Separation and quantitation of jasmonic acid using HPTLC

A rapid, simple, and stringent protocol for the detection and quantitation of jasmonic acid (JA) is designed using high-performance thin-layer chromatography. Acidified culture filtrate of Lasiodiplodia theobromae is extracted with an equal volume of ethyl acetate and spotted on silica gel 60 F(254) foil using Linomat-5 spray-on applicator. Standard JA is also spotted either internally or adjacent to the sample, and the foils are developed with isopropanol-ammonia-water [10:1:1 (v/v)] as the mobile phase. A quantitative estimation of the separated JA is performed by measuring the absorbance at 295 nm in the reflective mode. The sensitivity of the method is improved by adding internal standard to obtain a detection limit of 1 microg. The limit of quantitation is found to be 80 microg with this method. The method is shown to have selectivity, accuracy, precision, and high sample throughput, making it useful for the routine analysis of JA in basic science and perfumery industries.     

Separation and quantitation of the four stereoisomers of itraconazole in pharmaceutical formulations by electrokinetic chromatography

The four stereoisomers of itraconazole were resolved for the first time by EKC using a CD as chiral selector. A study on the enantiomeric separation ability of different neutral CDs was carried out. Heptakis-2,3,6-tri-O-methyl-beta-CD was shown to provide the highest values for the enantiomeric resolution. The influence of some experimental conditions, such as pH, chiral selector concentration, and temperature, on the enantiomeric separation was also studied. The use of a 100 mM phosphate buffer (pH 2.5), 30 mM in heptakis-2,3,6-tri-O-methyl-beta-CD together with an applied voltage of 30 kV and a temperature of 20 degrees C enabled the separation of the enantiomers of itraconazole with high resolutions (Rs > 3.0). Finally, the method was validated and successfully applied to the quantitation of itraconazole in three pharmaceutical formulations.     

Separation of Fenoxaprop-p-ethyl Biodegradation Products by HPTLC

JPC – Journal of Planar Chromatography – Modern TLC -     

Separation and Determination of Nitroguanidine and Guanidine Nitrate by HPTLC

High-performance thin-layer chromatography has been used for separation and quantification of nitroguanidine and guanidine nitrate, for online and off-line quality control of synthesis. The compounds were separated on silica gel 60 F₂₅₄ layers with dioxane–tetrahydrofuran 1:1 (v/v), as mobile phase. UV detection was performed at 210 and 265 nm for guanidine nitrate and nitroguanidine, respectively. Quantitative analysis was performed by absorbance densitometry and use of peak area. Validation was performed taking into consideration the special features of the method.     

Separation and quantitation of oxprenolol in urine and pharmaceutical formulations by HPLC using a Chiralpak IC and UV detection

Abstract  

A stereoselective HPLC method has been developed for the simultaneous determination of oxprenolol enantiomers in urine and pharmaceutical products. Enantiomeric resolution of oxprenolol was achieved on cellulose tris(3,5-dichlorophenylcarbamate) immobilized onto a 5 μm spherical porous silica chiral stationary phase (CSP) known as Chiralpak IC with UV detection at 273 nm. The mobile phase consisted of n-hexane:isopropanol:triethylamine 70:30:0.1 (v/v/v) at a flow rate of 1.0 cm³/min. The method was validated for its linearity, accuracy, precision, and robustness. The calibration curves were linear over the range of 0.5–75 μg/cm³, with a detection limit of 0.1 μg/cm³ for each enantiomer. An average recovery of 99.0% and a mean relative standard deviation of 2.6% at 40.0 μg/cm³ for S-(−)- and R-(+)-enantiomers were obtained. The overall recoveries of oxprenolol enantiomers from pharmaceutical formulations were in the range 97.5–99.0%, with RSDs ranging from 0.6 to 0.8%. The mean extraction efficiency of oxprenolol from urine was in the range of 86.0–93.0% at 0.5–5 μg/cm³ for each enantiomer. The assay method proved to be suitable as a chiral quality control for oxprenolol formulations using HPLC and for therapeutic drug monitoring.     

Erratum to: Separation of Fenoxaprop-p-ethyl Biodegradation Products by HPTLC

JPC – Journal of Planar Chromatography – Modern TLC - The corresponding author of the article “Separation of Fenoxaprop-p-ethyl Biodegradation Products by HPTLC”, J. Planar...     

Two-Dimensional Separation of Some Amino Acids by HPTLC and Pressurized Planar Electrochromatography

JPC – Journal of Planar Chromatography – Modern TLC - Two-dimensional (2D) separation of eight amino acids has been achieved by HPTLC in the first dimension and pressurized planar...     

Separation of Sulfonylurea Herbicides and Determination of Bensulfuron-methyl Residues in Tapwater by HPTLC

JPC – Journal of Planar Chromatography – Modern TLC - In this work we have studied the separation of a mixture of the sulfonylurea herbicides (metsulfuron-methyl, chlorsulfuron,...     

Separation and quantitation of fatty acids by high-performance liquid chromatography

To facilitate the determination of the fatty acid composition of tissues and the investigation of fatty acid metabolism, we developed a method for the rapid separation by high-performance liquid chromatography and quantitation (by ultraviolet light absorption) of p-bromophenyl esters of fatty acids which vary in chain length from 10 to 22 carbon atoms. The utility of the method was demonstrated by evaluating the fatty acid composition of human uterine decidua vera tissue and human endometrial stromal cells that are maintained in monolayer culture.     

