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Bos TS, Pirok BWJ, Karlson L, Schantz S, Dahlseid TA, Stoll DR, Somsen GW. Fingerprinting of hydroxy propyl methyl cellulose by comprehensive two-dimensional liquid chromatography-mass spectrometry of monomers resulting from acid hydrolysis. J Chromatogr A 2024; 1722:464874. [PMID: 38598893 DOI: 10.1016/j.chroma.2024.464874] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2023] [Revised: 03/19/2024] [Accepted: 04/03/2024] [Indexed: 04/12/2024]
Abstract
Hydroxypropyl methyl cellulose (HPMC) is a type of cellulose derivative with properties that render it useful in e.g. food, cosmetics, and pharmaceutical industry. The substitution degree and composition of the β-glucose subunits of HPMC affect its physical and functional properties, but HPMC characterization is challenging due to its high structural heterogeneity, including many isomers. In this study, comprehensive two-dimensional liquid chromatography-mass spectrometry was used to examine substituted glucose monomers originating from complete acid hydrolysis of HPMC. Resolution between the different monomers was achieved using a C18 and cyano column in the first and second LC dimension, respectively. The data analysis process was structured to obtain fingerprints of the monomers of interest. The results revealed that isomers of the respective monomers could be selectively separated based on the position of substituents. The examination of two industrial HPMC products revealed differences in overall monomer composition. While both products contained monomers with a similar degree of substitution, they exhibited distinct regioselectivity.
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Affiliation(s)
- Tijmen S Bos
- Division of Bioanalytical Chemistry, Amsterdam Institute of Molecular and Life Sciences, Vrije Universiteit Amsterdam, De Boelelaan 1085, HV, Amsterdam 1081, the Netherlands; Centre for Analytical Sciences Amsterdam (CASA), the Netherlands.
| | - Bob W J Pirok
- Van 't Hoff Institute for Molecular Science (HIMS), University of Amsterdam, Science Park 904, XH, Amsterdam 1098, the Netherlands; Centre for Analytical Sciences Amsterdam (CASA), the Netherlands
| | - Leif Karlson
- Nouryon Chemicals, Zutphenseweg 10, AJ, Deventer 7418, the Netherlands
| | - Staffan Schantz
- Oral Product Development, Pharmaceutical Technology & Development, Operations, AstraZeneca, SE-431 83, Mölndal, Sweden
| | - Tina A Dahlseid
- Department of Chemistry, Gustavus Adolphus College, Saint Peter, Minnesota, 56082 United States
| | - Dwight R Stoll
- Department of Chemistry, Gustavus Adolphus College, Saint Peter, Minnesota, 56082 United States
| | - Govert W Somsen
- Division of Bioanalytical Chemistry, Amsterdam Institute of Molecular and Life Sciences, Vrije Universiteit Amsterdam, De Boelelaan 1085, HV, Amsterdam 1081, the Netherlands; Centre for Analytical Sciences Amsterdam (CASA), the Netherlands
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2
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Tang S, Pederson Z, Meany EL, Yen CW, Swansiger AK, Prell JS, Chen B, Grosskopf AK, Eckman N, Jiang G, Baillet J, Pellett JD, Appel EA. Label-Free Composition Analysis of Supramolecular Polymer-Nanoparticle Hydrogels by Reversed-Phase Liquid Chromatography Coupled with a Charged Aerosol Detector. Anal Chem 2024; 96:5860-5868. [PMID: 38567987 DOI: 10.1021/acs.analchem.3c05747] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/16/2024]
Abstract
Supramolecular hydrogels formed through polymer-nanoparticle interactions are promising biocompatible materials for translational medicines. This class of hydrogels exhibits shear-thinning behavior and rapid recovery of mechanical properties, providing desirable attributes for formulating sprayable and injectable therapeutics. Characterization of hydrogel composition and loading of encapsulated drugs is critical to achieving the desired rheological behavior as well as tunable in vitro and in vivo payload release kinetics. However, quantitation of hydrogel composition is challenging due to material complexity, heterogeneity, high molecular weight, and the lack of chromophores. Here, we present a label-free approach to simultaneously determine hydrogel polymeric components and encapsulated payloads by coupling a reversed phase liquid chromatographic method with a charged aerosol detector (RPLC-CAD). The hydrogel studied consists of modified hydroxypropylmethylcellulose, self-assembled PEG-b-PLA nanoparticles, and a therapeutic compound, bimatoprost. The three components were resolved and quantitated using the RPLC-CAD method with a C4 stationary phase. The method demonstrated robust performance, applicability to alternative cargos (i.e., proteins) and was suitable for composition analysis as well as for evaluating in vitro release of cargos from the hydrogel. Moreover, this method can be used to monitor polymer degradation and material stability, which can be further elucidated by coupling the RPLC method with (1) a multi-angle light scattering detector (RPLC-MALS) or (2) high resolution mass spectrometry (RPLC-MS) and a Fourier-transform based deconvolution algorithm. We envision that this analytical strategy could be generalized to characterize critical quality attributes of other classes of supramolecular hydrogels, establish structure-property relationships, and provide rational design guidance in hydrogel drug product development.
