Birendra Shrivastava

Design, synthesis and potential 6 Hz psychomotor seizure test activity of some novel 2-(substituted)-3-{[substituted]amino}quinazolin-4(3H)-one

Thirty new 2-(substituted)-3-{[substituted]amino}quinazolin-4(3H)-one were designed and synthesized keeping in view the structural requirement of pharmacophore and evaluated for anticonvulsant activity and neurotoxicity. The anticonvulsant activity of the titled compounds was assessed using the 6 Hz psychomotor seizure test. The most active compound of the series was 3-({(E)-[3-(4-chloro-3-methylphenoxy)phenyl]methylidene}amino)-2-phenylquinazolin-4(3H)-one PhQZ 7, which showed 100% protection (4/4, 0.5 h) and 75% protection (3/4, 0.25 h) at a dose of 100 mg/kg in mice. A computational study was carried out for calculation of pharmacophore pattern and prediction of pharmacokinetic properties. Titled compounds have also exhibited good binding properties with epilepsy molecular targets such as glutamate, GABA (A) delta and GABA (A) alpha-1 receptors, in Lamarckian genetic algorithm based flexible docking studies.

Hesperidin produces cardioprotective activity via PPAR-γ pathway in ischemic heart disease model in diabetic rats.

The present study investigated the effect of hesperidin, a natural flavonoid, in cardiac ischemia and reperfusion (I/R) injury in diabetic rats. Male Wistar rats with diabetes were divided into five groups and were orally administered saline once daily (IR-sham and IR-control), Hesperidin (100 mg/kg/day; IR-Hesperidin), GW9962 (PPAR-γ receptor antagonist), or combination of both for 14 days. On the 15th day, in the IR-control and IR-treatment groups, rats were subjected to left anterior descending (LAD) coronary artery occlusion for 45 minutes followed by a one-hour reperfusion. Haemodynamic parameters were recorded and rats were sacrificed; hearts were isolated for biochemical, histopathological, ultrastructural and immunohistochemistry. In the IR-control group, significant ventricular dysfunctions were observed along with enhanced expression of pro-apoptotic protein Bax. A decline in cardiac injury markers lactate dehydrogenase activity, CK-MB and increased content of thiobarbituric acid reactive substances, a marker of lipid peroxidation, and TNF-α were observed. Hesperidin pretreatment significantly improved mean arterial pressure, reduced left ventricular end-diastolic pressure, and improved both inotropic and lusitropic function of the heart (+LVdP/dt and –LVdP/dt) as compared to IR-control. Furthermore, hesperidin treatment significantly decreased the level of thiobarbituric acid reactive substances and reversed the activity of lactate dehydrogenase towards normal value. Hesperidin showed anti-apoptotic effects by upregulating Bcl-2 protein and decreasing Bax protein expression. Additionally, histopathological and ultrastructural studies reconfirmed the protective action of hesperidin. On the other hand, GW9662, selective PPAR-γ receptor antagonist, produced opposite effects and attenuated the hesperidin induced improvements. The study for the first time evidence the involvement of PPAR-γ pathway in the cardioprotective activity of hesperidin in I/R model in rats.

Risk management and statistical multivariate analysis approach for design and optimization of satranidazole nanoparticles

