Characterization of Commercial PLGAs by NMR Spectroscopy

Characterization of Commercial PLGAs by NMR Spectroscopy | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Characterization of Commercial PLGAs by NMR Spectroscopy Jing Sun, Jennifer Walker, Moritz Beck-Broichsitter, Steve Schwendeman This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-325988/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 20 Aug, 2021 Read the published version in Drug Delivery and Translational Research → Version 1 posted 3 You are reading this latest preprint version Abstract Poly(lactic- co -glycolic acid) (PLGA) is among the most common of biodegradable polymers studied in various biomedical applications such as drug delivery and tissue engineering. To facilitate the understanding of the often overlooked PLGA microstructure on important factors affecting PLGA performance, we measured four key parameters of 17 commonly used commercial PLGA polymers (Resomer ®, Expansorb ®, Purasorb ®, Lactel ®, and Wako ® ) by NMR spectroscopy. 1 HNMR and 13 CNMR spectra were used to determine lactic to glycolic ratio (L/G ratio), polymer end-capping, glycolic blockiness ( Rc ), and average glycolic and lactic block lengths ( L G and L L ). In PLGAs with a labeled L/G ratio of 50/50 and acid end capping, the actual lactic content slightly decreased as molecular weight increased in both Resomer ® and Expansorb ®. Whether or not acid- or ester-, termination of these PLGAs was confirmed to be consistent with their brand labels. Moreover, in the ester end-capped 75/25 L/G ratio group, the blockiness value ( Rc ) of Resomer ® RG 756S ( Rc : 1.7) was highest in its group; whereas for the 50/50 acid end-capped group, Expansorb ® DLG 50-2A ( Rc : 1.9) displayed notably higher values than their counterparts. Resomer ® RG 502 ( L L : 2.6, L G : 2.5) and Expansorb ® DLG 50-2E ( L L : 2.5, L G : 2.6) showed the lowest block lengths, suggesting they may undergo a steadier hydrolytic process compared to random, heterogeneously distributed PLGA. Drug Discovery, Design, & Development Drug Delivery Biomedical Engineering PLGA blockiness block length degradation NMR spectroscopy. Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Full Text Due to technical limitations, full-text HTML conversion of this manuscript could not be completed. However, the manuscript can be downloaded and accessed as a PDF. Supplementary Files GraphicalAbstract.jpg SupportInformationJS07272020spsf.pdf Cite Share Download PDF Status: Published Journal Publication published 20 Aug, 2021 Read the published version in Drug Delivery and Translational Research → Version 1 posted Reviews received at journal 27 Mar, 2021 Reviewers invited by journal 26 Mar, 2021 First submitted to journal 12 Mar, 2021 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-325988","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":18814507,"identity":"37aa5fef-f212-469c-ae3f-8897b1a86365","order_by":0,"name":"Jing Sun","email":"","orcid":"","institution":"University of Michigan","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Jing","middleName":"","lastName":"Sun","suffix":""},{"id":18814508,"identity":"437f4905-a9f2-4654-8a20-0c157f2a930e","order_by":1,"name":"Jennifer Walker","email":"","orcid":"","institution":"University of Michigan","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Jennifer","middleName":"","lastName":"Walker","suffix":""},{"id":18814509,"identity":"3b047c36-0c05-41a7-9aab-6ed731f09342","order_by":2,"name":"Moritz Beck-Broichsitter","email":"","orcid":"","institution":"Merck KGaA","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Moritz","middleName":"","lastName":"Beck-Broichsitter","suffix":""},{"id":18814510,"identity":"2ffbc274-5283-48cc-896c-ab29feed5170","order_by":3,"name":"Steve Schwendeman","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA0klEQVRIiWNgGAWjYHACNhDB2MDeAKQMLEjRwnMApEWCFC0SCSCaCC3y/YefPeapuCPbL/n86oYfBRIM/O3dCXi1GNxIMzfmOfPMeObsnLKbPUCHSZw5uwG/FgkeNunctsOJG27npN3gAWoxkMjFr0W+/wxQy7/Diftvnkm7+YcYLQwHcoBaGoC2SLAfu02ULUC/mEn/OXbYeMaZHLbbMkB3EvQLKMQkZ9Qclu1vP/7s5ps/NnL87b0EHIYAPAZgkljlIMD+gBTVo2AUjIJRMIIAAEsnSZYPZ3TTAAAAAElFTkSuQmCC","orcid":"","institution":"University of Michigan","correspondingAuthor":true,"submittingAuthor":false,"prefix":"","firstName":"Steve","middleName":"","lastName":"Schwendeman","suffix":""}],"badges":[],"createdAt":"2021-03-13 19:17:43","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-325988/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-325988/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1007/s13346-021-01023-3","type":"published","date":"2021-08-20T15:03:18+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":7492006,"identity":"f272b66e-3aca-41c1-b2bf-eafc0d94f167","added_by":"auto","created_at":"2021-03-30 17:27:07","extension":"jpg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":48711,"visible":true,"origin":"","legend":"Characteristic proton peaks of PLGA polymers in 1HNMR spectra (CDCl3, 500 MHz). A, B and C represent the spectra of three PLGAs with L/G ratio of 50/50, 75/25 and 