Desloratadine Assay with HPLC – AppNote

Alternate L1 Column used for HPLC Method of Desloratadine This Desloratadine Assay is easily performed and the five injection overlay below demonstrates Run to Run consistency and Precision. The Peak Efficiency is very good and Peak Tailing guidelines are easily met with RSD values below 0.3%. This demonstrates a good alternate Column for your Desloratadine […]

Read More

Diazepam Tablet Analyzed with HPLC – AppNote

Excellent Peak Shape and Precision for a Benzodiazepine Compound Valium® This Isocratic Method shows how using 0.1% Trifluoroacetic Acid (TFA) in the Mobile Phase can produce a Peak with excellent Efficiency and Symmetry. In the USP Assay Method, System Suitability requires that a tailing factor of not more than 2.0 be obtained for the API, […]

Read More

Digoxin Analyzed with HPLC – AppNote

Forced Degradation Method Digoxin had several Sugar Residues that can be hydrolyzed in acidic conditions. In this Forced Degradation Method, six degradants are observed. Some of these Peaks are likely the various hydrolyzed forms, including the Aglycone Digoxigenin. The Method is capable of Separating a wide variety of Degradants. Figure A shows the Chromatogram of […]

Read More

Dipyridamole Analyzed with HPLC – AppNote

Several Tertiary Amines on a Molecule that is Easily Retained This Method for the Analysis of Dipyridamole USP Tablet Formulation is easy to do. Note the excellent Resolution from capsule excipients, along with the excellent Peak shape for this complex, difficult molecule.   Peaks: 1. Dipyridamole 2. Tablet Excipients Method Conditions Column: Cogent Bidentate C18™, 4μm, […]

Read More

DMAP, 4-Dimethylaminopyridine Analyzed with HPLC – AppNote

Analyzing the Catalyst, DMAP, 4-Dimethylaminopyridine with HPLC This AppNote shows a rapid, reliable, Isocratic Reversed Phase, HPLC Method that was developed for the Analysis of an important Catalyst for many applications and industries: 4-Dimethylaminopyridine (DMAP). Peak: DMAP Method Conditions Column: Cogent Diamond Hydride™, 4μm, 100Å Catalog No.: 70000-7.5P Dimensions: 4.6 x 75mm Mobile Phase: —90:10 Solvent A / […]

Read More

Docusate Sodium Analyzed with HPLC – AppNote

A Simple Gradient with Good Separation    The official USP assay method for Docusate Sodium tablets calls for a Mobile Phase of 50% 7mM Ammonium Acetate / 50% Acetonitrile at 40°C. However, retention for the API and the System Suitability compound Methyl Paraben were found to be low using these conditions. This Method not only […]

Read More

Doxycycline Analyzed with HPLC – AppNote

Forced Degradation Method Using Shape Selectivity Doxycycline is known to epimerize at the C4 and C6 positions in acid conditions. Epimers can be difficult to separate in Reversed Phase due to subtle differences in hydrophobicity. However, this Method differentiates based on shape as well as hydrophobicity and is therefore well suited to this Isomer separation. […]

Read More

Doxycycline and Methacycline Analyzed with HPLC – AppNote

Simple Isocratic Method for API and Main Impurity Formulations of Doxycycline may contain a Methacycline Impurity.  As such, it is crucial for analytical methods to be able to separate these two peaks. Using this simple isocratic Method, the baseline resolution is obtained for this pair. Peaks: 1. Methacycline 2. Doxycycline * Impurities in doxycycline standard […]

Read More

Dyclonine HCL Analyzed with HPLC – AppNote

A Reproducible Method for Detection of Dyclonine Hydrochloride A rapid, sensitive, and reproducible Method has been developed for detection of Dyclonine HCL. The data below, (overlay of 20 chromatograms ) illustrates how the compound can be adequately Retained and detected using HPLC, with both excellent Peak Shape and run-to-run precision. Using a simple Gradient in […]

