Nanostructured lipid carriers based nanogel for meloxicam delivery: mechanistic, in-vivo and stability evaluation.

AIM: Our investigation was aimed to investigate the potential suitability of meloxicam-loaded nanostructured lipid carriers (MLX-NLC) gel for topical application. MAIN METHODS: MLX-NLC gel was prepared and in vivo skin penetration ability of the NLC gel was evaluated using confocal laser scanning microscopy. We studied the effect of MLX-NLC gel on the changes in lipid profile of skin to get an insight into its skin penetration enhancement mechanism. Acetic acid induced writhing test was performed to evaluate the analgesic effect. Drug concentration-time profile of MLX in rat plasma and skin after topical and oral treatment with MLX-NLC gel and oral MLX-solution, respectively, was observed. MLX-NLC gel was subjected to primary skin irritation test, sub-acute dermal toxicity study. Storage stability of MLX-NLC gel was also assessed for 90 days. KEY FINDINGS: NLC gel was effective in permeating Rhodamine 123 to deeper layers of rat skin. Changes in skin lipid prolife were observed in the rat skin on treatment with MLX-NLC gel and the results supported skin lipid extraction as a possible penetration enhancement mechanism. MLX-NLC gel demonstrated sustained pain inhibitory effect. Pharmacokinetics study established that topical application of MLX-NLC gel had the potential to avoid systemic uptake and hence the risk of systemic adverse effects. MLX-NLC gel demonstrated good skin tolerability and biosafety. Excellent physical stability of nanogel was observed at 4 ± 2 °C. SIGNIFICANCE: The study revealed that NLC gel is a promising carrier system for the topical application of MLX without side effects.

Microwave assisted synthesis of naphthopyrans catalysed by silica supported fluoroboric acid as a new class of non purine xanthine oxidase inhibitors.

A series of naphthopyrans was synthesized employing silica supported fluoroboric acid under solvent free conditions in a microwave reactor. The catalytic influence of HBF4-SiO2 was investigated in detail to optimize the reaction conditions. The synthesised compounds were evaluated for in vitro xanthine oxidase inhibitory activity for the first time. Structure-activity relationship analyses have also been presented. Among the synthesised compounds, NP-17, NP-19, NP-20, NP-23, NP-24, NP-25 and NP-26 were the active inhibitors with an IC50 ranging from 4 to 17 µM. Compound NP-19 with a thiophenyl ring at position 1 emerged as the most potent xanthine oxidase inhibitor (IC50=4 µM) in comparison to allopurinol (IC50=11.10 µM) and febuxostat (IC50=0.025 µM). The basis of significant inhibition of xanthine oxidase by NP-19 was rationalized by its molecular docking at MTE binding site of xanthine oxidase.

Synthesis and evaluation of naphthoflavones as a new class of non purine xanthine oxidase inhibitors.

In view of reported xanthine oxidase inhibitory potential of naphthopyrans and flavones, naphthoflavones as hybrids of the two were designed, synthesized and evaluated for in vitro xanthine oxidase inhibitory activity in the present study. The results of the assay revealed that the naphthoflavones possess promising inhibitory potential against the enzyme with IC50 values ranging from 0.62 to 41.2 µM. Structure activity relationship indicated that the nature and placement of substituents on the phenyl ring at 2nd position remarkably influences the inhibitory activity. Substitution of halo and nitro groups at ortho and para position of the phenyl ring (2nd position) remarkably favored the activity. NF-4 with p-fluoro phenyl ring was the most potent inhibitor with IC50 value of 0.62 µM. Enzyme kinetics study was also performed to investigate the inhibition mechanism and it was found that the naphthoflavones displayed mixed type inhibition. The basis of significant inhibition of xanthine oxidase by NF-4 was rationalized by molecular modeling studies.

Design, synthesis and evaluation of 2,4-diarylpyrano[3,2-c]chromen-5(4H)-one as a new class of non-purine xanthine oxidase inhibitors.

Abstract Keeping in view the recent success of molecular hybridization technique in drug design, 2,4-diarylpyrano[3,2-c]chromen-5(4H)-ones as conjugates of coumarins and chalcones have been designed and synthesized in the present study. The catalytic efficiency of various Lewis acids for the synthesis of designed conjugates under neat conditions was investigated, and SiO2 (200-400 mesh)-ZnCl2 was optimized as the best catalyst among the tested ones. The conjugates were evaluated for in-vitro xanthine oxidase activity. The results of the in-vitro assay were quite promising as some conjugates were endowed with remarkable inhibitory potential against the enzyme. HV-8, 11 and 12 were found to be high-potent inhibitors with HV-11 (the most potent inhibitor) possessing an IC50 value of 2.21 µM. The most active conjugate HV-11 was evaluated for the type of inhibition and was found to be a mixed type inhibitor. The compliance of some selected conjugates to the Lipinski rule was also calculated.

