Hydroxyethyl cellulose (HEC) yog non-ionic, dej-soluble polymer muab los ntawm cellulose, ib txwm tshwm sim polymer pom nyob rau hauv cell phab ntsa ntawm cov nroj tsuag. Nws yog dav siv nyob rau hauv ntau yam lag luam xws li tshuaj, tshuaj pleev ib ce, pleev xim, nplaum, thiab khoom noj khoom haus vim nws cov yam ntxwv tshwj xeeb xws li thickening, stabilizing, thiab dej tuav lub peev xwm. Txawm li cas los xij, sib tham txog tus nqi pH ntawm HEC yuav tsum muaj kev nkag siab dav dua ntawm nws cov khoom, qauv, thiab kev siv.
Nkag siab txog Hydroxyethyl Cellulose (HEC):
1. Chemical Structure:
HEC yog synthesized los ntawm cov tshuaj tiv thaiv ntawm cellulose nrog ethylene oxide, ua rau cov kev taw qhia ntawm hydroxyethyl pawg (-CH2CH2OH) mus rau cellulose qaum.
Qhov degree ntawm kev hloov pauv (DS) yog hais txog qhov nruab nrab ntawm cov pawg hydroxyethyl ib chav tsev piam thaj hauv cov saw cellulose thiab txiav txim siab cov khoom ntawm HEC. Cov txiaj ntsig DS siab dua ua rau muaj dej ntau ntxiv thiab qis dua viscosity.
2. Khoom:
HEC yog soluble hauv dej thiab tsim cov kev daws teeb meem meej, uas ua rau nws haum rau ntau yam kev siv uas xav tau cov qauv pob tshab.
Nws nthuav tawm tus cwj pwm pseudoplastic, txhais tau tias nws cov viscosity txo qis hauv kev ntxhov siab, tso cai rau kev siv yooj yim thiab tuav.
Lub viscosity ntawm HEC cov kev daws teeb meem yog cuam tshuam los ntawm ntau yam xws li concentration, kub, pH, thiab muaj ntsev los yog lwm yam additives.
3. Kev siv:
Pharmaceuticals: HEC yog siv los ua cov thickener thiab stabilizer nyob rau hauv qhov ncauj thiab tshuaj pleev ib ce formulations xws li tshuaj pleev, cream, thiab suspensions.
Tshuaj pleev ib ce: Nws yog ib yam khoom muaj nyob rau hauv cov khoom tu tus kheej nrog rau cov tshuaj zawv plaub hau, tshuaj pleev ib ce, thiab cream vim nws cov thickening thiab emulsifying zog.
Xim thiab Txheej: HEC yog ntxiv rau cov xim, txheej, thiab cov nplaum los tswj cov viscosity, txhim kho cov khoom ntws, thiab txhim kho kev tsim cov yeeb yaj kiab.
Kev lag luam khoom noj khoom haus: Hauv cov khoom noj khoom haus, HEC ua haujlwm ua cov thickener, stabilizer, thiab emulsifier hauv cov khoom xws li kua ntses, hnav khaub ncaws, thiab khoom noj siv mis.
pH Tus nqi ntawm Hydroxyethyl Cellulose (HEC):
1. pH nyob ntawm:
Cov pH ntawm cov tshuaj uas muaj HEC tuaj yeem cuam tshuam nws tus cwj pwm thiab kev ua haujlwm hauv ntau yam kev siv.
Feem ntau, HEC ruaj khov tshaj pH dav, feem ntau ntawm pH 2 thiab pH 12. Txawm li cas los xij, pH huab cua yuav cuam tshuam rau nws cov khoom thiab kev ruaj ntseg.
2. Cov teebmeem pH ntawm viscosity:
Lub viscosity ntawm HEC cov kev daws teeb meem tuaj yeem yog pH-nyob, tshwj xeeb tshaj yog nyob rau qhov siab lossis qis pH.
Nyob ze ntawm qhov nruab nrab pH ntau (pH 5-8), HEC cov kev daws teeb meem feem ntau pom lawv cov viscosity siab tshaj plaws.
Ntawm qhov tsawg heev los yog siab pH qhov tseem ceeb, cov pob txha cellulose tuaj yeem raug hydrolysis, uas ua rau txo qis viscosity thiab stability.
3. Kev hloov pH:
Nyob rau hauv cov formulations qhov twg pH hloov yog tsim nyog, buffers feem ntau yog siv los tswj cov pH yam xav tau.
Feem ntau cov buffers xws li citrate lossis phosphate buffers yog sib xws nrog HEC thiab pab tswj nws cov khoom nyob rau hauv ib qho kev pH.
4. Kev txiav txim siab ntawm daim ntawv thov:
Formulators yuav tsum xav txog pH compatibility ntawm HEC nrog rau lwm cov khoom xyaw hauv formulation.
Qee qhov xwm txheej, kev hloov kho rau pH ntawm kev tsim yuav tsum tau ua kom zoo dua qhov ua tau zoo ntawm HEC.
Hydroxyethyl cellulose (HEC) yog ntau yam polymer nrog kev siv dav hauv ntau lub lag luam. Thaum nws cov pH ruaj khov feem ntau muaj zog tshaj ntau yam, pH siab tuaj yeem cuam tshuam nws qhov kev ua tau zoo thiab ruaj khov. Kev nkag siab txog pH dependence ntawm HEC yog qhov tseem ceeb rau kev tsim cov khoom lag luam zoo thiab ruaj khov hauv cov tshuaj, tshuaj pleev ib ce, pleev xim, nplaum, thiab khoom noj khoom haus. Los ntawm kev txiav txim siab pH sib raug zoo thiab siv cov tswv yim tsim nyog, HEC tuaj yeem txuas ntxiv ua cov khoom tseem ceeb hauv ntau hom kev siv.
Lub sij hawm xa tuaj: Plaub Hlis-15-2024