泊洛沙姆中聚乙二醇含量测定

Application Note- Pulsar 003 Determination of the Polyoxyethylene(POE) Percentage in Poloxamers Background Poloxamers are an important category of polymers with significant applications in industry， especially forpharmaceutical， cosmetic and personal care products.The most common uses are related to its surfactantproperties. In the cosmetics and personal care products， Poloxamers are used for various formulationsincluding mouthwashes， lens cleaning solutions， skin cleansers， shampoos and conditioners. In thepharmaceutical industry， Poloxamers are used as suspension and emulsifying agents， coating materialsand importantly as components of drug delivery systems. The United States Pharmacopeia and TheNational Formulary (USP-NF) specifies 5 different types of poloxamers with different chain lengths of x and y (see Figure 1). Poloxamers are non-ionic block copolymers comprising acentral polyoxypropylene block flanked by two polyoxyethyleneblocks (figure 1). The central block is hydrophobic while theflanking blocks are hydrophilic resulting in a polymer which is anamphiphile and suitable for use as a non-ionic surfactant. Theamphiphilic character of the polymer is dependent on the chainlengths and can be tailored for specific applications. Figure 1： Structure of generic poloxamer Poloxamers are identified by their poloxamer number whichtakes the form "P abc"， where the number ab multiplied by100 is the mass per mole of polyoxypropylene in the polymerand c multiplied by 10 is the percentage of polyoxyethylene.For example， poloxamer p188， contains 1800 g/molpolyoxypropylene and 80% polyoxyethylene. Figure 2： 'H spectrum of poloxamer 188 in CDCL， Analysis The method for performing the NMR analysis involvescollecting a 1-dimensional 1H spectrum and integrating theregion around 1.1 ppm (region 1) corresponding to the -CH，group on the polyoxypropylene block and the region around3.7 ppm (region 2) corresponding to the -CH，-and -CH-groups on all three blocks. The percentage of polyoxyethylene in the polymercan be evaluated from 3300a/(330+58) where o=(12 /11)-1 and /1 and /2 are the integrals of regionone and two respectively. The method relies on integrating regions of the spectrumcontaining multiple peaks， but does not require that thesepeaks are fully resolved， simply that region one and region twoare well separated. Figure 2 shows the 1H spectrum of poloxamer 188 acquired at1.4 T， 1H resonance frequency of 60 MHz. The data is a singlescan collected over a large spectral width， 5.2 KHz with 64Kcomplex data points that are zero filled on acquisition. Thespectrum shows that the two integral regions are sufficientlywell separated to allow integration. The results of integrating the spectra of four commercially availablepoloxamers are given in table 1. The reproducibility of the NMR results wasdetermined by collecting 16 spectra for each sample and calculating the% of polyoxyethylene from each data set. An average value and standarddeviation were determined from these results. The estimate show excellentcomparison with the values implied by the poloxamer. Name Poloxamer number % POE(NMR) %POE(p-number) Kolliphor P188 P188 82.1±0.6 80 Kolliphor P407 P 407 72.4±0.4 70 Pluronic F127 P 367 73.8±0.6 70 Synperonic F108 P 308 83.4±0.8 80 Table 1： % of polyoxyethylene in a poloxamer determined by NMR at 60 MHz.The numbers are compared to the values associated with the poloxamer number. Oxford InstrumentsIndustrial Analysis For more informationplease email： industrial@oxinst.com UKTubney Woods， Abingdon， Oxfordshire， OX13 5QX，UK Tel： +44 1865 393 200 China Room 1/E， Building 1， Xiangzhang Garden，No. 248 Donglan Road，Shanghai 201102， China Tel：+86 21 6073 2925 India 11， Marwah’s Complex，Andheri East，Mumbai，400072， IndiaTel.： +91 22 4253 5100 Japan Haseman Bldg，Tokyo， 135-0047， Japan Tel： +81 3 5245 3251 Singapore 10 Ubi Crescent， Singapore， 408564， Singapore Tel： +65 6337 6848 USA 300 Baker Avenue， Suite 150， Concord， Mass 01742，USA