Synthesis and in vitro cytotoxic evaluation of N-alkylbromo and N-alkylphthalimido-isatins.

The manuscript pertains to the synthesis and in vitro cytotoxic evaluation of a series of N-alkylbromo and N-alkylphthalimido-isatins against four different human cancer cell lines namely Colon: HCT-15; Liver: Hep-2; Lung: A-549 and Leukemia: THP-1 at 10 and 100 µM concentrations. The active compounds based on preliminary studies were evaluated for their IC(50) value against six cell lines viz. Colo-205, HCT-15 (Colon), THP-1 (Leukemia), A-549 (Lung), PC-3 (Prostate) and HeLa (Cervix). The active analogue IS-4 exhibited IC(50) values of 4.57, 10.90, 11.75, 12.40 and 54.20 µM against HeLa, PC-3, HCT-15, THP-1 and Colo-205, respectively.

Anxiolytic effects of Equisetum arvense Linn. extracts in mice.

The petroleum ether (PE), chloroform (CH), ethanol (ETH) and water extracts of E. arvense stems were evaluated for anti-anxiety activity in mice using elevated plus maze model. Ketamine induced hypnosis and actophotometer was used to evaluate sedative effect with various extracts in mice. The results were compared with standard drug diazepam. The ethanolic extract of E. arvense (50 and 100 mg/kg) significantly increased the time-spent and the percentage of the open arm entries in the elevated plus-maze model which was comparable to diazepam. Ethanolic extract (100 mg/kg) prolonged the ketamine-induced total sleeping time and decreased the locomotor activity in mice. The results suggest that the ethanolic extract of E. arvense seems to possess anxiolytic effect with lower sedative activity than that of diazepam. The results could be attributed to the flavonoid content of the ethanolic extract.

4-aryl/heteroaryl-4H-fused Pyrans as Anti-proliferative Agents: Design, Synthesis and Biological Evaluation.

AIMS: The current study is focused on the design and synthesis of 4-aryl/heteroaryl-4H-fused pyrans as anti-proliferative agents. All the synthesized molecules were screened against a panel of human carcinoma cell lines. DESCRIPTION: Significant inhibition was exhibited by the compounds against HCT-116 (Colon) and PC-3 (Prostate) cell lines while A-549 (Lung) cell lines, MiaPaCa-2 (Pancreatic) cell lines and HL-60 (Leukemia Cancer) cell lines were almost resistant to the exposure of the test compounds. Compound FP-(v)n displayed noteworthy cytotoxicity towards HCT-116 malignant cells with the IC50 value of 0.67 µM. It induces apoptosis as revealed by several biological endpoints like apoptotic body formation, through DAPI staining, phase contrast microscopy and mitochondrial membrane potential loss. Moreover FP-(v)n is a potent apoptotic inducer confirmed by cell cycle arrest and ROS generation. The cell phase distribution studies indicate an augment from 4.94 % (control sample) to 39.68 % (sample treated with 1.5 µM compound FP-(v)n) in the apoptotic population. Compound FP-(v)n inhibits the tumor growth in Ehrlich ascites carcinoma (EAC), Ehrlich Tumor (ET, solid) and sarcoma-180 (solid) mice models. Additionally, it was established to be non-toxic at maximum tolerated dose of 1000 mg/kg in acute oral toxicity in Swiss-albino mice. CONCLUSION: The current study provides an insight into anti-cancer potential of FP-(v)n, which might be valuable in the treatment of tumor.

Design strategies, structure activity relationship and mechanistic insights for purines as kinase inhibitors.

Kinases control a diverse set of cellular processes comprising of reversible phosphorylation of proteins. Protein kinases play a pivotal role in human tumor cell proliferation, migration and survival of neoplasia. In the recent past, purine based molecules have emerged as significantly potent kinase inhibitors. In view of their promising potential for the inhibition of kinases, this review article focuses on purines which have progressed as kinase inhibitors during the last five years. A detailed account of the design strategies employed for the synthesis of purine analogs exerting inhibitory effects on diverse kinases has been presented. Apart from presenting the design strategies, the article also highlights the structure activity relationship along with mechanistic insights revealed during the biological evaluation of the purine analogs for kinase inhibition. The interactions with the amino acid residues responsible for kinase inhibitory potential of purine based molecules have also been discussed. In this assemblage, purine based protein kinase inhibitors patented in the past have also been summarized in the tabular form. This compilation will be of great interest for the researchers working in the area of protein kinase inhibitors.

4,6-diaryl Pyrimidones as Constrained Chalcone Analogues: Design, Synthesis and Evaluation as Antiproliferative Agents.

