Development of a Method for the Determination of Pyrimethamine Concentrations in Feeds by Ion-Pairing High-Performance Liquid Chromatography

2002 ◽  
Vol 65 (4) ◽  
pp. 688-691 ◽  
Author(s):  
P. S. GONG ◽  
S. L. JENG ◽  
Y. F. HSU ◽  
C. C. LIN ◽  
S. Y. LIN

An ion-pairing reversed-phase high-performance liquid chromatography (HPLC) method with diode array detection at 280 nm was developed to determine pyrimethamine concentrations in feed for laying hens. Pyrimethamine was extracted with a mixture of 5% isobutanol and 95% benzene, and the extract was cleaned up on an alumina column. The drug was eluted from an Intersil ODS-3V column (250 by 4.6 mm) with a mixture of 25% acetonitrile and 75% water (vol/vol) containing 0.01 M tetramethylammonium chloride as an ion-pairing agent and adjusted with acetic acid to pH 3.5. The flow rate was 1.0 ml/min. Mean recovery of pyrimethamine from supplemented feeds at concentrations of 2, 4, and 5 μg/g of feed were 100.5, 103.5, and 100.8%, respectively. Precision within a day ranged from 4.3 to 7.0% for the three concentrations, and day-to-day precision was 5.3% for feed supplemented at a concentration of 4 μg/g. No chromatographic interference was detected from other 2,4-diaminopyrimidine compounds or other major drugs used in poultry.

2020 ◽  
Vol 20 (13) ◽  
pp. 1053-1059
Author(s):  
Mahmoud M. Sebaiy ◽  
Noha I. Ziedan

Background: Allergic diseases are considered as the major burden on public health with increased prevalence globally. Histamine H1-receptor antagonists are the foremost commonly used drugs in the treatment of allergic disorders. The target drug in this study, loratadine, belongs to this class of drugs and its biometabolite desloratadine which is also a non-sedating H1 receptor antagonist with anti-histaminic activity being 2.5 to 4 times greater than loratadine. This study aimed to develop and validate a novel isocratic Reversed-phase High-Performance Liquid Chromatography (RP-HPLC) method for rapid and simultaneous separation and determination of loratadine and its metabolite, desloratadine in human plasma. Methods: The drug extraction method from plasma was based on protein precipitation technique. The separation was carried out on a Thermo Scientific BDS Hypersil C18 column (5μm, 250 x 4.60 mm) in a mobile phase of MeOH: 0.025M KH2PO4 adjusted to pH 3.50 using orthophosphoric acid (85: 15, v/v) at an ambient temperature. The flow rate was maintained at 1 mL/min and maximum absorption was measured using the PDA detector at 248 nm. Results: The retention times of loratadine and desloratadine in plasma samples were recorded to be 4.10 and 5.08 minutes, respectively, indicating a short analysis time. Limits of detection were found to be 1.80 and 1.97 ng/mL for loratadine and desloratadine, respectively, showing a high degree of sensitivity of the method. The method was then validated according to FDA guidelines for the determination of the two analytes in human plasma. Conclusion: The results obtained indicate that the proposed method is rapid, sensitive in the nanogram range, accurate, selective, robust and reproducible compared to other reported methods.


Author(s):  
Bijithra Cholaraja ◽  
Shanmugasundaram P ◽  
Ragan G ◽  
Sankar Ask ◽  
Sumithra M

ABSTRACTObjective: To development and validation of a reversed-phase high-performance liquid chromatography (RP-HPLC) for the determination of modafinilin bulk and pharmaceutical dosage forms.Methods: A simple, precise, rapid, and accurate RP-HPLC method was developed for the estimation of modafinil in bulk and pharmaceutical dosageforms. Xterra RP 18 (250 mm × 4.6 mm, 5 µ particle size) with a mobile phase consisting of methanol:water 70:30 V/V was used. The flow rate1.0 ml/min and the effluents were monitored at 260 nm. The retention time and recovery time was 12 minutes. The detector response was linear inthe concentration of 10-50 µg/ml. The respective linear regression equation being Y=452.1x+65237. The limit of detection and limit of quantificationwere 4.547 and 1.377 mcg, respectively. The method was validated by determining its accuracy, precision, and system suitability.Result: The objective of the present work is to develop simple, precise, and reliable HPLC method for the analysis of modafinil in bulk andpharmaceutical dosage forms. This is achieved using the most commonly employed Xterra RP 18 (250 mm × 4.6 mm, 5 μ particle size) columndetection at 260 nm. The present method was validated according to ICH guidelines.Conclusion: In this study, a simple, fast and reliable HPLC method was developed and validated for the determination of modafinil in pharmaceuticalformulations.Keywords: Modafinil, Reversed-phase high-performance liquid chromatography, Estimation, ICH guidelines, Tablets. 


2012 ◽  
Vol 95 (4) ◽  
pp. 1064-1068 ◽  
Author(s):  
Mohammed H Mehanna ◽  
Abdel M Motawaa ◽  
Magda W Samaha

Abstract A reliable and sensitive HPLC method was developed for the quantitation of tadalafil transdermal permeation through human skin. An RP column with UV detection at 290 nm was used for chromatographic separation at ambient temperature. The mobile phase was acetonitrile–water containing 20 mM pH 7 phosphate buffer (35/65, v/v) with a flow rate of 1.0 mL/min. The LOQ achieved was 1 ng/mL, and the calibration curve showed good linearity over the concentration range of 5–2000 ng/mL for tadalafil, with a determination coefficient (R2) of 0.998. The RSD values of intraday and interday analyses were all within 7%. Parameters of validation proved the precision of the method; this validated method was applied for the determination of tadalafil in transdermal permeation and drug deposition in human skin studies.


Author(s):  
Srinivasan Ms

Objective: A precise, accurate, simple, and gradient reversed-phase high-performance liquid chromatography (HPLC) method was adapted for the determination of abacavir sulfate (ABV) in combination with lamivudine (LMV) having tablet formulations simultaneously. This method developed has been validated as per the guidelines of ICH.Method: Waters HPLC has been used in the method with a column named Zorbax C18 with the dimensions as 4.6 nm×150 mm, 3.5 μm. Phosphate buffer (PH - 3.9) was used as Eluent - A, Eluent - B was methanol, and water and methanol (50:50 v/v) were utilized as diluents. The rate of flow was 1.5 ml/min.Results: The wavelength of detection has been detected at about 270 nm. Linearity ranges of ABV and LMV were 88–266 μg/ml and 38–116 μg/ml, respectively. Retention times of ABV (3.66 min) and LMV (10.71 min) were determined. The values of the study of percentage recovery of ABV and LMV were determined to be within 98.3–99.2%.Conclusion: The estimation of ABV and LMV in all pharmaceutical dosage forms could be performed successfully by employing this method.


Author(s):  
B G Keevil ◽  
W K Wong

A high-performance liquid chromatography (HPLC) method for the determination of sweat chloride was developed and evaluated. This method is capable of measuring chloride ion in sweat eluates with an analytical working range from 0·5 mmol/L to 6 mmol/L (15 to 180 mmol/L in undiluted sweat samples). Precision studies showed that at the levels of 1 mmol/L, 2·5 mmol/L and 3·5 mmol/L, the within batch coefficients of variation were 1·26%, 0·88% and 0·43%, respectively, and the between batch coefficients of variation were 1·31%, 1·75% and 1·07%, respectively. The minimum detection limit was 0·5 mmol/L. This method correlated well with the ion-selective electrode (ISE) method currently in use.


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