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Affiliation(s)
- Shijia Tang
- Synthetic Molecule Pharmaceutical Sciences, Genentech, Inc., South San Francisco, California 94080, United States
| | - Zachary Pederson
- Synthetic Molecule Pharmaceutical Sciences, Genentech, Inc., South San Francisco, California 94080, United States
| | - Emily L Meany
- Department of Bioengineering, Stanford University, Stanford, California 94305, United States
| | - Chun-Wan Yen
- Synthetic Molecule Pharmaceutical Sciences, Genentech, Inc., South San Francisco, California 94080, United States
| | - Andrew K Swansiger
- Department of Chemistry and Biochemistry, University of Oregon, Eugene, Oregon 97403, United States
| | - James S Prell
- Department of Chemistry and Biochemistry, University of Oregon, Eugene, Oregon 97403, United States
| | - Bifan Chen
- Synthetic Molecule Pharmaceutical Sciences, Genentech, Inc., South San Francisco, California 94080, United States
| | - Abigail K Grosskopf
- Preclinical and Translational Pharmacokinetics and Pharmacodynamics, Genentech, Inc, South San Francisco, California 94080, United States
| | - Noah Eckman
- Department of Chemical Engineering, Stanford University, Stanford, California 94305, United States
| | - Grace Jiang
- Department of Bioengineering, Stanford University, Stanford, California 94305, United States
| | - Julie Baillet
- Department of Materials Science and Engineering, Stanford University, Stanford, California 94305, United States
| | - Jackson D Pellett
- Synthetic Molecule Pharmaceutical Sciences, Genentech, Inc., South San Francisco, California 94080, United States
| | - Eric A Appel
- Department of Materials Science and Engineering, Stanford University, Stanford, California 94305, United States
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3
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Botan MVG, da Silva JB, Bruschi ML. Development of nanostructured environmentally responsive system containing hydroxypropyl methylcellulose for nose-to-brain administration of meloxicam. Int J Biol Macromol 2024; 262:130015. [PMID: 38331066 DOI: 10.1016/j.ijbiomac.2024.130015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2023] [Revised: 01/23/2024] [Accepted: 02/05/2024] [Indexed: 02/10/2024]
Abstract
The intranasal administration of drugs using environmentally responsive formulations, employing a combination of hydroxypropyl methylcellulose (HPMC) and poloxamer 407 (P407), can result in release systems that may assist in the treatment of neurological diseases. Meloxicam, considered a potential adjuvant in the treatment of Alzheimer's disease, could be used in these platforms. The aim of this work was to develop a mucoadhesive, thermoresponsive, and nanostructured system containing HPMC for nose-to-brain administration of meloxicam. The initially selected systems were investigated for their rheological, mechanical, and micellar size characteristics. The systems were dilatant at 25 °C and pseudoplastic with a yield value at 37 °C, showing viscoelastic properties at both temperatures. The platform containing HPMC (0.1%, w/w) and P407 (17.5%, w/w) was selected and demonstrated good mucoadhesive properties, along with an appropriate in vitro release profile. HPMC could form a binary system with P407, displaying superior mucoadhesive and thermoresponsive properties for nose-to-brain meloxicam administration, indicating that the selected formulation is worthy of clinical studies.