4,6-diarylpyrimidones as constrained chalcone analogues have been synthesised in the present study. The synthesised compounds were evaluated against a panel of human cancer cell lines. Striking selectivity was displayed by the compounds against MiaPaCa (Pancreatic) cell lines while PC-3 (prostate) and A-549 (lung) cell lines were almost resistant to the exposure of the test compounds. Compound SK - 25 exhibited remarkable cytotoxicity against MiaPaca-2 cell line with an IC50 value of 1.95 µM and was found to induce apoptosis evidenced through phase contrast microscopy, DAPI staining and mitochondrial membrane potential loss. The cell phase distribution studies indicated that the apoptotic population increased from 1.79% in control sample to 30.33 % in sample treated with 20 µM compound SK-25.

Rational approaches, design strategies, structure activity relationship and mechanistic insights for anticancer hybrids.

A Hybrid drug which comprises the incorporation of two drug pharmacophores in one single molecule are basically designed to interact with multiple targets or to amplify its effect through action on another bio target as one single molecule or to counterbalance the known side effects associated with the other hybrid part(.) The present review article offers a detailed account of the design strategies employed for the synthesis of anticancer agents via molecular hybridization techniques. Over the years, the researchers have employed this technique to discover some promising chemical architectures displaying significant anticancer profiles. Molecular hybridization as a tool has been particularly utilized for targeting tubulin protein as exemplified through the number of research papers. The microtubule inhibitors such as taxol, colchicine, chalcones, combretasatin, phenstatins and vinca alkaloids have been utilized as one of the functionality of the hybrids and promising results have been obtained in most of the cases with some of the tubulin based hybrids exhibiting anticancer activity at nanomolar level. Linkage with steroids as biological carrier vector for anticancer drugs and the inclusion of pyrrolo [2,1-c] [1,4]benzodiazepines (PBDs), a family of DNA interactive antitumor antibiotics derived from Streptomyces species in hybrid structure based drug design has also emerged as a potential strategy. Various heteroaryl based hybrids in particular isatin and coumarins have also been designed and reported to posses' remarkable inhibitory potential. Apart from presenting the design strategies, the article also highlights the structure activity relationship along with mechanistic insights revealed during the biological evaluation of the hybrids.

Chalcone based azacarboline analogues as novel antitubulin agents: design, synthesis, biological evaluation and molecular modelling studies.

The present study involves the design of a series of 3-aryl-9-acetyl-pyridazino[3,4-b]indoles as constrained chalcone analogues. A retrosynthetic route was proposed for the synthesis of target compounds. All the synthesized compounds were evaluated for in-vitro cytotoxicity against THP-1, COLO-205, HCT-116 and A-549 human cancer cell lines. The results indicated that 2a, 3a, 5a and 6a possessed significant cytotoxic potential with an IC50 value ranging from 1.13 to 5.76 µM. Structure activity relationship revealed that the nature of both Ring A and Ring B influences the activity. Substitution of methoxy groups on the phenyl ring (Ring A) and unsubstituted phenyl ring (Ring B) were found to be the preferred structural features. The most potent compound 2a was further tested for tubulin inhibition. Compound 2a was found to significantly inhibit the tubulin polymerization (IC50 value - 2.41 µM against THP-1). Compound 2a also caused disruption of microtubule assembly as evidenced by Immunoflourescence technique. The significant cytotoxicity and tubulin inhibition by 2a was rationalized by molecular modelling studies. The most potent structure was docked at colchicine binding site (PDB ID-1SA0) and was found to be stabilized in the cavity via various hydrophobic and hydrogen bonding interactions.

Preparation and evaluation of solid lipid nanoparticles based nanogel for dermal delivery of meloxicam.

The aim of the current investigation was to prepare and investigate the potential of solid lipid nanoparticles based gel (SLN-gel) for the dermal delivery of meloxicam (MLX). The meloxicam loaded SLN (MLX-SLN) gel was developed and characterized by means of photon correlation spectroscopy, rheometry, and differential scanning calorimetry to determine the physicochemical properties. The behavior of SLN gel on rat skin was evaluated in vitro using Franz diffusion cells to determine the skin permeation and penetration characteristics, in vivo on mice to determine the skin tolerance by histopathological examinations. The anti-inflammatory potential of SLN gel was assessed by carrageenan induced rat paw edema test. Biophysical studies including differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FTIR) were undertaken to study the interaction between the SLN gel and skin. MLX-SLN gel with nanometric particle size exhibited the controlled release abilities and simultaneously the potential to transport the drug to various skin layers. SLN gel displayed viscoelastic properties with predominantly elastic behavior and exhibited plastic flow. Biophysical studies elucidated the interaction between the SLN gel and stratum corneum (SC) lipids, and proposed the lipid bilayer fluidization as the possible mechanism for the increased penetration of meloxicam into skin. The nano-gel system showed marked anti-inflammatory activity and excellent skin tolerability. It can be concluded that SLN gel may be a promising delivery system for MLX in the treatment of inflammatory disorders.

