ASTM_F_2602_-_13.pdf

Designation:F260213Standard Test Method forDetermining the Molar Mass of Chitosan and Chitosan Saltsby Size Exclusion Chromatography with Multi-angle LightScattering Detection(SEC-MALS)1This standard is issued under the fixed designation F2602;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope1.1 This test method covers the determination of the molarmass of chitosan and chitosan salts intended for use inbiomedical and pharmaceutical applications as well as in tissueengineered medical products(TEMPs)by size exclusion chro-matography with multi-angle laser light scattering detection(SEC-MALS).Aguide for the characterization of chitosan saltshas been published as Guide F2103.1.2 Chitosan and chitosan salts used in TEMPs should bewell characterized,including the molar mass and polydisper-sity(molar mass distribution)in order to ensure uniformity andcorrect functionality in the final product.This test method willassist end users in choosing the correct chitosan for theirparticular application.Chitosan may have utility as a scaffoldor matrix material for TEMPs,in cell and tissue encapsulationapplications,and in drug delivery formulations.1.3 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.1.4 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2F2103 Guide for Characterization and Testing of ChitosanSalts as Starting Materials Intended for Use in Biomedicaland Tissue-Engineered Medical Product Applications2.2 United States Pharmacopeia/National Formulary:3 Chromatography2.3 National Institute of Standards and Technology:4NIST SP811 Special Publication:Guide for the Use of theInternational System of Units(SI)3.Terminology3.1 Definitions:3.1.1 chitosan,na linear polysaccharide consisting of(14)linked 2-acetamido-2-deoxy-D-glucopyranose(Glc-NAc)and 2-amino-2-deoxy-D-glucopyranose(GlcN).Chito-san is a polysaccharide derived by N-deacetylation of chitin.3.1.2 degree of deacetylation,nthe fraction or percentageof glucosamine units(GlcN:deacetylated monomers)in achitosan polymer molecule.3.1.3 molar mass average,nthe given molar mass(M)ofa chitosan will always represent an average of all of themolecules in the population.The most common ways toexpress the molar mass are as the number average(Mn)and themass average(Mw).The two averages are defined by thefollowing equations:Mn5(iNiMi(iNiandMw5(iwiMi(iwi5(iNiMi2(iNiMi(1)where:Ni=number of molecules having a specific molar mass Mi,andwi=mass of molecules having a specific molar mass Mi.3.1.3.1 DiscussionIn a polydisperse molecular populationthe relation Mw Mnis always valid.The coefficient Mw/Mnisreferred to as the polydispersity index,and will typically be inthe range 1.5 to 3.0 for commercial chitosans.NOTE1The term molecular weight(abbreviated MW)is obsolete andshould be replaced by the SI(Systme Internationale)equivalent of either1This test method is under the jurisdiction ofASTM Committee F04 on Medicaland Surgical Materials and Devices and is the direct responsibility of SubcommitteeF04.42 on Biomaterials and Biomolecules for TEMPs.Current edition approved Aug.1,2013.Published September 2013.Originallyapproved in 2008.Last previous edition approved in 2008 as F2602081.DOI:10.1520/F2602-13.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.3Available from United States Pharmacopeia and National Formulary,U.S.Pharmaceutical Convention,Inc.(USPC),Rockville,MD.4Available from National Institute of Standards and Technology(NIST),100Bureau Dr.,Stop 1070,Gaithersburg,MD 20899-1070,http:/physics.nist.gov/cuu/Units/bibliography.html.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 relative molecular mass(Mr),which reflects the dimensionless ratio of themass of a single molecule to an atomic mass unit(see ISO 31-8),or molarmass(M),which refers to the mass of a mole of a substance and istypicallyexpressedasgrams/mole.Forpolymersandothermacromolecules,use of the symbols Mw,Mn,and Mzcontinue,referringto mass-average molar mass,number-average molar mass,and z-averagemolar mass,respectively.For more information regarding proper utiliza-tion of SI units,see NIST SP811.4.Significance and Use4.1 The degree of deacetylation of chitosan,as well at themolar mass and molar