Read More

EDTA Analysis with HPLC – AppNote

EDTA does not have a significant Chromophore, so to achieve UV Detection, in the Method shown below we used a pre-Column reaction of a Solution of Ferric Chloride with the Sample. The resulting EDTA/Fe3+ has significant UV Absorbance making this a very Sensitive Method. Ethylenediaminetetraacetic acid is extremely difficult to analyze by itself however in […]

Read More

EDTA Analyzed with HPLC – AppNote

Very Sensitive Method for Measuring Ethylenediaminetetraacetic Acid EDTA does not have a significant Chromophore, so to achieve UV Detection, this Method uses a Pre-Column reaction of a solution of Ferric Chloride with the sample. The resulting EDTA / Fe3+ has significant UV Absorbance making this a very sensitive Method. With this Method, Peak Shapes and […]

Read More

Epigallocatechin Gallate Analyzed with HPLC – AppNote

A Reliable Method for a EGCG Analysis This Epigallocatechin Gallate (EGCG) Assay produces Run to Run consistency and Precision with Retention Time RSD values of 0.02%.  This is a sensitive HPLC-UV Method that may be used for quantification of EGCG in food and beverage formulations. Peak: Epigallocatechin Gallate  Method Conditions: Column: Cogent Zx Similars C18, […]

Read More

Etodolac Tablet Analyzed with HPLC – AppNote

An Assay Method for Etodolac Tablets The USP Assay Method for  Etodolac tablets uses a Phosphoric Acid based Mobile Phase which is not LCMS compatible. The Method in this Application Note is more versatile since it can be used for HPLC or LCMS. The Gradient can be adjusted if lower Retention is required. Data from […]

Read More

Fenofibric Acid Capsule Analyzed with HPLC – AppNote

Simple Isocratic LCMS Compatible Assay Method The USP Assay Method for Fenofibric Acid uses a Phosphate buffer which is incompatible with MS detection. In this isocratic Method, only Formic Acid is needed in the Mobile Phase. The Peak Efficiency and Symmetry are excellent and the run-to-run precision is reliable and robust, as the 10 Chromatograms […]

Read More

Fexofenadine Analyzed with HPLC – AppNote

Simple Isocratic Assay Method without Amine Additives Fexofenadine, antihistamine, has a number of aromatic moieties and the tertiary amine in its chemical structure that can cause Peak tailing issues when using most L11 Columns for Analysis. The USP Assay Monograph for Fexofenadine Tablets uses Triethylamine to reduce tailing. With this Method, Trifluoroacetic Acid is used […]

Read More

Fioricet Analyzed with HPLC – AppNote

Gradient Separation of Acetaminophen, Caffeine, and Butalbital In this Method, a simple Reversed Phase gradient is used to separate the three components of a Fioricet tablet. Figure A shows the five-run overlay obtained from the gradient. Figure B shows a “zoomed in view” so that the Butalbital Peak can be seen clearly. Peaks: 1. Acetaminophen […]

Read More

Fluorouracil Assay Analyzed with HPLC – AppNote

A Reliable Method for a Chemotherapeutic Drug This Fluorouracil Assay is easily performed and demonstrates Run to Run consistency and Precision with Retention Time RSD values below 0.1%. This Method shows reliability for analysis of this Pyrimidine Analog that is an anti-neoplastic anti-metabolite. Peak: Fluorouracil Method Conditions: Column: Cogent RP C18™, 5um, 100Å Catalog No.: […]

Read More

Fluphenazine HCl USP Tablet Assay with HPLC – AppNote

Alternate L7 Column used for the USP Assay Method of Fluphenazine HCl Tablets This USP Fluphenazine HCl Tablet Assay is easily performed and the five injection overlay below demonstrates Run to Run consistency and Precision. The Peak Efficiency is very good and Peak Tailing guidelines are easily met with RSD values of 0.2%. This demonstrates […]

Read More

Forced Degradation of Atorvastatin by LCMS – AppNote

Separation of API from its Lactone Degradation Product Atorvastatin is separated from its main Degradation product in this Method with a simple linear Reversed Phase Gradient. With the use of LCMS, the identity of the Degradant can be confirmed from its m/z value. The Degradation is an intramolecular Fischer esterification, which is catalyzed under Acidic […]

