A Molecular Insight into Pyrazole Congeners as Antimicrobial, Anticancer, and Antimalarial Agents.

BACKGROUND: Pyrazole is a bioactive heterocyclic congener with numerous biological and pharmacological functionalities. Due to their multiple prospective applications, developing innovative and novel pyrazoles and analogs, revealing revolutionary methods for synthesizing this nucleus, investigating diverse potencies of that heterocycle, and exploring possible pyrazole applications are becoming increasingly relevant. OBJECTIVES: Pyrazole scaffolds have been proven successful as antimicrobial, anticancer, and antimalarial therapeutics against multiple targets like DNA gyrase, topoisomerase IV, Hsp90, and several kinase enzymes. For this variability in the biotic zone, their moiety has gained the attention of many scientists interested in researching chemical and pharmacological profiles. RESULTS: The review covers pyrazole scaffolds with a variety of biological functions and attempts to connect the structure-activity relationship. Multiple pyrazole analogs have been produced as lead compounds, and their activities have been evaluated. CONCLUSION: The combination of pyrazole with other pharmacophores in a molecule might lead to novel potent therapeutic medicines, which could aid in the development of potent lead compounds.

The Emerging Role of Janus Kinase Inhibitors in the Treatment of Cancer.

Cancer is a leading cause of death worldwide. The Janus kinase (JAK) signal transducer and activator of transcription (STAT) signalling pathway are activated abnormally, which promotes carcinogenesis. Several cytokines are important cancer drivers. These proteins bind to receptors and use the Janus kinase (JAK) and STAT pathways to communicate their responses. Cancer risks are linked to genetic differences in the JAK-STAT system. JAK inhibitors have been shown to reduce STAT initiation, tissue propagation, and cell existence in preclinical investigations involving solid tumour cell line models. JAK inhibitors, notably ruxolitinib, JAK1 or 2 blockers, make cell lines and mouse models more susceptible to radiotherapy, biological response modifier therapy, and oncolytic viral treatment. Numerous JAK antagonists have been or are now being evaluated in cancerous patients as monotherapy or by combining with other drugs in clinical studies. In preclinical investigations, certain JAK inhibitors showed promising anticancer effects; however, clinical trials explicitly evaluating their effectiveness against the JAK/STAT system in solid tumours have yet to be completed. JAK inhibition is a promising strategy to target the JAK/STAT system in solid tumours, and it deserves to be tested further in clinical studies. The function of directing Janus kinases (JAKs), an upstream accelerator of STATs, as a technique for lowering STAT activity in various malignant circumstances is summarized in this article, which will help scientists to generate more specific drug molecules in the future.

Pyrazole Scaffolds: Centrality in Anti-Inflammatory and Antiviral Drug Design.

BACKGROUND: Pyrazole is a component of a diversity of bioactive heterocyclic congeners with a broad-spectrum range of biological and pharmacological uses. Designing novel pyrazole and its analogues, revealing new routes for synthesizing this nucleus, exploring various potencies of that heterocycles, and looking for possible applications of pyrazoles are all becoming more important due to their numerous potential applications. OBJECTIVES: Pyrazole scaffolds have been proven to be successful as anti-viral and anti-inflammatory therapeutics against multiple targets like HSV-1, NNRTI, H1N1, CoX-1, and CoX-2. Due to this miscellany in the biotic area, this moiety has engrossed the consideration of many scientists to study chemistry and pharmacological profile. RESULTS: The review encompasses pyrazole having various scaffolds with multiple biological activities and attempts have also been made to correlate their structure-activity relationship. Multiple pyrazole correspondents have been synthesized as lead molecules and performed valuation for their actions. CONCLUSION: The incorporation of pyrazole with other pharmacophores in the molecule might lead to novel potent therapeutic agents that will further help in designing potent lead molecules.

Alkylating Agents, the Road Less Traversed, Changing Anticancer Therapy.

Cancer is considered one of the gruelling challenges and poses a grave health hazard across the globe. According to the International Agency for Research on Cancer (IARC), new cancer cases increased to 18.1 million in 2018, with 9.6 million deaths, bringing the global cancer rate to 23.6 million by 2030. In 1942, the discovery of nitrogen mustard as an alkylating agent was a tremendous breakthrough in cancer chemotherapy. It acts by binding to the DNA, and creating cross linkages between the two strands, leading to halt of DNA replication and eventual cell death. Nitrogen lone pairs of 'nitrogen mustard' produce an intermediate 'aziridinium ion' at the molecular level, which is very reactive towards DNA of tumour cells, resulting in multiple side effects with therapeutic consequences. Owing to its high reactivity and peripheral cytotoxicity, several improvements have been made with structural modifications for the past 75 years to enhance its efficacy and improve the direct transport of drugs to the tumour cells. Alkylating agents were among the first non-hormonal substances proven to be active against malignant cells and also the most valuable cytotoxic therapies available for the treatment of leukaemia and lymphoma patients. This review focus on the versatile use of alkylating agents and the Structure Activity Relationship (SAR) of each class of these compounds. This could provide an understanding for design and synthesis of new alkylating agents having enhanced target specificity and adequate bioavailability.

