Hina Shamshad

A versatile approach for the functionalization of gold nanorods and nanoparticles

A robust functionalized procedure for gold nanorods (Au NR) with mercaptoundecanoic acid (MUA), which are assembled with nanoparticles, has been reported in the present work. The self-assembled nanostructures were characterized by UV–Vis-NIR spectrophotometer and transmission electron microscopy (TEM). Self-assembly procedures, governed by surface chemistry, indicated that chemical reactivity of nanomaterial may contribute in construction of potential nanoscale assemblies. These nanostructures have striking applications as single-molecule detection, plasmonics, and sensing.

Preparation and characterization of doxorubicin functionalized gold nanoparticles

In this paper, we have presented the demonstration of gold nanoparticles (Au NPs) functionalized with an anticancer drug, doxorubicin. Doxorubicin was assembled on gold via amino group. The reaction proceeded under mild acidic conditions. Au NPs could not be adsorbed on doxorubicin in alkaline solution because amino group was not protonated. However, under acidic conditions, protonation created a positively charged amino group thus adsorption was easier. The interaction between Au colloids and doxorubicin is believed to be electrostatic. High-resolution TEM was used for visualization of nanoparticles, which were found to retain their average size and shape. The method, demonstrated that doxorubicin could be attached to Au NPs in a controlled manner. Our research laid the foundation of a linking methodology through which hybrid multi drug and receptor labeled NPs could be created, which might serve as an alternative design for nanosized drug-delivery systems.

Spectrophotometric determination of gabapentin in pharmaceutical formulations using ninhydrin and π-acceptors

Simple, rapid and sensitive spectrophotometric procedures are developed for the analysis of gabapentin in pure form as well as in their pharmaceutical formulations. The methods are based on the reaction of gabapentin as n-electron donor with ninhydrin and pi-acceptors namely, 2,3,5,6-tetrachloro-1,4-benzoquinone, chloranilic acid, 2,3-dichloro-5,6-dicyano-1,4-benzoquinone, tetracyanoethylene and 7,7,8,8-tetracyanoquinodimethane. The obtained complexes were measured at 568, 230, 314, 304, 335 and 439 nm for ninhydrin, chloranil, Chloranilic acid, DDQ, TCNE and TCNQ respectively. The proposed procedures could be successfully applied to the determination of gabepentin with good recovery; percent ranged from 99.3 to 100.7 The association constants and free energy changes using Benesi-Hildebrand plots are also studied.

Analysis of metformin, glimepiride and pioglitazone in human serum and its application to pharmacokinetics

A robust method, for the chromatographic separation of three antidiabetic drugs viz metformin, pioglitazone and glimepiride using an isocratic reversed phase high-performance liquid chromatographic (HPLC) system having ultraviolet detection at 254 nm is presented in this paper. The method was developed in human serum and dosage formulation with high-quality chromatographic separation between the drug peaks by using a stainless steel analytical column Nucleosil, C18 (10 micron, 25 × 0.46 cm). The system was operated at room temperature using a mobile phase consisting of acetonitrile, phosphate buffer (pH 4.3) in the ratio of 60 : 40 v/v at a flow rate of 1 mL min−1. The parametric statistics, i.e., correlation coefficient of 0.999 was assessed for all the drugs having linearity over the tested concentration range (10 to 10 000 ng mL−1) in human serum. The accuracy and the relative standard deviations of samples for six replicate measurements were not less than 97% and greater than 2%, respectively. The proposed method was validated for selectivity, linearity, accuracy, and precision according to the International Conference on Harmonization (ICH). The method is applicable for the quality control of the mentioned drugs in raw material, bulk drug, and pharmaceutical formulations as well as in human serum.

Drug interaction studies of gliquidone with fexofenadine, cetirizine, and levocetirizine

Controlling blood sugar levels is crucial for diabetic patients and is managed through administration of drugs such as gliquidone. Coadministration of antidiabetic drugs with H1-receptor antagonists is common but is also a source of concern due to potential coadministered drug interaction, especially in patients prone to allergic disorders. In this work, we describe in vitro drug interactions of gliquidone with commonly coadministered H1-receptor antagonists (fexofenadine hydrochloride, cetirizine dihydrochloride, and levocetirizine dihydrochloride). These studies were performed at 37°C in different pH environments simulating human body compartments using UV spectrophotometry and high performance liquid chromatography (HPLC). It was observed that the percentage availability values of gliquidone and H1-receptor antagonists were not affected in the presence of each other. No significant difference between gliquidone and H1-receptor antagonists and no remarkable changes in availability values were observed when these interactions were studied using UV–visible and HPLC techniques. This study thus supports the safe coadministration of gliquidone and H1-receptor blockers as an effective diabetic health management regimen.

A combined 3D-QSAR and docking studies for the In-silico prediction of HIV-protease inhibitors

BackgroundTremendous research from last twenty years has been pursued to cure human life against HIV virus. A large number of HIV protease inhibitors are in clinical trials but still it is an interesting target for researchers due to the viral ability to get mutated. Mutated viral strains led the drug ineffective but still used to increase the life span of HIV patients.ResultsIn the present work, 3D-QSAR and docking studies were performed on a series of Danuravir derivatives, the most potent HIV- protease inhibitor known so far. Combined study of 3D-QSAR was applied for Danuravir derivatives using ligand-based and receptor-based protocols and generated models were compared. The results were in good agreement with the experimental results. Additionally, docking analysis of most active 32 and least active 46 compounds into wild type and mutated protein structures further verified our results. The 3D-QSAR and docking results revealed that compound 32 bind efficiently to the wild and mutated protein whereas, sufficient interactions were lost in compound 46.ConclusionThe combination of two computational techniques would helped to make a clear decision that compound 32 with well inhibitory activity bind more efficiently within the binding pocket even in case of mutant virus whereas compound 46 lost its interactions on mutation and marked as least active compound of the series. This is all due to the presence or absence of substituents on core structure, evaluated by 3D-QSAR studies. This set of information could be used to design highly potent drug candidates for both wild and mutated form of viruses.

