United Biotechnologies

Karachi, Pakistan

United Biotechnologies

Karachi, Pakistan
SEARCH FILTERS
Time filter
Source Type

Sultana N.,United Biotechnologies | Arayne M.S.,United Biotechnologies | Khan M.M.,University of Karachi | Saleem D.M.,University of Karachi | Mirza A.Z.,University of Karachi
Journal of Chromatographic Science | Year: 2012

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 (R2 > 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 RPHPLC method was developed for TRP determination that worked for clinical and research purposes. © The Author [2012].


Sultana N.,United Biotechnologies | Arayne M.S.,United Biotechnologies | Waheed A.,University of Karachi
Journal of the Chilean Chemical Society | Year: 2011

Verapamil, a calcium channel blocker, is classified as a class IV anti-arrhythmic agent. It is used in the treatment of hypertension, as an important therapeutic agent for angina pectoris, ischemic heart disease, hypertension and hypertrophic cardiomyopathy. Many in-vivo studies have been carried out to find out the effects on concurrent use of calcium channel blocker with various groups of drugs. In the present paper an in-vitro approach was adapted to study the interaction of verapamil with commonly administered fluoroquinolones i.e. ciprofloxacin, levofloxacin, norfloxacin and sparfloxacin. The interaction studies were carried out in different simulated body fluids pH ranges from 1-9 at 37 °C. To perform these studies first-derivative UV spectrophotometric (using zero-crossing technique) and simultaneous RP-HPLC methods were developed and validated. HPLC analysis was conducted on Shim-pack CLC-ODS (6.0 X 150 mm) column. The mobile phase constituted of acetonitrile: water (45:55), whose pH was adjusted to 2.8 and pumped at a flow rate of 1.2 mL min -1 at 230 nm. The results obtained from both methodologies indicated that the availability of verapamil was not affected by simultaneous administration of fluoroquinolones. Hence the two drugs could be safely administered concomitantly.


Najma S.,United Biotechnologies | Arayne M.S.,United Biotechnologies | Safila N.,Hamdard University
Chinese Journal of Chemistry | Year: 2011

Lisinopril is found to be useful in hypertension and statins as cholesterol lowering drug. Present work was designed for the simultaneous determination of lisinopril in presence of pravastatin, atorvastatin, and rosuvastatin using RP-HPLC method. A Purospher star C18 (5 μm, 25 × 0.46 cm) column was used with mobile phase consisting of acetonitrile:water (60:40 V/V, pH 3.0) with flow rate of 1.0 mL·min-1 and the quantitative evaluation was performed at 225 nm. The retention time of lisinopril was 2.0 min and for pravastatin, rosuvastatin and atorvastatin was found to be 3.1, 4.5 and 8.3 min respectively. 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. Application of the suggested procedures were successfully applied to the determination of these compounds in active pharmaceutical ingredient and in pharmaceutical preparations, with high percentage of recovery, good accuracy and precision. Copyright © 2011 SIOC, CAS, Shanghai & WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Sultana N.,United Biotechnologies | Muhammad S.A.,United Biotechnologies | Khan M.M.,Jinnah Medical and Dental College | Nawaz M.,United Arab Emirates University
Chinese Journal of Chemistry | Year: 2011

Leflunomide is a leading drug for the treatment of rheumatoid arthritis. The principle aim of this study was to develop and validate an RP-HPLC method for the determination of leflunomide in bulk and pharmaceutical dosage form using diclofenac sodium as an internal standard. For this purpose, chromatography was accomplished on a Purospher Start, C18 (5 (m, 12.5 cm× 0.46 cm) column at ambient temperature. Methanol:water (80:20, V/V) solvent system was selected as mobile phase, the pH of which was adjusted to 3.4 by ortho-phosphoric acid and delivered at a flow rate of 1.2 mL·min -1. Seperation of leflunomide and diclofenac sodium was carried out on a Purospher Start, C18 equipped with a UV-visible detector at 248 nm. The suitability of the method for the quantitative determination of the drugs is proven by validation in accordance with the requirements laid down by the International Conference on Harmonization (ICH) guidelines. The method was accurate (99.55%-100.03%), specific, linear (R2>0.999) and precise (intra-day precision 0.023%-0.93% and inter-day precision 0.26%-0.944%) in the range of 0.5-20 (g·mL-1. The minimum limit of detection and quantification in pharmaceutical formulation were 0.05 and 0.15 (g·mL-1, respectively. Thus the proposed method is simple, accurate, reproducible and suitable for the routine analysis of leflunomide in pharmaceutical formulations and was applied to study in vitro drug-metal interactions. The principle aim of this study was to develop and validate an RP-HPLC method for the determination of leflunomide in bulk and pharmaceutical dosage form using diclofenac sodium as an internal standard. The suitability of the method for the quantitative determination of the drugs is proven by validation in accordance with the requirements laid down by the International Conference on Harmonization (ICH) guidelines. Copyright © 2011 SIOC, CAS, Shanghai & WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Sultana N.,United Biotechnologies | Arayne M.S.,United Biotechnologies | Gul S.,University of Karachi | Akhtar M.,University of Karachi | Shamim S.,University of Karachi
Medicinal Chemistry Research | Year: 2012