HPTLC densitometric evaluation of tissue culture extracts of Nothapodytes foetida compared to conventional extracts for camptothecin content and antimicrobial activity.

Tissue culture technique is becoming popular because of its well-known ability to enhance the content of secondary metabolites in plants. Callus tissue cultures of Nothapodytes foetida were developed using 250 different medium compositions to optimize this procedure. Methanolic extracts of callus (MEC) and of various parts of N. foetida were comparatively analyzed for camptothecin content, and a high performance thin layer chromatography method was developed for its quantitation. Chloroform-ethylacetate-methanol (4 : 5 : 0.5 v/v) was used as the mobile phase. The method was validated for linearity, precision (interday and intraday), repeatability, limit of detection (LOD), limit of quantitation (LOQ), and accuracy. The relationship between the concentration of standard solutions and the peak response was linear within the range of 80 to 480 ng/spot with a correlation coefficient of 0.998 +/- 0.020. Instrumental precision was evaluated as 0.54 (% CV). Repeatability of sample and standard were estimated to be 1.08 and 1.01 (% CV), and LOD and LOQ were found to be 40 and 80 ng/spot, respectively. The accuracy of the method was checked out by a recovery study and the average percentage recovery was calculated as being 99.13 %. The methanolic extract of callus grown in tissue culture with medium composition picloram + thidiazuron + gibberellic acid (1 : 1 : 4; MEC-PTG) showed a higher percentage of camptothecin (5.74 % w/v) than the methanolic extract of fruits (3.56 % w/w), leaves (1.56 % w/w), stem (1.19 % w/w), and root (1.11 % w/w). The results of the antimicrobial screening indicate that MEC-PTG exhibited maximum activity against all microorganisms. Among the fungi tested, MEC-PTG showed maximum activity against A. niger and C. albicans (MIC value 10 microg/mL) whereas among bacteria strains, its activity was highest against B. subtilis and S. lutea (MIC 20 microg/mL).

Study on mechanism for amorphous drug stabilization using gelucire 50/13.

Methods of preparation and application of amorphous form are well established but it is equally important to note that devitrification of amorphous drugs has limited their applications. Present study was performed to investigate mechanism for amorphous drug stabilization using Gelucire in comparison with polyvinylpyrrolidone (PVP). Etoricoxib and celecoxib were taken as model drugs for this study, as etoricoxib has only proton accepting site for hydrogen bonding in comparison with celecoxib, which has both proton accepting and donating site. Solid dispersion of celecoxib with polyvinylpyrrolidone and Gelucire was prepared by spray drying and melt-granulation technique respectively. X-ray powder diffractometry and differential scanning calorimetry were used to study the physical state of the drug. Dissolution studies were performed to differentiate dissolution performance. Stability study samples were evaluated for physical state of the drug and dissolution performance. An IR study in correlation with molecular modeling was carried out to study the mechanism for stabilization. Dissolution of melt-granulation of amorphous celecoxib was improved significantly as compared to amorphous celecoxib and Celecoxib-PVP solid dispersion. Melt-granulation with lipid seemed to be more dominant than amorphization of drug for improving dissolution. Stability data revealed that PVP was significantly advantageous for amorphous form stabilization whereas Gelucire failed in case of Celecoxib. In contrast to this, our previous study revealed the stabilization ability of Gelucire for amorphous etoricoxib. Molecular modeling and IR studies revealed that H-bonding was predominant mechanism for stabilization. Out of two proposed mechanism for amorphous drug stabilization by lipids, H-bonding ability is more dominant than immobilization of molecule in lipid matrix.

Amelioration of hepatotoxicity by biocleavable aminothiol chimeras of isoniazid: Design, synthesis, kinetics and pharmacological evaluation.