Read More

Formoterol Fumarate Analyzed with HPLC – AppNote

Forced Degradation Methods  Forced degradation studies are useful for developing Stability Indicating Methods of Pharmaceuticals. In this Application Note Separation is obtained between the API and a Degradant formed under two different, strong acidic conditions. The non-degraded Sample produced a sharp, Symmetrical Peak for the API shown in Figure A. In Figure B, strong acid […]

Read More

Furazolidone Analyzed with HPLC – AppNote

Improved Specificity Compared to USP Assay Method The USP Assay Method for Furazolidone is performed by UV Spectrophotometry. This HPLC Method provides more Robustness and Specificity for the analysis. Separation of Furazolidone from the structurally similar compound Nitrofurantoin is shown in the figure. Nitrofurantoin can be used as an internal standard to obtain more robust […]

Read More

Furazolidone Analyzed with HPLC – AppNote

API and Related Compounds Separation Furazolidone was Separated from related compounds in a commercially available pharmaceutical preparation. Excellent Peak shape and Selectivity from the related compounds was achieved with this Robust Method making it a great choice for QC applications even when using aggressive Mobile Phases that include acids. Molecular weight of Furazolidone is 225.16. […]

Read More

Furosemide Analyzed with HPLC – AppNote

Furosemide & Related Compound with Improved Peak Shapes Furosemide and its related compound can be a difficult molecule to chromatograph with conventional L1 (C18) Columns due to Silanol activity. With this Method, the Peak shape of Furosemide and its related Compound A is excellent and baseline Resolution is achieved between this specified impurity and Furosemide. […]

Read More

Gemcitabine Assay Analyzed with HPLC – AppNote

A Reliable Method for a Chemotherapeutic Drug This Gemcitabine Assay is easily performed and demonstrates Run to Run consistency and Precision with Retention Time RSD values below 0.4%. This Method shows consistency and reliability for analysis of this Nucleoside Chemotherapeutic. Peak: Gemcitabine Method Conditions: Column: Cogent RP C8™, 5um, 150Å Catalog No.: 68508-25P Dimensions: 4.6mm […]

Read More

Gentian Violet Analyzed with HPLC – AppNote

Separation of Related Compounds Gentian Violet degrades in solution, forming complex set of Degradation products. This Method can easily separate out the various compounds formed in Solution. The figure below shows a USP Standard of Gentian Violet after stressing it in solution thus creating Degradation products. With excellent Selectivity well as great Peak shape this […]

Read More

Glimepiride Tablet Analyzed with HPLC – AppNote

Isocratic Assay Method for a Diabetes Drug In this study, an Isocratic, HPLC Method for Glimepiride Analysis in a tablet formulation is presented. The USP Assay Method for this drug calls for a Phosphate Buffer and is therefore not LCMS compatible. This Method uses Formic Acid instead and produces a Symmetrical, well-Retained Peak. Therefore the […]

Read More

Glipizide Analyzed with HPLC – AppNote

Separation of API from Acid Degradation Products This Method illustrates the capabilities to separate several Glipizide Degradants that are formed under acidic conditions. Good separation is obtained as well as Sharp, Symmetric Peak shapes for each compound. The Retention times show good repeatability as well, as demonstrated in the Figure overlays. Also, the Mobile Phase […]

Read More

Glyburide and Metformin Analyzed with HPLC – AppNote

Separation of “Highly Polar” and “Non-Polar” Compounds in one Isocratic run In this Method, the polar compound, Metformin, and the nonpolar compound Glyburide, can be retained on the same Stationary Phase (see A & B). Depending on the Mobile Phase composition either Metformin or Glyburide can be retained longer. Method Conditions Column: Cogent Bidentate C18™, […]

Read More

Glycosidic Flavonoids Analyzed with HPLC – AppNote

Separation of Diosmin, Eriocitrin, and Naringin In this method, three Glycosidic flavonoid standards are separated with good resolution. The Cogent Bidentate C18 2.o™ Column produces high efficiency peaks with reproducible retention (see figure overlay). Separation is also observed for a small impurity peak, eluting between peaks 1 and 2. This separation of standards could be […]