Innovative, simple, economical, and rapid reverse phase HPLC method has been developed and validated for simultaneous determination of sparfloxacin (SPFX) and cimetidine, ranitidine, and famotidine (H 2 receptor antagonists) in bulk material, pharmaceutical formulations, and human serum. Chromatographic system was consisting of schemed HPLC system having UV detector set at 232 nm for cimetidine and, 250 nm for famotidine and ranitidine. Purospher STAR C 18 (250 × 4.6 mm, 5 μm) column was used, and the mobile phase (methanol, water and ACN 54:41:5 v/v/v pH 2.7 adjusted by phosphoric acid) was delivered at a flow rate of 1.0 ml min -1. The proposed method is specific, accurate (98.02-102.136%), precise (intra-day and inter-day variation 0.501-2.179%) and linear (R 2[0.999) with in the desired range 0.3125-25 μg ml -1 concentration. The detection limit and quantification limit were 0.009-0.084 and 0.030-0.255 μg ml -1, respectively. Paired t test was applied to verify the results. The anticipated method is applicable to routine analysis of SPFX and H 2 receptor antagonists in pharmaceutical formulations as well as in human serum samples. The proposed method is also applied to study interaction studies of SPFX with H receptor antagonists. © Springer Science+Business Media, LLC 2011.


Sultana N.,United Biotechnologies | Arayne M.S.,United Biotechnologies | Shah S.N.,University of Karachi | Shafi N.,University of Karachi | Naveed S.,Hamdard University
Journal of the Chinese Chemical Society | Year: 2010

Prazosin hydrochloride is the first developed selective antagonist for α1 - adrenoceptors, which is used as antihypertensive agent. Statins are used in the treatment of various types of hypercholesterolemia. In the present paper a simple, specific an accurate RP-HPLC method was developed and validated for the simultaneous determination of prazosin, atorvastatin, rosuvastatin and simvastatin in active and in dosage formulations. A nucleosil 100-10, C-18, 10μ column having 250 × 4.6 mmi.d. in isocratic mode, with mobile phase containing methanol:water:acetonitrile (70:20:10) adjusted to pH 2.5 ± 0.02 using orthophosphoric acid. The flow rate was 1 mLmin -1 and effluents were monitored at 240 nm. The % recovery for all the drugs in formulations was found to be 94-105%. The parameters such as accuracy (%RSD less than 2), precision (%RSD less than 2), linearity (>0.999) were found to be satisfactory. The presented method was applied without any interference of excepients for the determination of tablets. The proposed method due to its low LOQ, excellent accuracy, precision and selectivity could be used for routine quality control.


PubMed | United Biotechnologies
Type: Evaluation Studies | Journal: Journal of chromatographic science | Year: 2012

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 g/mL. The detection and quantification limits were 0.0144 g/mL and 0.0437 g/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.


Gul S.,Jinnah University for Women | Sultana N.,United Biotechnologies | Arayne M.S.,United Biotechnologies | Shamim S.,Dow University of Health Sciences | And 2 more authors.
Journal of Chemistry | Year: 2013

Four new metal complexes (S12-S15) of SPFX (third-generation quinolones) via heavy metals have been synthesized in good yield and characterized by physicochemical and spectroscopic methods including TLC, IR, NMR, and elemental analyses. Sparfloxacinato ligand binds with metals through pyridone and oxygen atom of carboxylic group. The biological actives of complexes have been tested against four Gram-positive and seven Gram-negative bacteria and six different fungi. Statistical analysis of antimicrobial data was done by one-way ANOVA, Dunnett's test; it was observed that S13, S14, and S15 were found to be most active complexes. Antifungal data confirm that all four synthesized complexes are most active and show significant activity against F. solani with respect to parent drug and none of complexes show activity against A. parasiticus, A. effuris, and S. cervicis. To study inhibitory effects of newly formed complexes, enzyme inhibition studies have been conducted against urease, α-chymotrypsin, and carbonic anhydrase. Enzymatic activity results of these complexes indicated them to be good inhibitors of urease enzyme while all complexes show mild activities against carbonic anhydrase enzyme. Further research may prove the promising role of these synthesized complexes as urease inhibitors. © 2013 Somia Gul et al.

Loading United Biotechnologies collaborators
Loading United Biotechnologies collaborators