Agha Zeeshan Mirza

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.

Nanomedicine and drug delivery: a mini review

The field of nanotechnology now has pivotal roles in electronics, biology and medicine. Its application can be appraised, as it involves the materials to be designed at atomic and molecular level. Due to the advantage of their size, nanospheres have been shown to be robust drug delivery systems and may be useful for encapsulating drugs and enabling more precise targeting with a controlled release. In this review specifically, we highlight the recent advances of this technology for medicine and drug delivery systems.

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.

Determination of Tryptophan in Raw Materials, Rat Brain and Human Plasma by RP-HPLC Technique

This paper describes tryptophan (TRP) estimation in raw human plasma and rat brain by reversed-phase high-performance liquid chromatography (RP-HPLC). Estimation was carried out on a Purospher STAR C18 column using water-acetonitrile (90:10 v/v, at pH 2.7) mixture at a rate of 1.5 mL/min as mobile phase. Eluents were monitored at 273 nm by an ultraviolet detector. The method was linear (R(2) > 0.999), precise (intra-day and inter-day precision <2%) in the range of 0.25-20 µg/mL. The detection and quantification limits were 0.0144 µg/mL and 0.0437 µg/mL, respectively. In human plasma, Day 1 and Day 2 precision were 0.054-2.29% and 1.66-3.7%; whereas precisions in rat brain were 1.23-2.3% and 0.677-4.2%, respectively. The method was applied to study TRP level in human smokers and in arthritic rat brain. An efficient RP-HPLC method was developed for TRP determination that worked for clinical and research purposes.

A novel drug delivery system of gold nanorods with doxorubicin and study of drug release by single molecule spectroscopy

Abstract The work presented here describes the fabrication of a novel drug delivery system, which consists of gold nanorods and doxorubicin, with the attachment of thioctic acid and folic acid, for the targeted release of drug to cancer cells. Doxorubicin, the potent anticancer drug, is widely used to treat various cancers. Gold nanorods were functionalized chemically to generate active groups for the attachment of drug molecules and subsequently attached to folic acid. The resulting nanostructure was characterized by UV-visible-NIR spectrophotometry, TEM techniques, zeta potential measurement and subsequently used to target folate receptor-expressing cancers cells for the delivery of doxorubicin. We generated a release profile for the release of doxorubicin from the nanostructures in KB cells using single-molecule fluorescence intensity images and fluorescence lifetime images. The results indicated that the nanorods were able to enter the target cells because of the attachment of folic acid and used as a carriers for the targeted delivery of doxorubicin.

Simultaneous determination of antihistamine anti-allergic drugs, cetirizine, domperidone, chlorphenamine maleate, loratadine, meclizine and buclizine in pharmaceutical formulations, human serum and pharmacokinetics application

This article describes a new, accurate and highly specific high performance liquid chromatographic method with UV detection (HPLC-UV) for the simultaneous determination of cetirizine HCl (CZ), chlorphenamine maleate (CPM), loratadine (LTD), domperidone (DP), buclizine (BZ) and meclizine (MZ) in pharmaceutical dosage form and human serum, involving pyridoxine (PYD) as the internal standard. The mobile phase consists of heptane sulphonic acid salt buffer and acetonitrile, drawn at a flow rate of 1.0 mL min−1 using a symmetry C18 column with UV detection at 230 nm. The intraday and inter-day precision measurements showed coefficients of variation always less than one. The calibration curve was tested in the range of 10–2150 ng mL−1 and the correlation coefficient of >0.9990 in all cases was obtained. The averages of the absolute and relative recoveries were found to be in the range of 98 to 102%. Up to six antihistamines were separated in the same chromatogram with good resolution. The proposed HPLC method has reasonable applications in pharmaceutical tablet dosage form and pharmacokinetics studies.

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.

VALIDATED RP-HPLC METHOD FOR QUANTITATION OF GLIQUIDONE IN PHARMACEUTICAL FORMULATION AND HUMAN SERUM

ABSTRACT 1. A simple isocratic reversed phase high performance liquid chromatographic (HPLC) method using C18 column with ultraviolet detection at 225 nm has been described for quantitative determination of gliquidone in formulation and human serum. The system is operated at room temperature using a mobile phase consisting of methanol: water (90:10) adjusted to pH 3.50 with phosphoric acid with a flow rate of 1 mLmin -1 . Methylparaben is successfully used as an internal standard. The assay is reproducible, linear (concentration range of 0.60-25 -1μgmL ) with correlation coefficient of 0.9999 and accurate (99.23 to 102.78%). The intra and inter run precision results are 1.14 and 1.32%. The LOD and LOQ values are 0.03 and 0.6 μgmL -1 , respectively. There are no interfering peaks due to the excipients present in the pharmaceutical tablet. Thus, the proposed method is simple and suitable for the analysis of active ingredient in tablet dosage form and human serum. Key words : Gliquidone, methylparaben, UV detection, RP-HPLC, dosage formulation, method validation.