based highly sensitive bioanalytical method. The method was found to be simple (mobile phase and analytical column), sensitive (1.9 ng/mL), and rapid (run time of 2.5 min). All the validation parameters were within the acceptable criteria of the United States Food and Drug Administration's bioanalytical method validation guideline. The method was found to be very useful to assess lipophilicity, plasma stability, metabolic stability, plasma protein binding of rottlerin, as well as its oral and intravenous pharmacokinetics in mice. Rottlerin showed a number of drug-like pharmacokinetic properties (in vitro). Moreover, it displayed an excellent half-life (>2 h) and oral bioavailability (>35%) as compared to other members of natural phenolics. The present study is the first-time report of in vitro ADME properties and in vivo preclinical pharmacokinetics of rottlerin. The generated information is very much useful for its further development as a phytotherapeutics toward cancer therapy.

Antiarthritic activity of OA-DHZ; a gastroprotective NF-κB/MAPK/COX inhibitor

Arthritis, a primary autoimmune disorder having a global incidence of 2.03% person/year, is presently being treated by many commercially available drugs that treat symptomatically or improve the disease's clinical state; however, all the therapies pose varying amount of side effects. Therefore, it has become a fundamental need to search for therapeutics that offer better efficacy and safety profile, and the natural or nature-derived products are known for their outstanding performance in this arena. OA-DHZ, known to possess anti-inflammatory and analgesic properties, when explored for its efficacy against arthritis in adjuvant-induced arthritis (AIA) model, was found to inhibit paw edema by 34% and TNF-α, IL-6, and IL-1β by 67%, 39%, and 45% respectively when compared to diseased control. It was also able to reduce the inflamed spleen size by 45% and successfully normalized biochemical and hematological changes that followed arthritis. In vitro studies revealed that the underlying mechanism for inhibiting arthritis progression might be due to NF-κB /MAPK pathway modulation. OA-DHZ also showed selective inhibition of COX-2 in vitro while showing gastroprotective effects when evaluated for ulcerogenic and antiulcer potential in vivo. In contrast to the results obtained from in vivo experimentation, there is a disparity in the pharmacokinetic profile of OA-DHZ, where it showed low oral exposure and high clearance rate. OA-DHZ being antiarthritic acting via NF-κB /MAPK/ COX inhibition while showing gastroprotective effects, can be a suitable candidate to be in the drug pipeline and further exploration.

Effect of rutin on pharmacokinetic modulation of diclofenac in rats

Diclofenac is an extensively used nonsteroidal anti-inflammatory drug, but gastrointestinal liabilities and cardiovascular complications take the shine away from such a widely prescribed drug. On the other hand, rutin, a dietary bioflavonoid, has quite a few pharmacological attributes to improve the efficacy and reduce the dose-related toxicities of diclofenac through the intended food-drug/herb-drug interaction. The aim of the present research work was to investigate the role of rutin on pharmacokinetic modulation and the consequent efficacy of diclofenac. At first, pharmacodynamics and pharmacokinetics of diclofenac as alone and in the presence of rutin were investigated orally in a rat model. Then, mechanistic studies were performed to explain the effect of rutin on improvement in oral exposure as well as the efficacy of diclofenac using a battery of in-vitro/in-situ/in-vivo studies. Results displayed that rutin enhanced efficacy as well as oral bioavailability of diclofenac in rats. A marked increase in permeability of diclofenac by rutin was displayed that is linked to inhibition of Breast Cancer Resistance Protein (BCRP) transporters. There was no significant effect of rutin on the modulation of intestinal transit, CYP2C9 inhibition in human liver microsomes, and CYP2C9/CYP2C11 expression in rat liver tissues to boost the oral exposure of diclofenac. Rutin is found to be an inhibitor for BCRP transporters and can act as an oral bioavailability enhancer for a drug like diclofenac.

Anti-inflammatory and analgesic potential of OA-DHZ; a novel semisynthetic derivative of dehydrozingerone

Despite various advances in the arena of the current system of medicine, there are numerous side effects associated with the therapeutics which essentially demand research on the development of safer therapeutics. One way is to explore the bioactive plant secondary metabolites and their semisynthetic derivatives. In context to this, we analyzed OA-DHZ, a dehydrozingerone derivative as the later has been reported to show anti-inflammatory and analgesic properties. OA-DHZ was found to be having promising anti-inflammatory and analgesic potential. OA-DHZ was found to inhibit the carrageenan-induced edema and leukocyte migration, acetic acid-induced increase in vascular permeability and lipopolysaccharide-induced pro-inflammatory cytokines like TNF-α, IL-6, and IL-1β. Meanwhile, it was also found to potentially inhibit thermally as well as chemically induced pain signifying its analgesic/nociceptive potential. Further, safety pharmacology studies using in vivo animal models for the central nervous system, gastrointestinal tract, the cardio-respiratory system suggest that optimum functioning of vital organ systems does not get altered after single oral administration. Also, the acute toxicity study revealed its nontoxic nature up to 2000 mg/kg. This study paves the way for future exploration and development of OA-DHZ based on its potent activity and nontoxic nature.