Read More

Guanfacine HCL and Degradants Analyzed with HPLC – AppNote

USP Method with an SDS Resistant Column The US Pharmacopeia (USP) lists several known degradation products for Guanfacine. The Figure below shows a Separation of a degraded Guanfacine Drug Substance. This Method produces very Efficient results but what is important to note is that the Column used is extremely stable under the very aggressive Mobile […]

Read More

Hesperidin Analyzed with HPLC – AppNote

LC-MS compatible method This method for analysis of Hesperidin produces an excellent analyte peak and shows separation from what appears to be two impurity peaks. The gradient method is LC-MS compatible and can be applied to many types of Hesperidin-containing samples such as citrus fruit extracts. The overlay of five runs shown in the figure […]

Read More

Hormone Replacement Capsule Analysis with HPLC – AppNote

Separation of Estriol, Estradiol, & Progesterone This gradient method features a separation of the three components of a hormone replacement formulation. Figure A shows a five run overlay of the formulation extract injections. Figure B shows a zoomed-in view so that the Estriol and Estradiol Peaks, which are present in much lower concentration than Progesterone, can […]

Read More

Hormone Replacement HPLC Methods – Extended AppNote

Ethinylestradiol, Norethisterone Acetate, Estriol, Estradiol, Progesterone, Separation in Hormone Replacement Formulations. Often, these formulations have multiple active ingredients present, therefore HPLC is an appropriate technique in obtaining the necessary specificity for a Quantitative Assay. This Method can retain the Hormones by conventional Reversed Phase HPLC and can also differentiate among the compounds by shape. The […]

Read More

Hormone Replacement Tablet Analyzed with HPLC – AppNote

Isocratic Separation of Ethinylestradiol and Norethisterone Acetate In this simple HPLC Method, two hormones from a tablet extract are separated. Both analytes are adequately retained while keeping the run time to 10 minutes. The USP Monograph Method for Assay of the two compounds is lengthy and complex, while this Method is rapid and easy to […]

Read More

Hydrocodone with Acetaminophen Analyzed with HPLC – AppNote

Simple, Robust Assay Method Hydrocodone can yield poor Peak shapes in many conventional Reversed Phase C18 Methods due to its tertiary amine group. The USP Assay Method for Hydrocodone in combination with Acetaminophen uses Triethylamine as a Mobile Phase additive to improve the Peak shape. In this Method however, only Trifluoroacetic Acid is needed in […]

Read More

Hydrocortisone USP Assay with HPLC – AppNote

Alternate L1 Column used for the USP Assay Method of Hydrocortisone This USP Hydrocortisone Assay is easily performed and the five injection overlay below demonstrates Run to Run consistency and Precision. The Peak Efficiency is very good and Peak Tailing guidelines are easily met with RSD values of 0.5%. This demonstrates a good alternate Column […]

Read More

Hydrophobic Compounds Analyzed With HPLC – AppNote

Shorter Analysis Time For separations requiring a less hydrophobic Stationary Phase, Cogent C8 can be used successfully as demonstrated in the Chromatograms. The Retention on the C8 Column is lower when compared with a C18 Column under the same Mobile Phase conditions, but since the Efficiency is excellent the separation goals can be achieved in […]

Read More

Ibuprofen Assay Method Reproducibility with HPLC – AppNote

Extremely Precise, Assay Method This Assay Method for a common Ibuprofen formulation demonstrates Reproducibility and Robustness as the Figure below shows an overlay of four Chromatograms with different Columns lots (%RSD < 1). An important aspect of Column Selection for a Method is that the Retention behavior is consistent across numerous manufacturing batches. This is […]

Read More

Ifosfamide Assay Analyzed with HPLC – AppNote

A Reliable Method for an Antineoplastic Chemotherapeutic Drug This Ifosfamide Assay is easily performed and demonstrates Run to Run consistency and Precision with Retention Time RSD values below 0.8%. This Method shows reliability for analysis of this Pyrimidine analog that is an antineoplastic anti-metabolite. Peak: Ifosfamide Method Conditions: Column: Cogent RP C18™, 5um, 100Å Catalog […]