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Affiliation(s)
- Maria Vitoria Gouveia Botan
- Laboratory of Research and Development of Drug Delivery Systems, Postgraduate Program in Pharmaceutical Sciences, Department of Pharmacy, State University of Maringa, Av. Colombo 5790, 87020-900 Maringa, Parana, Brazil
| | - Jéssica Bassi da Silva
- Laboratory of Research and Development of Drug Delivery Systems, Postgraduate Program in Pharmaceutical Sciences, Department of Pharmacy, State University of Maringa, Av. Colombo 5790, 87020-900 Maringa, Parana, Brazil
| | - Marcos Luciano Bruschi
- Laboratory of Research and Development of Drug Delivery Systems, Postgraduate Program in Pharmaceutical Sciences, Department of Pharmacy, State University of Maringa, Av. Colombo 5790, 87020-900 Maringa, Parana, Brazil.
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4
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Darade AR, Lapteva M, Ling V, Kalia YN. Polymeric micelles for cutaneous delivery of the hedgehog pathway inhibitor TAK-441: Formulation development and cutaneous biodistribution in porcine and human skin. Int J Pharm 2023; 644:123349. [PMID: 37633540 DOI: 10.1016/j.ijpharm.2023.123349] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2023] [Revised: 08/21/2023] [Accepted: 08/23/2023] [Indexed: 08/28/2023]
Abstract
TAK-441 is a potent inhibitor of the hedgehog pathway (IC50 4.4 nM) developed for the treatment of basal cell carcinoma that is active against the vismodegib-resistant Smoothened receptor D473H mutant. The objective of this study was to develop a micelle-based formulation of TAK-441 using D-α-Tocopherol polyethylene glycol 1000 succinate (TPGS) and to investigate its cutaneous delivery and biodistribution. The micelles were prepared using solvent evaporation and incorporation of TAK-441 in the TPGS micelles increased aqueous solubility ∼40-fold. The optimal formulation, a 3% HPMC hydrogel of TAK-441 loaded TPGS micelles, retained ∼92% of the initial TAK-441 content (2.5 mgTAK-441/g) after storage at 4 °C for 6 months. Finite dose experiments using human skin demonstrated that this formulation resulted in significantly greater cutaneous deposition of TAK-441 after 12 h than a non-micelle control formulation, (0.40 ± 0.11 µg/cm2 and 0.05 ± 0.02 µg/cm2, respectively) - no transdermal permeation was observed. The cutaneous biodistribution profile demonstrated that TAK-441 was predominantly delivered to the viable epidermis and upper dermis. Delivery from the HPMC hydrogel formulation resulted in TAK-441 epidermal concentrations that were several thousand-fold higher than the IC50, with almost negligible transdermal permeation, thereby decreasing the risk of systemic side effects in vivo.
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Affiliation(s)
- Aditya R Darade
- School of Pharmaceutical Sciences, University of Geneva, CMU, 1 rue Michel-Servet, 1211, Geneva 4, Switzerland; Institute of Pharmaceutical Sciences Western Switzerland, University of Geneva, Geneva, Switzerland
| | - Maria Lapteva
- School of Pharmaceutical Sciences, University of Geneva, CMU, 1 rue Michel-Servet, 1211, Geneva 4, Switzerland; Institute of Pharmaceutical Sciences Western Switzerland, University of Geneva, Geneva, Switzerland
| | - Vincent Ling
- Takeda Pharmaceuticals, Drug Delivery Technologies Search and Evaluation, 40 Landsdowne St, Cambridge MA 02139, United States
| | - Yogeshvar N Kalia
- School of Pharmaceutical Sciences, University of Geneva, CMU, 1 rue Michel-Servet, 1211, Geneva 4, Switzerland; Institute of Pharmaceutical Sciences Western Switzerland, University of Geneva, Geneva, Switzerland.