AIM: To overcome the hazardous effects on liver caused by long-term use of antitubercular agent isoniazid (INH) by developing a novel hepatoprotective prodrug strategy by conjugating INH with aminothiols as antioxidant promoities for probable synergistic effect. METHODS: INH was conjugated with N-acetyl cysteine (NAC) and N-(2)-mercaptopropionyl glycine using the Schotten-Baumann reaction and with L-methionine using Boc-anhydride through a biocleavable amide linkage. Synthesized prodrugs were characterized by spectral analysis, and in vitro and in vivo release studies were carried out using HPLC. Their hepatoprotective potential was evaluated in male Wistar rats by performing liver function tests, measuring markers of oxidative stress and carrying out histopathology studies. RESULTS: Prodrugs were found to be stable in acidic (pH 1.2) and basic (pH 7.4) buffers and in rat stomach homogenates, whereas they were hydrolysed significantly (59.43%-94.93%) in intestinal homogenates over a period of 6 h. Upon oral administration of prodrug NI to rats, 52.4%-61.3% INH and 47.4%-56.8% of NAC were recovered in blood in 8-10 h. Urine and faeces samples pooled over a period of 24 h exhibited 1.3%-2.5% and 0.94%-0.9% of NAC, respectively, without any presence of intact NI or INH. Prodrugs were biologically evaluated for hepatoprotective activity. All the prodrugs were effective in abating oxidative stress and re-establishing the normal hepatic physiology. The effect of prodrug of INH with NAC in restoring the levels of the enzymes superoxide dismutase and glutathione peroxidase and abrogating liver damage was noteworthy especially. CONCLUSION: The findings of this investigation demonstrated that the reported prodrugs can add safety and efficacy to future clinical protocols of tuberculosis treatment.

Marker-based standardization and investigation of nutraceutical potential of Indian propolis.

OBJECTIVE: Propolis, a resinous material collected by honey bees from various plants, has been explored globally for its medicinal and nutritional properties. However, research over Indian propolis is at infancy. This study was designed to investigate nutraceutical potential of Indian propolis. METHODS: In the present study, propolis extract was standardized with respect to markers caffeic acid phenethyl ester, caffeic acid, galangin, luteolin, curcumin, apigenin, pinocembrin and quercetin by new high-performance thin-layer chromatographic (HPTLC) methods. The physico-chemical analysis, residues analysis and in vitro antioxidant activity analysis were performed. Nutraceutical value was examined in terms of fats, fibers, minerals, proteins, polysaccharides, total carbohydrates, and energy value. RESULTS: The developed HPTLC methods were found to be simple, reliable accurate, and the validation parameters were within the limits of the International Council for Harmonization of Technical Requirements for Pharmaceuticals for Human Use guidelines. Macerated ethanolic extract of propolis (MEEP) was found to have polyphenolic content of (20.99 ± 0.24) mg/g and flavonoids content of (8.39 ± 0.04) mg/g. MEEP was found to comprise of (283.33 ± 51.31) g/kg fats, (30.07 ± 7.30) g/kg fibers, (102.56 ± 2.84) g/kg proteins and (389.36 ± 57.50) g/kg carbohydrate with a calorie value of (38 409.33 ± 6 169.80) kJ/kg. It was found that Indian propolis exhibited high nutraceutical value and showed absence of pesticides and heavy metals. The MEEP showed in vitro antioxidant activity with inhibitory concentration of (12.24 ± 4.64) µg/mL. CONCLUSION: The present work explores Indian propolis as a potential nutritious candidate. The proposed analytical methods can be applied in future screening of the quality of Indian propolis.

The ICH guidance in practice: stress degradation studies on stavudine and development of a validated specific stability-indicating HPTLC assay method.

A sensitive, selective, precise, and stability-indicating high-performance thin-layer chromatographic (HPTLC) method for the analysis of stavudine both as a bulk drug and in formulations is developed and validated. The solvent system consisted of toluene-methanol-chloroform-acetone (7.0:3.0:1.0:1.0, v/v/v/v). Densitometric analysis of stavudine is carried out in the absorbance mode at 270 nm. This system is found to give compact spots for stavudine (retention factor value of 0.45 +/- 0.05) following development of chromatoplates with the mobile phase. Stavudine is subjected to acid and alkali hydrolysis, oxidation, dry-heat and wet-heat treatment, and photo and UV degradation. The drug undergoes degradation under acidic and basic conditions, oxidation, and wet-heat degradation. Linearity is found to be in the range of 30-1000 ng/spot with a significantly high value of correlation coefficient. The linear regression analysis data for the calibration plots show a good linear relationship with r2 = 0.9997 +/- 0.05 in the working concentration range of 300 to 1000 ng/spot. The mean value of slope and intercept are 0.10 +/- 0.06 and 22.12 +/- 1.08, respectively. The method is validated for precision, robustness, and recovery. The limits of detection and quantitation are 10 and 30 ng/spot, respectively. The proposed HPTLC method is utilized to investigate the kinetics of the acid degradation process. Arrhenius plot is constructed and activation energy is calculated.

