HPMC (Hydroxypropyl Methylcellulose) yog ib hom semi-synthetic polysaccharide polymer uas yog dav siv hauv tshuaj, khoom noj khoom haus, tshuaj lom neeg kev lag luam thiab lwm yam kev lag luam. Nws cov yam ntxwv tawg yog ib qho ntawm qhov kub ntawm kev tshawb fawb thiab kev siv.
1. Molecular qauv thiab solubility yam ntxwv ntawm HPMC
HPMC yog cov dej-soluble polymer compound tau los ntawm etherification hloov ntawm cellulose. Nws chav tsev yog β-D-glucose, uas txuas nrog 1,4-glycosidic bonds. Cov qauv tseem ceeb ntawm HPMC yog muab los ntawm cov cellulose ntuj, tab sis ib feem ntawm nws cov hydroxyl pawg yog hloov los ntawm methoxy pawg (-OCH₃) thiab hydroxypropyl pawg (-CH₂CH(OH)CH₃), yog li nws nthuav tawm tus cwj pwm sib txawv ntawm cov cellulose ntuj.
Cov qauv molecular ntawm HPMC muaj qhov cuam tshuam loj rau nws cov solubility. Qhov degree ntawm kev hloov pauv (DS, Degree of Hloov) thiab molar hloov pauv (MS, Molar Hloov) ntawm HPMC yog qhov tseem ceeb uas txiav txim siab nws cov yam ntxwv solubility. Qhov siab dua qhov kev hloov pauv, ntau pawg hydroxyl nyob rau hauv cov molecule yog hloov los ntawm hydrophobic methoxy los yog hydroxypropyl pawg, uas ua rau kom cov solubility ntawm HPMC hauv cov kuab tshuaj organic thiab txo cov solubility hauv dej. Ntawm qhov tsis sib xws, thaum qhov kev hloov pauv qis qis, HPMC yog hydrophilic ntau dua hauv dej thiab nws qhov kev sib cais sai dua.
2. Dissolution mechanism ntawm HPMC
Lub solubility ntawm HPMC nyob rau hauv dej yog ib tug complex lub cev thiab tshuaj txheej txheem, thiab nws dissolution mechanism feem ntau muaj xws li cov nram qab no cov kauj ruam:
Kev ntub dej theem: Thaum HPMC los rau hauv kev sib cuag nrog dej, cov dej molecules yuav xub tsim ib zaj duab xis hydration ntawm HPMC los qhwv HPMC hais. Hauv cov txheej txheem no, cov dej molecules cuam tshuam nrog hydroxyl thiab methoxy pawg hauv HPMC molecules los ntawm hydrogen bonds, ua rau HPMC molecules maj mam wetted.
Cov theem o: Nrog rau kev nkag mus ntawm cov dej molecules, HPMC cov khoom pib nqus dej thiab o, ntim nce, thiab cov saw hlau molecular maj mam loosen. Lub peev xwm o ntawm HPMC cuam tshuam los ntawm nws qhov hnyav molecular thiab hloov pauv. Qhov loj dua qhov hnyav molecular, lub sijhawm o ntev dua; qhov muaj zog ntawm hydrophilicity ntawm qhov hloov pauv, qhov ntau dua qhov o.
Kev tawg theem: Thaum HPMC molecules nqus dej txaus, cov saw hlau molecular pib tshem tawm ntawm cov khoom thiab maj mam tawg hauv cov tshuaj. Qhov ceev ntawm cov txheej txheem no cuam tshuam los ntawm cov yam ntxwv xws li kub, nplawm tus nqi thiab hnyav zog.
HPMC feem ntau qhia tau zoo solubility hauv dej, tshwj xeeb tshaj yog nyob rau hauv chav tsev kub. Txawm li cas los xij, nws tsim nyog sau cia tias thaum qhov kub nce mus rau qee theem, HPMC yuav nthuav tawm "thermal gel" tshwm sim, uas yog, kev solubility txo qis thaum qhov kub nce. Qhov no yog vim lub zog txav ntawm cov dej molecules ntawm qhov kub thiab txias thiab txhim kho hydrophobic kev sib cuam tshuam ntawm HPMC molecules, ua rau kev sib koom ua ke ntawm kev sib txuas thiab tsim cov qauv gel.