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Sriram A, Tangirala S, Atmakuri S, Hoque S, Modani S, Srivastava S, Mahajan S, Maji I, Kumar R, Khatri D, Madan J, Singh PK. Budding Multi-matrix Technology-a Retrospective Approach, Deep Insights, and Future Perspectives. AAPS PharmSciTech 2021; 22:264. [PMID: 34734325 DOI: 10.1208/s12249-021-02133-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Accepted: 08/30/2021] [Indexed: 11/30/2022] Open
Abstract
The human race is consistently striving for achieving good health and eliminate disease-causing factors. For the last few decades, scientists have been endeavoring to invent and innovate technologies that can substitute the conventional dosage forms and enable targeted and prolonged drug release at a particular site. The novel multi-matrix technology is a type of matrix formulation where the formulation is embraced to have a matrix system with multiple number of matrices. The MMX technology embraces with a combination of outer hydrophilic layer and amphiphilic/lipophilic core layer, within which drug is encapsulated followed by enteric coating for extended/targeted release at the required site. In comparison to conventional oral drug delivery systems and other drug delivery systems, multi-matrix (MMX) technology formulations afford many advantages. Additionally, it attributes for targeting strategy aimed at the colon and offers modified prolonged drug release. Thus, it has emerged rapidly as a potential alternative option in targeted oral drug delivery. However, the development of this MMX technology formulations is a exigent task and also has its own set of limitations. Due to its promising advantages and colon targeting strategy over the other colon targeted drug delivery systems, premier global companies are exploiting its potential. This article review deep insights into the formulation procedures, drug delivery mechanism, advantages, limitations, safety and efficacy studies of various marketed drug formulations of MMX technology including regulatory perspectives and future perspectives.
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6
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Analysis of the Heterogeneities of First and Second Order of Cellulose Derivatives: A Complex Challenge. POLYSACCHARIDES 2021. [DOI: 10.3390/polysaccharides2040051] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
The complexity of the substituent distribution in polysaccharide derivatives is discussed and defined. The challenges regarding analytical characterization that results from various interrelated categories of distributions, including molecular weight, chemical composition, and microstructure, are outlined. Due to these convoluted levels of complexity, results should always be interpreted with carefulness. Various analytical approaches which have been applied to starch and cellulose derivatives are recapped, including enzymatic, mass spectrometric, and chromatographic methods. The relation of heterogeneities of first and second order among and along the polysaccharide chains is addressed. Finally, examples of own analytical work on cellulose ethers are presented, including the MS analysis of methyl cellulose (MC) blends and fractionation studies of fully esterified MC, especially its 4-methoxybenzoates by gradient HPLC on normal phase. Preparative fractionation according to the degree of substitution (DS) allows follow-up analysis in order to get more detailed information on the substituent distribution in such sub-fractions.
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7
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Tundisi LL, Mostaço GB, Carricondo PC, Petri DFS. Hydroxypropyl methylcellulose: Physicochemical properties and ocular drug delivery formulations. Eur J Pharm Sci 2021; 159:105736. [PMID: 33516807 DOI: 10.1016/j.ejps.2021.105736] [Citation(s) in RCA: 43] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Revised: 12/14/2020] [Accepted: 01/23/2021] [Indexed: 02/06/2023]
Abstract
Hydroxypropyl methylcellulose (HPMC) is a cellulose ether widely used in drug formulations due to its biocompatibility, uncharged nature, solubility in water and thermoplastic behavior. Particularly for ocular and ophthalmic formulations, HPMC is applied as viscosity enhancer agent in eye drops, gelling agent in injections, and polymeric matrix in films, filaments and inserts. The different therapeutic approaches are necessary due to the complex anatomic structure of the eye. The natural ocular barriers and the low drug permeation into the circulatory system make the drug administration challenging. This review presents the eye anatomy and the usual local routes of drugs administration, which are facilitated by the physicochemical properties of HPMC. The relationship between chemical structure and physicochemical properties of HPMC is displayed. The different types of formulations (local application) including HPMC for ocular drug delivery are discussed with basis on recent literature reports and patents.