Synthesis, beta-adrenergic blocking activity and beta-receptor binding affinities of 1-substituted-3-(2-isopropyl-5-methyl-phenoxy)-propan-2-ol oxalates.

The compounds 1-isopropylamino-3-(2-isopropyl-5-methyl-phenoxy)-propan-2-ol oxalate (5) and 1-tert-butylamino-3-(2-isopropyl-5-methyl-phenoxy)-propan-2-ol oxalate (6) were synthesized from thymol (1), a naturally occurring agent in Thymus vulgaris L. Pharmacological evaluation of 5 and 6 were carried out using mouse ECG and isolated rat uterus models. Pretreatment of 5 (100 microg/kg, i.v.) and 6 (50 microg/kg, i.v.) antagonized isoprenaline (2 microg/kg, i.v.) induced tachycardia, similar to that of atenolol (CAS 29122-68-7, 20 microg/kg, i.v.) pretreatment in mouse ECG experiments as measured by R-R interval. Pretreatment of 5 and 6 blocked isoprenaline and adrenaline induced relaxation of isolated rat uterus (unprimed). Also the compounds 5 and 6 were subjected to in vitro beta1- and beta2-adrenergic receptor binding assay using turkey erythrocyte membrane (beta1) and lung homogenate of rats (beta2). Both 5 and 6 showed beta-adrenergic receptor affinity comparable with that of propranolol (propranolol hydrochloride, CAS 318-98-9) with out selectivity to any one beta-adrenergic receptor. These results suggest that both the compounds possess non-selective beta-adrenergic blocking activity, with the tert-butyl derivative 6 being more active than the isopropyl derivative 5.

Application of HPLC for the simultaneous determination of aceclofenac, paracetamol and tramadol hydrochloride in pharmaceutical dosage form.

A simple, precise and accurate reversed-phase liquid chromatographic method has been developed for the simultaneous estimation of aceclofenac (ACF), paracetamol (PCM) and tramadol hydrochloride (TRM) in pharmaceutical dosage form. The chromatographic separation was achieved on a HiQ-Sil™ HS C18 column (250×4.6 mm i.d., 5 µm particle size), kromatek analytical column at ambient temperature. The mobile phase consisted of 40: 60 (v/v); phosphate buffer (pH 6.0): methanol. The flow rate was set to 1.0 mL min(-1) and UV detection was carried out at 270 nm. The retention time (t(R)) for ACF, PCM and TRM were found to be 14.567 ± 0.02, 3.133 ± 0.01 and 7.858 ± 0.02 min, respectively. The validation of the proposed method was carried out for linearity, precision, robustness, limit of detection, limit of quantitation, speci city, accuracy and system suitability. The linear dynamic ranges were from 40-160 µg mL(-1) for ACF, 130-520 µg mL(-1) for PCM and 15-60 µg mL(-1) for TRM. The developed method can be used for routine quality control analysis of titled drugs in pharmaceutical dosage form.

Chromatographic determination of itopride hydrochloride in the presence of its degradation products.

Two sensitive and reproducible methods are described for the quantitative determination of itopride hydrochloride (IH) in the presence of its degradation products. The first method is based on HPLC separation on a reversed phase Kromasil column [C18 (5-microm, 25 cm x 4.6 mm, ID)] at ambient temperature using a mobile phase consisting of methanol and water (70:30, v/v) adjusted to pH 4.0 with orthophosphoric acid with UV detection at 258 nm. The flow rate was 1.0 mL per min with an average operating pressure of 180 kg/cm2. The second method is based on HPTLC separation on silica gel 60 F254 using toluene:methanol:chloroform:10% ammonia (5.0:3.0:6.0:0.1, v/v/v/v) as mobile phase at 270 nm. The analysis of variance (ANOVA) and Student's t-test were applied to correlate the results of IH determination in dosage form by means of HPLC and HPTLC methods. The drug was subjected to acid and alkali hydrolysis, oxidation, dry heat, wet heat treatment, UV, and photodegradation. The proposed HPLC method was utilized to investigate the kinetics of the acidic, alkaline, and oxidative degradation processes at different temperatures and the apparent pseudo-first-order rate constant, half-life, and activation energy were calculated. In addition the pH-rate profile of degradation of IH in constant ionic strength buffer solutions in the pH range 2-11 was studied.