Description of Druglike Properties of Safranal and Its Chemistry behind Low Oral Exposure

Safranal, a plant secondary metabolite isolated from saffron, has been reported for several promising pharmacological properties toward the management of Alzheimer's disease. In the present study, we observe and report for the first time about several druglike attributes of safranal, such as adherence to Lipinski's rule of five; optimum lipophilicity; high permeability; low blood-to-plasma ratio; less to moderate propensity to interact with P-glycoprotein (P-gp) or breast cancer-resistant protein (BCRP) transporters; and high plasma protein binding as common to most of the marketed drugs using in vitro and ex vivo models. In spite of the above attributes, in vivo oral absorption was found to be very poor, which is linked to the structural integrity of safranal in simulated gastric fluid, simulated intestinal fluid, plasma, and liver microsomes. Moreover, the presence of unsaturated aldehyde moiety in safranal remains in equilibrium with its hydroxylated acetal form. Further research work is required to find out the stable oral absorbable form of safranal by derivatization of its aldehyde group without losing its potency.

Effect of Natural Phenolics on Pharmacokinetic Modulation of Bedaquiline in Rat to Assess the Likelihood of Potential Food-Drug Interaction

Bedaquiline (TMC-207) is a recently approved drug for the treatment of multidrug-resistant tuberculosis (MDR-TB). Moreover, there is a present and growing concern for natural-product-mediated drug interaction, as these are inadvertently taken by patients as a dietary supplement, food additive, and medicine. In the present study, we investigated the impact of 20 plant-based natural products, typically phenolics, on in vivo oral bedaquiline pharmacokinetics, as previous studies are lacking. Three natural phenolics were identified that can significantly enhance the oral exposure of bedaquiline upon coadministration. We further investigated the possible role of all of the phytochemicals on in vitro P-glycoprotein (P-gp) induction and inhibition and CYP3A4 inhibition in a single platform as bedaquiline is the substrate for both P-gp and CYP3A4. In conclusion, curcumin, CC-I (3',5-dihydroxyflavone-7-O-β-d-galacturonide-4'-O-β-d-glucopyranoside), and 6-gingerol should not be coadministered with bedaquiline to avoid untoward drug interactions and, subsequently, its dose-dependent adverse effects.

Green chemistry appended synthesis, metabolic stability and pharmacokinetic assessment of medicinally important chromene dihydropyrimidinones

A green chemistry approach has been developed for the synthesis of chromene dihydropyrimidinone (CDHPM) using recyclable Fe/Al pillared clay catalyst. Pharmacokinetic parameters like aqueous solubility, lipophilicity, P-glycoprotein (P-gp) ATPase activity, permeability, plasma protein binding, red blood cell (RBC) partitioning, metabolic stability in liver microsomes and in silico computations have been studied for the most potent anticancer chromene dihydropyrimidinone hybrid 1. This compound exhibited low solubility, optimum lipophilicity, no P-gp inhibitory activity, intermediate permeability, high plasma protein binding, low RBC partitioning, acceptable metabolic stability in rat liver microsomes (RLM) as well as human liver microsomes (HLM) with transitional hepatic extraction ratio.

Effect of IS01957, a para-coumaric acid derivative on pharmacokinetic modulation of diclofenac through oral route for augmented efficacy