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Affiliation(s)
- L L Tundisi
- Faculty of Pharmaceutical Sciences, University of Campinas (UNICAMP), Campinas, SP, Brazil
| | - G B Mostaço
- Ophthalmology Department, Faculty of Medicine, University of São Paulo, São Paulo, Brazil
| | - P C Carricondo
- Ophthalmology Department, Faculty of Medicine, University of São Paulo, São Paulo, Brazil
| | - D F S Petri
- Fundamental Chemistry Department, Institute of Chemistry, University of São Paulo, Av. Prof. Lineu Prestes 748, 05508-000São Paulo, Brazil.
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Pirok BWJ, Gargano AFG, Schoenmakers PJ. Optimizing separations in online comprehensive two-dimensional liquid chromatography. J Sep Sci 2017; 41:68-98. [PMID: 29027363 PMCID: PMC5814945 DOI: 10.1002/jssc.201700863] [Citation(s) in RCA: 148] [Impact Index Per Article: 21.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2017] [Revised: 09/21/2017] [Accepted: 09/21/2017] [Indexed: 12/16/2022]
Abstract
Online comprehensive two-dimensional liquid chromatography has become an attractive option for the analysis of complex nonvolatile samples found in various fields (e.g. environmental studies, food, life, and polymer sciences). Two-dimensional liquid chromatography complements the highly popular hyphenated systems that combine liquid chromatography with mass spectrometry. Two-dimensional liquid chromatography is also applied to the analysis of samples that are not compatible with mass spectrometry (e.g. high-molecular-weight polymers), providing important information on the distribution of the sample components along chemical dimensions (molecular weight, charge, lipophilicity, stereochemistry, etc.). Also, in comparison with conventional one-dimensional liquid chromatography, two-dimensional liquid chromatography provides a greater separation power (peak capacity). Because of the additional selectivity and higher peak capacity, the combination of two-dimensional liquid chromatography with mass spectrometry allows for simpler mixtures of compounds to be introduced in the ion source at any given time, improving quantitative analysis by reducing matrix effects. In this review, we summarize the rationale and principles of two-dimensional liquid chromatography experiments, describe advantages and disadvantages of combining different selectivities and discuss strategies to improve the quality of two-dimensional liquid chromatography separations.
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Affiliation(s)
- Bob W J Pirok
- University of Amsterdam, Analytical-Chemistry Group, van 't Hoff Institute for Molecular Sciences, Amsterdam, The Netherlands.,TI-COAST, Science Park, Amsterdam, The Netherlands
| | - Andrea F G Gargano
- University of Amsterdam, Analytical-Chemistry Group, van 't Hoff Institute for Molecular Sciences, Amsterdam, The Netherlands.,Vrije Universiteit Amsterdam, Department of Bioanalytical Chemistry, Amsterdam Institute for Molecules, Medicines and Systems, Amsterdam, The Netherlands
| | - Peter J Schoenmakers
- University of Amsterdam, Analytical-Chemistry Group, van 't Hoff Institute for Molecular Sciences, Amsterdam, The Netherlands
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9
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Characterization of sodium carboxymethyl cellulose by comprehensive two-dimensional liquid chromatography. Carbohydr Polym 2015; 130:77-86. [DOI: 10.1016/j.carbpol.2015.04.011] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2015] [Revised: 03/29/2015] [Accepted: 04/13/2015] [Indexed: 11/21/2022]
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10
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von Schantz L, Schagerlöf H, Nordberg Karlsson E, Ohlin M. Characterization of the substitution pattern of cellulose derivatives using carbohydrate-binding modules. BMC Biotechnol 2014; 14:113. [PMID: 25540113 PMCID: PMC4302574 DOI: 10.1186/s12896-014-0113-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2014] [Accepted: 12/18/2014] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Derivatized celluloses, such as methylcellulose (MC) and hydroxypropyl methylcellulose (HPMC), are of pharmaceutical importance and extensively employed in tablet matrices. Each batch of derivatized cellulose is thoroughly characterized before utilized in tablet formulations as batch-to-batch differences can affect drug release. The substitution pattern of the derivatized cellulose polymers, i.e. the mode on which the substituent groups are dispersed along the cellulose backbone, can vary from batch-to-batch and is a factor that can influence drug release. RESULTS In the present study an analytical approach for the characterization of the substitution pattern of derivatized celluloses is presented, which is based on the use of carbohydrate-binding modules (CBMs) and affinity electrophoresis. CBM4-2 from Rhodothermus marinus xylanase 10A is capable of distinguishing between batches of derivatized cellulose with different substitution patterns. This is demonstrated by a higher migration retardation of the CBM in acrylamide gels containing batches of MC and HPMC with a more heterogeneous distribution pattern. CONCLUSIONS We conclude that CBMs have the potential to characterize the substitution pattern of cellulose derivatives and anticipate that with use of CBMs with a very selective recognition capacity it will be possible to more extensively characterize and standardize important carbohydrates used for instance in tablet formulation.