Read More

Indomethacin Capsule Analyzed with HPLC – AppNote

Simple Assay Method  This method for analysis of Indomethacin capsules is easy to perform and uses an LC-MS compatible Mobile Phase. The API peak that was obtained shows excellent efficiency and the data is very reproducible, as illustrated by the overlay of five runs shown in the figure. Peak: Indomethacin Method Conditions Column: Cogent Bidentate […]

Read More

Ketorolac Separation with LCMS – AppNote

Analgesic agent There is a need for analysis of the Active Pharmaceutical Ingredient (API) in Ketorolac Tablet formulations in order to evaluate two different extraction protocols. The use of Ethanol as the extraction solvent was explored initially but DI Water was observed to produce superior extraction efficiency. The chromatograms show how the compound can be […]

Read More

Lamotrigine Analyzed with HPLC – AppNote

USP Assay Method for a Very Polar Compound The USP Assay Method for Lamotrigine uses a relatively low pH of 2.0. These conditions may promote hydrolysis of the bonded phase in many L1 Columns, but the unique chemistry of the Cogent Bidentate C18 Column (L1) is very rugged and shows no loss of Retention for […]

Read More

Lansoprazole Capsule Analyzed with HPLC – AppNote

Separation from matrix peaks Lansoprazole is separated from several Matrix Components in this simple assay method. The Mobile Phase is LC-MS compatible so the method could be applied to more complex samples such as plasma. Five runs are shown in the figure to illustrate the repeatability of the data. Peak:Lansoprazole Method Conditions Column: Cogent Bidentate […]

Read More

Levothyroxine Analysis – AppNote

Superior Resolution, Reproducibility, & Peak Shapes Compared to USP Method The USP assay method for Levothyroxine requires that a resolution of not less than 5.0 must be demonstrated between Levothyroxine and related compound Liothyronine. A chromatogram obtained from following the USP method using a Type-B Silica based L10 Column is shown in Figure B. The […]

Read More

Limonin in Orange Juice Analyzed by LC-MS – AppNote

Separation from Matrix Peaks with Reproducible Results Analysis of Limonin in Spiked Orange Juice was performed using a simple isocratic method with MS detection. Analysis at 471.2 m/z allowed for detection of only the Limonin peak without interference of the juice matrix. When the Filtered, Unspiked Orange Juice was injected, a small peak for Limonin […]

Read More

Limonin in Orange Juice Analyzed with HPLC – AppNote

Reproducible Separation from Sample Matrix Peaks An Orange Juice Sample was spiked at the level of 250 ppm of Limonin and filtered (MicroSolv Tech Corp. 0.45μm Nylon Syringe Filter)  before injection. Several Peaks from to the Juice Sample Matrix were separated (peaks1–5), the Limonin peak was well separated from the other Peaks and was easy […]

Read More

Limonin Repeatability in HPLC Analyses – AppNote

Separating Limonin from Matrix Peaks When Limonin determination is done with HPLC, the main drawback of some Methods is poor Reproducibility of the results. Using the Method in this AppNote, a simple Isocratic Method, helped to achieve acceptable Repeatability of the results. The %RSD for Peak Areas was 1.64 for 10 consecutive injections. Peak 1 […]

Read More

Meloxicam Tablet Analyzed with HPLC – AppNote

Rapid, Reliable Isocratic Method for this API The USP Assay Monograph Method for Meloxicam uses a phosphate based Mobile Phase. In this application note, a 0.1% Formic Acid additive is chosen in lieu of phosphates in order to be LCMS compatible. The System Suitability requirement is not more than 2.0 for Tailing factor. Highly Symmetrical […]

Read More

Meprobamate Analysis by LCMS – AppNote

Rapid & Simple Analysis of Meprobamate. One Step Sample Preparation with Plasma or Urine Several methods have been reported in the literature for the quantification of Meprobamate in biological samples (plasma, urine, hair etc) for patient monitoring and other tests. Most of these methods present the drawbacks of long analysis time and complex sample pre-treatment […]

Read More