A RP-HPLC METHOD FOR THE SIMULTANEOUS DETERMINATION OF DILTIAZEM AND QUINOLONES IN BULK, FORMULATIONS AND HUMAN SERUM

High Performance Liquid Chromatographic method was developed and applied for the simultaneous determination of diltiazem and fluoroquinolones in bulk, pharmaceutical formulations and human serum in presence of caffeine as internal standard. A Hiber®, RP-18 column was used with mobile phase consisting of acetonitrile:methanol:water (30:20:50 v/v, pH 3.6) and quantitative evaluation was performed at 230 nm. Suitability of this method for the quantitative determination of the drugs was proved by validation in accordance with the requirements laid down by International Conference on Harmonization (ICH) guidelines.The method was selective, precise, accurate and can be used for routine analysis of pharmaceutical preparations, quality control and clinical laboratories.

Spectroscopic characterization of in vitro interactions of cetirizine and NSAIDS

BackgroundCetirizine (anti-allergy agent) and non-steroidal anti-inflammatory drugs (NSAIDs; anti-inflammatory agents) are co-administered drugs. Cetirizine, a P-glycopretein substrate may be affected by the use of NSAIDs. In the present work, quantification of cetirizine in the presence of commonly co-administered NSAIDs such as diclofenac sodium, ibuprofen, flurbiprofen, tiaprofenac acid, meloxicam and mefenamic acid were studied using the RP-HPLC technique.MethodsA high-throughput HPLC method for the analysis of cetirizine was developed, validated in the presence of NSAIDs and was further used to study the interactions of cetirizine in the presence of NSAIDs at four different pH levels. Purospher Star, C18 column (5 μm, 25 cm × 0.46 cm) with a mobile phase of methanol/water (90:10 v/v, pH adjusted to 3.5) at a flow rate of 1.0 mL/min and a wavelength of 240 nm was used.ResultsThe synthesis of cetirizine in the presence of NSAIDs was carried out, and complexes were characterized using infrared (IR) and nuclear magnetic resonance (NMR) techniques. The method was found to be applicable in serum and was found useful for therapeutic purposes. The differences in availabilities of cetirizine with NSAIDs at three pH levels clearly indicated the interactions of afore mentioned drugs.ConclusionsThe findings suggested further studies on the co-administration of these two drugs simultaneously in order to know the pharmacokinetic and pharmacodynamic profiles of the drugs. It is highly recommended to have a suitable time lapse between the oral uses of these drugs.

Simultaneous Determination of Cetirizine, Atorvastatin, Simvastatin, Rosuvastatin or Pravastatin in Formulations and Human Serum by RP-HPLC

Abstract Present work was designed for the simultaneous determination of cetirizine in presence of atorvastatin, simvastatin, rosuvastatin or pravastatin using RP-HPLC method. The chromatographic separation achieved using mobile phase consisted of acetonitrile: water (75:25), monitored at 235 nm with a pH adjusted to 2.8. The linearity was assessed over the range of 2.5-100 µgmL-1 for all drugs. The applicability of the method was verified by the determination of cetirizine, atorvastatin, simvastatin, rosuvastatin and pravastatin in marketed formulations. The results of the method were validated statistically according to ICH guidelines. The recovery values for all the drugs in formulations were found to be 96-108 %. The parameters such as accuracy, precision, linearity, sensitivity (LOQ=0.01-0.07, LOD=0.003-0.02 µgmL-1) were found to be satisfactory. This method can be successfully used for the determination of these drugs in formulations and can be a useful tool for the routine analysis in laboratories.

Kinetic and Thermodynamic Spectrophotometric Technique to Estimate Gabapentin in Pharmaceutical Formulations using Ninhydrin

BackgroundSimple and sensitive spectrophotometric method is described based on the reaction of drug (gabapentin) with ninhydrin in pure form and in pharmaceutical preparations.MethodsComplex formed during this reaction is measured at 575 nm as a function of time. Kinetic study involve initial-rate, rate-constant and fixed-time (80 minutes) procedures to determine the concentration of the drug.ResultsDrug was studied in the concentration range of 10-30 ?gmL-1 showing correlation coefficient 0.9997, 0.9970 and 0.9990 for initial rate, rate constant and fixed time respectively. Limit of detection (LOD) and limit of quantification (LOQ) was found to be 0.13 and 0.04 nana grams respectively. The variables affecting the reactions were optimized and the developed method was validated according to ICH guidelines.ConclusionThe proposed method has been efficiently applied to the estimation of gabapentin in pharmaceutical formulation with first-class recovery (98.3-101.4%). Thermodynamic parameters were studied i.e., association constants and standard free energy changes were determined by Benesi?Hildebrand equation while, Gibbs free energy change for the complex was also estimated.