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Ghareeb HO, Radke W. Characterization of cellulose acetates according to DS and molar mass using two-dimensional chromatography. Carbohydr Polym 2013; 98:1430-7. [DOI: 10.1016/j.carbpol.2013.07.061] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2013] [Revised: 07/14/2013] [Accepted: 07/26/2013] [Indexed: 11/26/2022]
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12
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Fox CB, Sivananthan SJ, Mikasa TJ, Lin S, Parker SC. Charged aerosol detection to characterize components of dispersed-phase formulations. Adv Colloid Interface Sci 2013; 199-200:59-65. [PMID: 23855968 DOI: 10.1016/j.cis.2013.06.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2012] [Revised: 05/10/2013] [Accepted: 06/10/2013] [Indexed: 01/22/2023]
Abstract
Colloidal formulations based on biocompatible phospholipids, emulsifiers, and oils are employed in a wide range of applications including medicine, food, and cosmetics. However, characterization of these dispersed-phase components may be difficult to analyze by traditional HPLC with UV, visible, or fluorescence detection modalities due to lack of chromophores or fluorophores. Charged aerosol detection (CAD) is increasingly used for analysis of dispersed-phase components due to its broad applicability and high sensitivity for non-chromophore containing components found in many colloidal systems, such as lipid-based molecules. In this review, we summarize the recent applications of CAD reported in the literature as well as our own laboratory for the analysis of widely used components of dispersed-phase systems. In particular, we discuss the advantages and disadvantages of CAD compared to other HPLC detection methods, as well as the various sample preparation methods suitable for colloidal formulations prior to HPLC-CAD analysis.
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Akinosho H, Hawkins S, Wicker L. Hydroxypropyl methylcellulose substituent analysis and rheological properties. Carbohydr Polym 2013; 98:276-81. [DOI: 10.1016/j.carbpol.2013.05.081] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2012] [Revised: 05/24/2013] [Accepted: 05/28/2013] [Indexed: 11/28/2022]
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14
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Charged aerosol detection in pharmaceutical analysis. J Pharm Biomed Anal 2012; 69:50-63. [DOI: 10.1016/j.jpba.2012.03.019] [Citation(s) in RCA: 89] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2011] [Revised: 03/08/2012] [Accepted: 03/09/2012] [Indexed: 11/22/2022]
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15
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Resolving the chemical heterogeneity of natural organic matter: new insights from comprehensive two-dimensional liquid chromatography. J Chromatogr A 2012; 1249:138-46. [PMID: 22738816 DOI: 10.1016/j.chroma.2012.06.022] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2012] [Revised: 05/09/2012] [Accepted: 06/10/2012] [Indexed: 11/21/2022]
Abstract
For the purpose of resolving the chemical heterogeneity of natural organic matter (NOM), comprehensive two-dimensional liquid chromatography (LC×LC) was employed for the first time to map the hydrophobicity versus molecular weight (MW) distribution of two well-known complex organic mixtures: Suwannee River Fulvic Acids (SR-FA) and Pony Lake Fulvic Acids (PL-FA). Two methods have been developed using either a conventional reversed-phase (RP) silica column or a mixed-mode hydrophilic interaction column operating under aqueous RP mode in the first dimension, and a size-exclusion column in the second dimension. The LC×LC fractions were screened on-line by UV at 254 nm, molecular fluorescence at excitation/emission wavelengths (λ(Exc)/λ(Em)) of 240/450 nm, and by evaporative light scattering. The MW distributions of these two NOM samples were further characterized by number (Mn) and weight (Mw) average MW, and by polydispersity (Mw/Mn). Findings suggest that the combination of two independent separation mechanisms is promising in extend the range of NOM separation. For the cases where NOM separation was accomplished, smaller Mw group fractions seem to be related to a more hydrophobic nature. Regardless of the detection method, the complete range of MW distribution provided by both comprehensive LC×LC methods was found to be lower than those reported in the literature.