&NA; Rapidly evolving technical and regulatory landscapes of the pharmaceutical product development necessitates risk management with application of multivariate analysis using Process Analytical Technology (PAT) and Quality by Design (QbD). Poorly soluble, high dose drug, Satranidazole was optimally nanoprecipitated (SAT‐NP) employing principles of Formulation by Design (FbD). The potential risk factors influencing the critical quality attributes (CQA) of SAT‐NP were identified using Ishikawa diagram. Plackett‐Burman screening design was adopted to screen the eight critical formulation and process parameters influencing the mean particle size, zeta potential and dissolution efficiency at 30 min in pH 7.4 dissolution medium. Pareto charts (individual and cumulative) revealed three most critical factors influencing CQA of SAT‐NP viz. aqueous stabilizer (Polyvinyl alcohol), release modifier (Eudragit® S 100) and volume of aqueous phase. The levels of these three critical formulation attributes were optimized by FbD within established design space to minimize mean particle size, poly dispersity index, and maximize encapsulation efficiency of SAT‐NP. Lenths and Bayesian analysis along with mathematical modeling of results allowed identification and quantification of critical formulation attributes significantly active on the selected CQAs. The optimized SAT‐NP exhibited mean particle size; 216 nm, polydispersity index; 0.250, zeta potential; −3.75 mV and encapsulation efficiency; 78.3%. The product was lyophilized using mannitol to form readily redispersible powder. X‐ray diffraction analysis confirmed the conversion of crystalline SAT to amorphous form. In vitro release of SAT‐NP in gradually pH changing media showed <20% release in pH 1.2 and pH 6.8 in 5 h, while, complete release (>95%) in pH 7.4 in next 3 h, indicative of burst release after a lag time. This investigation demonstrated effective application of risk management and QbD tools in developing site‐specific release SAT‐NP by nanoprecipitation. Graphical abstract Figure. No caption available.

Hesperidin blunts streptozotocin-isoproternol induced myocardial toxicity in rats by altering of PPAR-γ receptor

Hesperidin has been shown to possess cardioprotective and anti-diabetic potential. Hitherto, its molecular mechanism on isoproterenol (ISO)-induced myocardial dysfunction in diabetes is still not explored. Hence, for the first time we sought to investigate whether hesperidin exerts any beneficial effect on the pathophysiology of myocardial infarction (MI) in diabetes through the PPAR-γ pathway by assessing a variety of indices e.g., apoptosis, hemodynamic, biochemical and histoarchitectural changes. Diabetes was induced by a single dose of STZ (50 mg/kg IP). Diabetic rats received either hesperidin (100 mg/kg/day orally), the PPAR-γ antagonist GW9662 (1 mg/kg/day IP), or both for 14 days with concurrent administration of ISO (85 mg/kg SC) on days 13 and 14. ISO-STZ rats resulted in severe myocardial dysfunction (decreased ±LVdP/dt and increased LVEDP). In addition, augmented myocardial thiobarbituric acid-reactive substances and serum troponin-I with a concomitant decrease in level of glutathione and activities of catalase, superoxide dismutase antioxidants with cardiac injury biomarkers creatine kinase-MB isoenzyme, lactate dehydrogenase were seen. Morphological studies of the ISO-STZ challenged myocardium exhibited severe necrosis, edema and inflammatory changes. In Western blot analysis, Bcl-2 and PPAR-γ expression were decreased where as Bax expression was significantly increased, suggesting role of apoptosis in myocardial dysfunction. Interestingly, hesperidin treatment positively modulated these parameters as validated by improved hemodynamic and left ventricular functions, fortified endogenous anti-oxidant defence system and improved structural integrity of the myocardium. However, significant effects were lowered in animals treated with hesperidin plus GW9662. Moreover, down-regulated PPAR-γ and Bcl-2 expressions in myocardial infarcted diabetic hearts were increased by hesperidin treatment. Hence, for the first time the present study suggests that, hesperidin reduces oxidative stress, apoptosis and improves cardiac function via the PPAR-γ pathway.

Dihydropyrimidinone-isatin hybrids as novel non-nucleoside HIV-1 reverse transcriptase inhibitors

A novel series of substituted N-(2-(2,3-dioxoindolin-1-yl)acetyl)-2-oxo-1,2,3,4-tetrahydropyrimidine-5-carboxamide was designed, synthesized and evaluated for in vitro Reverse Transcriptase (RT) inhibitory activity. This series is a combination of peculiar structural features from leading scaffolds of [(2-hydroxyethoxy)methyl]-6-(phenylthio)thymine (HEPT) and oxyindole. In vitro screening led to identification of two hybrids (9c and 9d) possessing higher RT inhibitory activity than the standard rilpivirine. Docking study was performed to study the binding orientations of synthesized hybrids towards RT enzyme.

