Farhan Ahmed Siddiqui

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 60u2006:u200640 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 10u2006000 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.

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.

New Method Development for Hydroxyzine Determination: Application in Stability Studies, Pharmaceutical Formulations, and Humane Serum

This article pertains to development and validation of a low cost, fast, sensitive, and accurate RP-HPLC method for quantitative analysis of HZ. A Hibar μBondapak C18 column as the stationary phase and acetonitrile:methanol:buffer (500:200:300) as the mobile phase were used to accomplish the separation, when drawn at a flow rate of 1.0 mL/min, with 235 nm as monitoring wavelength. Linearity was established by studying the drug over the concentration range of 10–10000 ng mL−1, correlation coefficient of r = 0.9993, drug recovery (97 to 102%), and high reproducibility in serum samples (less than 2.5% RSD) displayed excellent linearity, accuracy, and precision. Force degradation studies of the drug under various stress conditions (acid, base, oxidation, photo, and thermal) proved the stability indicating power of the method. Substantial method validation study was carried out inline with ICH guidelines and was applied successfully to quantify the amount of HZ in bulk, pharmaceutical formulations, and blood serum samples.

Determination of benzimidazoles in pharmaceuticals and human serum by high-performance liquid chromatography

ABSTRACT A liquid chromatographic method is described for the quantification of prednisolone, benzimidazoles, and preservatives using a C18 analytical column as stationary phase. The mobile phase was 30:70 methanol:pH 2.5 phosphate buffer at a flow rate of 1.0 mL min−1 with absorbance detection at 235 nm. The method was linear for concentrations ranged from 40–10,000 ng mL−1. Low values of coefficient of variance were obtained when samples were analyzed as replicates. Excellent recovery values were recorded in commercial products and fortified samples. International Conference of Harmonization protocols were employed to perform comprehensive method validation. The reported method has applications for pharmaceutical and serum samples.

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.

Concurrent Determination of Diltiazem, Lisinopril, Captopril, and Enalapril in Dosage Formulations and in Human Serum by Liquid Chromatographic Technique

The aim of this study was to develop an analytical method that can quantify diltiazem, lisinopril, captropil, and enalapril in pharmaceuticals dosage forms and biological fluids, as these drugs are co-administered drugs. For the determination of diltiazem and ACE inhibitors a novel, trouble-free, quick, isocratic high performance liquid chromatography method has been established. The ACE inhibitors, which were assayed alongside diltiazem, include lisinopril, captopril, and enalapril. These drugs were tested in bulk, dosage formulations, and human serum. The analytes were separated on Pruospher Star RP-18 endcapped (250 mm × 4.6 mm id), and the mobile phase composition was acetonitrile:methanol:water (5:45:50 v/v/v). The pH of the mobile phase was adjusted with ortho-phosphoric acid at 2.5. The flow rate was maintained at 1 mLmin−1 at room temperature (25°C). The maximum wavelength for the assay was 230 nm on a UV detector. ICH validation parameters were followed while validating the method. The selected concentration range for establishing the linearity for diltiazem was 2.5–25 µgmL−1, 20–200 µgmL−1 for lisinopril enalapril, and 30–300 µgmL−1 for captopril. This linearity range was best as was demonstrated by r2 ≥ 0.999 (n = 6).

CoMFA and CoMSIA studies on a series of fluroquinolone derivatives for potential anti-inflammatory activity

Three-dimensional quantitative structure–activity relationships using CoMFA and CoMSIA were developed for a series of 28 fluroquinolone derivatives for prediction of anti-inflammatory activity. QSAR models with high squared correlation coefficients of up to 0.962 for CoMFA, 0.989 for CoMSIA-I and 0.987 for CoMSIA-II were established. The robustness of the model was confirmed with the help of leave-one-out cross-validation having values of 0.554 for CoMFA, 0.6 for CoMSIA-I and 0.597 for CoMSIA-II, respectively. Theoretical results were in accordance with the experimental data. Developed models highlighted the importance of steric, electrostatic, hydrophobic and donor descriptors for anti-inflammatory activity.

In-Vitro drug-drug interaction studies of diltiazem with floroquinolones

ABSTRACT Diltiazem is an established cardiovascular drug mainly used for the management of hypertension specifically for the angina pectoris. Fluoroquinolones are widely prescribed against the treatment of severe infections. In vitro relations of diltiazem with fluoroquinolones (ciprofloxacin, levofloxacin, norfloxacin, and ofloxacin) were examined using spectrophotometric and separation techniques, i.e., RP-HPLC. Diltiazem’s availabilities were observed to be predisposed highly in the presence of fluoroquinolones. To investigate the mechanism of interaction in a variety of dissolution environments, i.e., simulating body environments with regard to pH on these interactions has been studied. Moreover, complex of diltiazem–fluoroquinolones were prepared and elucidated through IR spectroscopy and confirmed by computational molecular modeling. GRAPHICAL ABSTRACT