Nanoemulsion based gel for transdermal delivery of meloxicam: physico-chemical, mechanistic investigation.

AIMS: The aim of the present investigation was to develop a nanoemulsion (NE) gel formulation for the transdermal delivery of meloxicam (MLX) in order to ensure maximum controlled and sustained drug release capacity. MAIN METHODS: The MLX containing NE gel was prepared and characterized for particle size, zeta potential, pH, rheology, in vitro drug release, in vitro skin permeation, and in vitro hemolysis. Differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR) of MLX-NE gel treated rat skin was performed to investigate the skin permeation mechanism of meloxicam from NE gel. Skin permeation potential of the developed gel formulation was assessed using confocal laser scanning microscopy (CLSM). The in vivo toxicity of MLX-NE gel was assessed by histopathological examination in rat. The rat paw edema test was performed to evaluate the anti-inflammatory activity of MLX-NE gel. KEY FINDINGS: Percutaneous absorption studies demonstrated a higher permeation of meloxicam from NE gel, than the drug solution. FTIR and DSC studies supported stratum corneum lipid extraction as a possible penetration enhancer mechanism for MLX-NE gel. CLSM studies confirmed the permeation of the NE gel formulation to the deeper layers of the skin (up to 130 µm). MLX-NE gel turned out to be non-irritant, biocompatible, and provided maximum inhibition of paw edema in rats over 24 h in contrast to MLX solution. SIGNIFICANCE: The nanoemulsion gel formulation may hold promise as an effective alternative for the transdermal delivery of meloxicam.

Development and characterization of a novel controlled release drug delivery system based on nanostructured lipid carriers gel for meloxicam.

AIM: The main objective of the current investigation was to develop nanostructured lipid carriers (NLC) based gel for the enhancement of transdermal absorption of meloxicam (MLX) to achieve local as well as systemic drug action without concurrent gastrointestinal toxicity. MAIN METHODS: NLC gel containing MLX was prepared and characterized for particle size, polydispersity, zeta potential, pH, rheology, entrapment efficiency, occlusion factor, and thermal behavior. In vitro drug release, in vitro skin permeation and deposition studies were carried out using Franz diffusion cells. Differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FTIR) of MLX-NLC gel treated stratum corneum (SC) were undertaken to get an insight into the skin permeation enhancement mechanism of MLX-NLC gel. Toxicity potential of the developed gel formulation was assessed by in vitro hemolysis and histopathological examinations. The rat paw edema test was performed to evaluate the anti-inflammatory activity of MLX-NLC gel. KEY FINDINGS: MLX-NLC gel demonstrated sustained release and enhanced the skin permeation and deposition of meloxicam especially into the dermis in comparison to meloxicam gel (control). MLX-NLC had an impact on the barrier properties of the skin and acted via protein and lipid modifications in the stratum corneum. MLX-NLC gel turned out to be hemocompatible, non-irritant, and non toxic with significant anti-inflammatory activity. SIGNIFICANCE: The results suggest that NLC gel could be a promising carrier for the transdermal delivery of meloxicam.

1,2,3-Triazole tethered ß-lactam-chalcone bifunctional hybrids: synthesis and anticancer evaluation.

The manuscript describes the synthesis of novel 1,2,3-triazole tethered ß-lactam-chalcone bifunctional hybrids via click chemistry approach utilizing azide-alkyne cycloaddition reactions and their evaluation as anticancer agents against four human cancer cell lines. The presence of a cyclohexyl substituent at N-1 of ß-lactam ring and methoxy substituents, preferably ortho on ring A and para on ring B on chalcones markedly improved the anticancer profiles of the synthesized scaffolds with the most potent of the test compound exhibiting an IC(50) value of <1, 67.1, <1 and 6.37 µM against A-549(lung), PC-3(prostate), THP-1(leukemia), and Caco-2(colon) cell lines, respectively.

Azide-alkyne cycloaddition en route to novel 1H-1,2,3-triazole tethered isatin conjugates with in vitro cytotoxic evaluation.

1H-1,2,3-triazole tethered isatin conjugates have been synthesized and evaluated for cytotoxicity on four human cancer cell lines. The results revealed 5a, 5c, 5e and 5n proved to be twice as potent as 5-fluorouracil on THP-1 cell line with 5a and 5c being most active exhibiting IC(50) values of <1 against all cell lines except Caco-2. Activity profiles showed dependence on the substituents on isatin rings with a preference for hydrogen while a strong electron withdrawing fluoro as well as nitro substituents on either ring decreased the anticancer activity.