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16
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Recent developments in the detailed characterization of polymers by multidimensional chromatography. J Chromatogr A 2012; 1240:1-20. [DOI: 10.1016/j.chroma.2012.03.038] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2011] [Revised: 03/06/2012] [Accepted: 03/10/2012] [Indexed: 02/03/2023]
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17
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Šmigovec Ljubič T, Pahovnik D, Žigon M, Žagar E. Separation of poly(styrene-block-t-butyl methacrylate) copolymers by various liquid chromatography techniques. ScientificWorldJournal 2012; 2012:932609. [PMID: 22489207 PMCID: PMC3317551 DOI: 10.1100/2012/932609] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2011] [Accepted: 11/24/2011] [Indexed: 11/19/2022] Open
Abstract
The separation of a mixture of three poly(styrene-block-t-butyl methacrylate) copolymers (PS-b-PtBMA), consisting of polystyrene (PS) blocks of similar length and t-butyl methacrylate (PtBMA) blocks of different lengths, was performed using various chromatographic techniques, that is, a gradient liquid chromatography on reversed-phase (C18 and C8) and normal-phase columns, a liquid chromatography under critical conditions for polystyrene as well as a fully automated two-dimensional liquid chromatography that separates block copolymers by chemical composition in the first dimension and by molar mass in the second dimension. The results show that a partial separation of the mixture of PS-b-PtBMA copolymers can be achieved only by gradient liquid chromatography on reversed-phase columns. The coelution of the two block copolymers is ascribed to a much shorter PtBMA block length, compared to the PS block, as well as a small difference in the length of the PtBMA block in two of these copolymers, which was confirmed by SEC-MALS and NMR spectroscopy.
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Affiliation(s)
- Tina Šmigovec Ljubič
- Laboratory for Polymer Chemistry and Technology, National Institute of Chemistry, Hajdrihova 19, 1000 Ljubljana, Slovenia
| | - David Pahovnik
- Laboratory for Polymer Chemistry and Technology, National Institute of Chemistry, Hajdrihova 19, 1000 Ljubljana, Slovenia
| | - Majda Žigon
- Laboratory for Polymer Chemistry and Technology, National Institute of Chemistry, Hajdrihova 19, 1000 Ljubljana, Slovenia
- Center of Excellence for Polymer Materials and Technologies, Tehnološki Park 24, 1000 Ljubljana, Slovenia
- University College for Polymer Technology, Glavni trg 1, 2380 Slovenj Gradec, Slovenia
| | - Ema Žagar
- Laboratory for Polymer Chemistry and Technology, National Institute of Chemistry, Hajdrihova 19, 1000 Ljubljana, Slovenia
- EN-FIST Centre of Excellence, Dunajska 156, 1000, Ljubljana, Slovenia
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18
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Uliyanchenko E, van der Wal S, Schoenmakers PJ. Challenges in polymer analysis by liquid chromatography. Polym Chem 2012. [DOI: 10.1039/c2py20274c] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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