Diclofenac is one of the world's largest selling nonsteroidal anti-inflammatory drugs. The major concerns related to oral diclofenac therapy are gastrointestinal and cardiovascular side effects for which explicitly emphasis has been given to use it at lowest effective dose for the shortest duration. On the other hand, IS01957 has been designed under the purview of anti-inflammatory drug and bioavailability enhancer. IS01957 have dual action on inflammation and nociception with acceptable safety profile. In the quest for a suitable combination with improved therapeutic efficacy and better tolerability, pharmacodynamic and pharmacokinetic interaction studies were performed for diclofenac with or without IS01957 in mice model. Results showed that IS01957 enhanced both anti-inflammatory effect and plasma concentration of diclofenac upon concomitant oral administration. These interesting results steered to enumerate the possible role of IS01957 towards diclofenac pharmacokinetics through a panel of mechanistic investigations: (a) BCRP dependent ATPase activity was markedly interfered by IS01957; (b) IS01957 increased the intestinal permeability of diclofenac in the single pass in-situ perfusion model; (c) IS01957 inhibited the CYP2C9 catalyzed diclofenac 4-hydroxylation in human liver microsomes. Immunoblotting results suggest that diclofenac action was improved significantly in the presence of IS01957 involving MAPK pathways. Finally acute gastric damage study showed that IS01957 in combination with diclofenac was better to improve the desired PGE₂ level as compare to alone. In nutshell, IS01957 have potential to augment the efficacy of diclofenac through pharmacokinetic modulation. Further investigations are required for dose reduction of diclofenac to combat its liabilities before going into clinical setting.

Design, synthesis and biological evaluation of pyrazolopyrimidinone based potent and selective PDE5 inhibitors for treatment of erectile dysfunction

Our previous discovery of series of pyrazolopyrimidinone based PDE5 inhibitors led to find potent leads but with low aqueous solubility and poor bioavailability, and low selectivity. Now, a new series of same pyrazolopyrimidinone scaffold is designed, synthesized and evaluated for its PDE5 inhibitory potential. In this study, some of the molecules are found more potent and selective PDE5 inhibitors in vitro than sildenafil. The studies revealed that compound 5 is 20 fold selective to PDE5 against PDE6. As PDE6 enzyme is involved in the phototransduction pathway in the retina and creates distortion problem, the selectivity for PDE5 specifically against PDE6 enzyme is preferred for any development candidate and in present study, compound 5 has been found to be devoid of this liability of selectivity issue. Moreover, compound 5 has shown excellent in vivo efficacy in conscious rabbit model, it's almost comparable to sildenafil. The preclinical pharmacology including pharmacokinetic and physicochemical parameter studies were also performed for compound 5, it was found to have good PK properties and other physicochemical parameters. The development of these selective PDE5 inhibitors can further lead to draw strategies for the novel preclinical and/or clinical candidates based on pyrazolopyrimidinone scaffold.

Pharmacokinetic evaluation of medicinally important synthetic N,N' diindolylmethane glucoside: Improved synthesis and metabolic stability

An improved route for the synthesis of N,N'-diindolyl methane (DIM) glycosides has been developed by using Fe/Al pillared clay catalyst. In-silico pharmacokinetics followed by in-vitro studies like aqueous solubility, lipophilicity, P-glycoprotein (P-gp) dependent ATPase activity, permeability, plasma protein binding, RBC partitioning, metabolic stability in different liver microsomes and its in-vitro-in-vivo extrapolation were conducted for the most potent derivative namely NGD16. The compound was found to have low solubility, optimum lipophilicity, no P-gp inhibitory activity, intermediate permeability, high plasma protein binding, low RBC partitioning, acceptable metabolic stability in rat liver microsomes (RLM) as well as human liver microsomes (HLM) with intermediate hepatic extraction ratio.

Intervention of curcumin on oral pharmacokinetics of daclatasvir in rat: A possible risk for long-term use

Curcumin, a natural diarylheptanoid, is extensively used as a food additive or dietary supplement on the regular basis. It is known to have potential to encumber the drug transporters and hepatic drug metabolizing enzymes that lead to pharmacokinetic interactions with drug or food. Daclatasvir is a new orally acting drug for the treatment of chronic Hepatitis C Virus infections. This is a substrate of P-glycoprotein and CYP3A4 that are involved in the major pharmacokinetic interaction. Hence, the studies' aim is to assess for any possible pharmacokinetic interactions. Pharmacokinetic studies of daclatasvir in presence or absence of curcumin were carried out in Wistar rats following oral administration. Parallelly, the oral pharmacokinetics of daclatasvir was also determined in the presence of ketoconazole or quinidine. Studies revealed that plasma level of daclatasvir was not altered significantly during concomitant single dose administration of curcumin, whereas significantly decreased upon pretreatment for 7 days with curcumin at high dose level. Ketoconazole and quinidine markedly increase daclatasvir exposure following concomitant administration with daclatasvir. It can be concluded that dose adjustment is unlikely to be required for intermittent use of curcumin at low dose but cautious for chronic and concomitant use of curcumin at a high dose.