100/0, respectively (Expansorb® DLG 50-5A, Expansorb® DLG 75-2A and Expansorb® DLG 100-2A). Labels corresponding to the peaks of (i) and (iii) are the protons of methine and side methyl groups in lactic mer units, respectively; (ii) protons of methylene in glycolic mers.","description":"","filename":"fig1.jpg","url":"https://assets-eu.researchsquare.com/files/rs-325988/v1/94dba62a4e15545da712c35a.jpg"},{"id":7493028,"identity":"4ec5d847-88e1-433a-aae7-68ae1a825210","added_by":"auto","created_at":"2021-03-30 17:36:07","extension":"jpg","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":96362,"visible":true,"origin":"","legend":"Calculated molar lactic acid content (%) of different branded PLGAs as assessed by 1HNMR spectroscopy (CDCl3, 500 MHz). A, B and C represent these groups of PLGAs with L/G ratio of 50/50, 75/25 and 100/0, respectively.","description":"","filename":"fig2.jpg","url":"https://assets-eu.researchsquare.com/files/rs-325988/v1/5dac62fae1b6196989707a8e.jpg"},{"id":7493252,"identity":"6e3bf2a0-d1ed-4010-8199-3086af809765","added_by":"auto","created_at":"2021-03-30 17:39:07","extension":"jpg","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":55357,"visible":true,"origin":"","legend":"13CNMR (CDCl3, 500 MHz) spectra of two representative PLGAs with acid-/ester-modified end-cap. A is Expansorb® DLG 50-2A and B is Expansorb® DLG 50-2E. The red arrow directs carbon signal at upfield chemical shift (14 ppm) of the methyl group at the terminal of aliphatic ester bond.","description":"","filename":"fig3.jpg","url":"https://assets-eu.researchsquare.com/files/rs-325988/v1/2e99ab4afb070459556362c6.jpg"},{"id":7492371,"identity":"a7a47c76-81b3-460f-a4fc-39aa4433c16b","added_by":"auto","created_at":"2021-03-30 17:30:07","extension":"jpg","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":44269,"visible":true,"origin":"","legend":"13CNMR spectra (CDCl3, 500 MHz) of carbonyl regions of glycolic mer units of the representative Expansorb® DLG 50-2E. The red area is intensity of the carbonyl peak of glycolic mers adjacent to lactic mers, while the blue zone represents the intensity of the carbonyl peak of a glycolic mers adjacent to another glycolic mers.","description":"","filename":"fig4.jpg","url":"https://assets-eu.researchsquare.com/files/rs-325988/v1/ab92e9764ac6acfe095e029d.jpg"},{"id":7492375,"identity":"a9e3e288-e353-4678-8e4d-41e085286bdf","added_by":"auto","created_at":"2021-03-30 17:30:08","extension":"jpg","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":83920,"visible":true,"origin":"","legend":"Blockiness values of PLGA polymers by 13CNMR spectroscopy (CDCl3, 500 MHz).","description":"","filename":"fig5.jpg","url":"https://assets-eu.researchsquare.com/files/rs-325988/v1/1d67c9bfa44ef82ced75d8d4.jpg"},{"id":7492374,"identity":"7195369f-ac67-4f7e-8ecf-6d2b4e2890c9","added_by":"auto","created_at":"2021-03-30 17:30:07","extension":"jpg","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":57235,"visible":true,"origin":"","legend":"13CNMR spectra (hexafluoro-2-propanol/benzenze-d6, 500 MHz) of the carbonyl regions of PLGA polymer (representative is Expansorb® DLG 50-5A). Shown as the arrows, the areas of pink (L-G), brown (L-L), blue (G-G) and red (G-L) represent the intensities of the carbonyl peak of lactic mer units adjacent to glycolic mers units, lactic adjacent to lactic, glycolic adjacent to glycolic, and glycolic adjacent to lactic, respectively.","description":"","filename":"fig6.jpg","url":"https://assets-eu.researchsquare.com/files/rs-325988/v1/4b09fae54245ddb998d850c1.jpg"},{"id":13613701,"identity":"a986aa8b-7f59-4818-9a95-1cb0f5fb1f05","added_by":"auto","created_at":"2021-09-17 06:38:08","extension":"pdf","order_by":1,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":970787,"visible":true,"origin":"","legend":"","description":"","filename":"JingManuscriptfinal3.pdf","url":"https://assets-eu.researchsquare.com/files/rs-325988/v1_covered.pdf"},{"id":7492638,"identity":"fb7bf9b7-012b-4c8e-bcd9-669b647f5459","added_by":"auto","created_at":"2021-03-30 17:33:07","extension":"jpg","order_by":2,"title":"","display":"","copyAsset":false,"role":"supplement","size":58647,"visible":true,"origin":"","legend":"","description":"","filename":"GraphicalAbstract.jpg","url":"https://assets-eu.researchsquare.com/files/rs-325988/v1/6eecbe706e796f93075aee09.jpg"},{"id":7492013,"identity":"7559ec8b-a93b-494a-87a9-4ef8879092c8","added_by":"auto","created_at":"2021-03-30 17:27:08","extension":"pdf","order_by":5,"title":"","display":"","copyAsset":false,"role":"supplement","size":1826516,"visible":true,"origin":"","legend":"","description":"","filename":"SupportInformationJS07272020spsf.pdf","url":"https://assets-eu.researchsquare.com/files/rs-325988/v1/f92a2ef552290ef9ac26d229.pdf"}],"financialInterests":"","formattedTitle":"Characterization of Commercial PLGAs by NMR Spectroscopy","fulltext":[{"header":"Full Text","content":"\u003cp\u003eDue to technical limitations, full-text HTML conversion of this manuscript could not be completed. 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