Estimation of L-dopa from Mucuna pruriens LINN and formulations containing M. pruriens by HPTLC method

A selective, precise, and accurate high-performance thin-layer chromatographic (HPTLC) method has been developed for the analysis of L-dopa in Mucuna pruriens seed extract and its formulations. The method involves densitometric evaluation of L-dopa after resolving it by HPTLC on silica gel plates with n-butanol-acetic acid-water (4.0+1.0+1.0, v/v) as the mobile phase. Densitometric analysis of L-dopa was carried out in the absorbance mode at 280 nm. The relationship between the concentration of L-dopa and corresponding peak areas was found to be linear in the range of 100 to 1200 ng/spot. The method was validated for precision (inter and intraday), repeatability, and accuracy. Mean recovery was 100.30%. The relative standard deviation (RSD) values of the precision were found to be in the range 0.64-1.52%. In conclusion, the proposed TLC method was found to be precise, specific and accurate and can be used for identification and quantitative determination of L-dopa in herbal extract and its formulations.     

HPTLC analysis of Withaferine A from an herbal extract and polyherbal formulations

Withania somnifera has been used in Ayurvedic medicine for treatment of depression and inflammation, and as an aphrodisiac. It contains many phytochemicals such as Withaferine A, withanine, anahygrine, tropine, and withanolides. Of these, withaferine A is considered to be the most active compound. Withaferine A was estimated in herbal extract and polyherbal formulations by high performance thin layer chromatography (HPTLC). As there is no official HPTLC protocol for quantitation of the above phytochemicals, an attempt was made to quantify withaferine A in herbal extract and polyherbal formulations produced from Withania somnifera. Precoated silica gel G (aluminium backed) plates were used as stationary phase and toluene:ethyl acetate: formic acid (50 : 15 : 5) was used as mobile phase. Detection and quantification were performed by densitometry at λ 213 nm. The linear range was 1 μg to 3 μg. This HPTLC method was found to be reproducible, accurate, and precise.     

Separation of Complex Fructo-Oligosaccharides (FOS) and Inulin Mixtures by HPTLC–AMD

JPC – Journal of Planar Chromatography – Modern TLC - A first attempt at the separation of fructo-oligosaccharides (FOS) and inulin mixtures is presented. Preliminary results obtained...     

Factors Affecting the Separation of Phthalate Esters,and their Analysis,by HPTLC

JPC – Journal of Planar Chromatography – Modern TLC - The phthalate esters (PAE) are ubiquitous in the environment because of the widespread use of plastic products. Reports of their...     

A validated HPTLC method for determination of trans-caryophyllene from polyherbal formulations

Formulations of traditional medicines are usually made up of a complex mixture of herbs. However, effective quality control methods in order to select materials of the right quality are lacking. 'Amukkara choornam' is a polyherbal Siddha formulation used for gastritis, spleen enlargement, leucorrhoea, hiccups, anaemia, tuberculosis and kappa diseases. Trans-caryophyllene is an important constituent present in the ingredients of this formulation. In a literature survey, it was found that there is no such method for the quantification of trans-caryophyllene except gas chromatography or gas chromatography-mass spectroscopy (GC-MS). So, a high performance thin layer chromatography (HPTLC) method was developed and validated for the quantification of trans-caryophyllene in amukkara choornam. Pre-coated silica gel 60F-254 plates (10 × 10 cm2) were used for the analysis. The solvent system consisted of toluene-ethyl acetatate (9 : 3, v/v), and trans-caryophyllene was detected at 260 nm. The developed method was validated for linearity (R2 = 0.9996 ± 0.0034), limit of detection (LOD) (0.101 ng), limit of quantification (LOQ) (0.639 ng), accuracy (% recovery = 97.19 ± 1.204), and precision (CV < 5%, for both intra-day and inter-day precisions). The levels of trans-caryophyllene were found to be 3.5-4.10 μg per gram of herbal products.     

Investigation of the Separation of Higher Fatty Acid Methyl Esters by Reversed-Phase HPTLC

JPC – Journal of Planar Chromatography – Modern TLC - Separations of eight methyl esters of higher fatty acids on RP-18 stationary phase with methanol—water and...     

HPTLC and GC-MS for Separation and Identification of Eugenol in Plants

JPC – Journal of Planar Chromatography – Modern TLC - Samples of clove, nutmeg, and cinnamon have been extracted by maceration with ethanol for 24 h and with aqueous ethanol 48 h....     

HPTLC method for the simultaneous determination of amlodipine and benazepril in their formulations

A new, simple, precise, rapid, and selective high-performance thin-layer chromatographic (HPTLC) method is developed for the simultaneous analysis of amlodipine and benazepril in pharmaceutical formulations. The method uses zolpidem as an internal standard (IS). The stationary phase used is silica gel 60 F254 prewashed with methanol. The mobile phase consists of an ethyl acetate-methanol-ammonia solution (8.5:2.0:1.0, v/v/v). Detection and quantitation are performed densitometrically at lambda = 254 nm. The Rf values of amlodipine, benazepril, and zolpidem (IS) are 0.58, 0.50, and 0.78, respectively. The limits of detection of amlodipine and benazepril are 0.02 and 0.2 microg; linearity ranges are 0.1-0.8 and 0.2-2.0 microg; and the percentage recoveries are 99.79% and 100.25%, respectively.     

Radiation sterilization of antibiotic liposome formulations: A case study

New liposome formulations for antimycobacterial purpose are under development in Portugal. The drug must be submitted to a sterilization process. In order to find out if gamma radiation could be applied, microbiological and chemical studies were developed based on ISO standards. The bioburden was determined, the main critical points of line production were detected and the sterilization dose was determined based on a chart control for bioburden. A preliminary maximum acceptable dose for product was found out based on the main functional parameters.