Method Development and Validation for Determination of Febuxostatfrom Spiked Human Plasma Using RP-HPLC with UV Detection

A rapid, simple, selective, and specific reverse phase high performance liquid chromatography (RP-HPLC) method with UV detection (315 nm) was developed and validated for estimation of febuxostat from spiked human plasma. The analyte and internal standard (diclofenac) were extracted using LLE with diethyl ether. The chromatographic separation was performed on Shodex C-18-4E (5 μm;  mm) with a mobile phase comprised of methanol : acetate buffer pH 4, 20 mM (90 : 10 v/v), at a flow rate of 1 mL/min. Febuxostat was well resolved from plasma constituents and internal standard. The calibration curve was linear in the range of 250–8000 ng/mL. The heteroscedasticity was minimized by using weighted least square regression with weighing factor of . The intraday and interday %RSD was less than 15. Results of recovery studies prove the extraction efficiency. Stability data indicated that febuxostat was stable in plasma after three freeze thaw cycles and upon storage at −20°C for 30 days.

Mechanistic investigation of biopharmaceutic and pharmacokinetic characteristics of surface engineering of satranidazole nanocrystals

The designing of surface engineered nanocrystals for improved stability and bioavailability is a multivariate process depending on several critical formulation and process variables. The present investigation deals with formulation of stable nanocrystals of poorly soluble satranidazole (SAT) for improving dissolution rate and pharmacokinetic profiling. SAT has low polar surface area, high dose and dosing frequency. Based on goniometric and stability studies of formulations prepared with various stabilizers, a unique combination of Span 20 and HPMC E-5 was selected for detailed investigation. Lyophilization of SAT nanosuspension was explored with nine different cryoprotectants in varying amounts to obtain easily redispersible nanocrystals (SAT-NC). The mean particle size and zeta potential of SAT-NC were found to be 208.8nm and -41.3mV respectively. DSC and XRPD confirmed the crystalline state of SAT. In vitro release studies of SAT-NC showed almost complete dissolution within 20min in water. Extravascular, one compartment pharmacokinetic modeling of in vivo plasma concentration versus time studies in male Wistar rats revealed twofold increase in Cmax, and AUC0-∞. Method of residuals was employed to calculate rate of absorption Ka and lag time. Nanosizing with appropriate stabilizers and programmed processing conditions successfully produced SAT-NC with improved pharmaceutic and pharmacokinetic characteristics.

Development and In Vitro Evaluation of Ketoprofen Extended Release Pellets Using Powder Layering Technique in a Rotary Centrifugal Granulator

Powder layering technique was evaluated using laboratory scale centrifugal granulator instrument to prepare extended release pellet dosage form of ketoprofen. Ethyl cellulose and shellac polymers were used for drug layering and extended release coating in the same apparatus. Inert sugar spheres were intermittently treated with drug powder and binding solution. Combination of ethyl cellulose (45cps) and shellac was evaluated as binders at different levels (1:3 ratio, at 6%, 12%, 16% and 21%w/w polymer) for drug loading and for extended release coating (1:3 ratio at 2%, 4% and 7% w/w polymer). Pellets were evaluated for drug release study using paddle apparatus in pH 6.8 Phosphate buffer, 900ml at 100 rpm. Ethyl cellulose and shellac when used as binder during drug layering did not extend the ketoprofen release beyond 4h. However, coating of drug loaded pellets using ethyl cellulose and shellac resulted in extended release profile of ketoprofen for about 10h. Ethyl cellulose coating alone at a level of 3% w/w resulted in extended release profile. Coated pellets were evaluated for sphericity, Hardness-Friability Index and scanning electron microscopy. Scanning electron micrographs of the pellets showed a uniform coating of polymer on the core pellets substantiating the use of centrifugal granulator for extended release coating. Release pattern from the optimized batch was best explained by Higuchis model. The drug release pattern from the pellets was found to be Non-Fickian anomalous type, involving both diffusion and erosion mechanism. Accelerated stability study of the coated pellets filled in hard gelatin capsule was conducted for 3-month period and observed for the effect on drug release profile.