3. Yam cuam tshuam rau kev solubility ntawm HPMC
Kev solubility ntawm HPMC cuam tshuam los ntawm ntau yam, suav nrog nws lub cev thiab tshuaj lom neeg thiab cov xwm txheej sab nraud. Cov yam tseem ceeb muaj xws li:
Kev hloov pauv qib: Raws li tau hais los saum toj no, hom thiab tus lej ntawm cov hloov pauv ntawm HPMC cuam tshuam ncaj qha rau nws cov solubility. Qhov ntau substituents, tsawg dua hydrophilic pawg nyob rau hauv lub molecule thiab cov solubility tsis zoo. Ntawm qhov tsis sib xws, thaum muaj cov khoom siv tsawg dua, qhov hydrophilicity ntawm HPMC tau txhim kho thiab solubility zoo dua.
Molecular Luj: Qhov hnyav molecular ntawm HPMC yog ncaj qha proportional rau nws lub sij hawm dissolution. Qhov loj dua qhov hnyav molecular, qhov qeeb ntawm cov txheej txheem dissolution. Qhov no yog vim HPMC cov saw hlau molecular uas muaj qhov hnyav molecular ntev dua thiab cov molecules yog nruj dua entangled, ua rau nws nyuaj rau cov dej molecules nkag mus, ua rau qeeb o thiab tawg tus nqi.
Kev daws qhov kub thiab txias: Kub yog ib qho tseem ceeb cuam tshuam rau kev solubility ntawm HPMC. HPMC yaj sai dua ntawm qhov kub thiab txias, thaum nyob rau ntawm qhov kub siab dua nws tuaj yeem tsim cov gel thiab txo nws cov solubility. Yog li ntawd, HPMC feem ntau yog npaj nyob rau hauv cov dej kub uas tsis muaj gelation ntawm qhov kub thiab txias.
Hom kuab tshuaj: HPMC tsis yog soluble hauv dej xwb, tab sis kuj soluble nyob rau hauv tej yam organic solvents, xws li ethanol, isopropyl cawv, thiab lwm yam. Raws li qhov xwm txheej ib txwm muaj, HPMC muaj cov dej tsis zoo hauv cov kuab tshuaj organic, thiab cov dej tsim nyog yuav tsum tau ntxiv los pab kev sib cais.
Tus nqi pH: HPMC muaj qee qhov kam rau pH tus nqi ntawm cov tshuaj, tab sis nyob rau hauv huab cua acid thiab alkali tej yam kev mob, lub solubility ntawm HPMC yuav raug cuam tshuam. Feem ntau hais lus, HPMC muaj qhov zoo dua solubility hauv pH ntau ntawm 3 txog 11.
4. Kev thov ntawm HPMC hauv ntau qhov chaw
Kev solubility ntawm HPMC ua rau nws muaj txiaj ntsig hauv ntau qhov chaw:
Pharmaceutical teb: HPMC feem ntau yog siv los ua cov ntaub ntawv txheej, cov nplaum thiab cov neeg ua haujlwm tso tawm rau cov tshuaj ntsiav tshuaj. Hauv cov txheej txheem tshuaj, HPMC tuaj yeem tsim cov yeeb yaj kiab zoo ib yam los txhim kho kev ruaj ntseg ntawm cov tshuaj; nyob rau hauv cov kev tsim tawm-tso tawm, HPMC tswj qhov kev tso tawm ntawm cov tshuaj los ntawm kev tswj nws qhov kev sib cais, yog li ua tiav kev xa tshuaj mus ntev.
Kev lag luam khoom noj khoom haus: Hauv cov khoom noj, HPMC yog siv los ua cov thickener, emulsifier thiab stabilizer. Vim tias HPMC muaj cov dej zoo solubility thiab kub stability, nws muaj peev xwm muab kev ntxhib los mos thiab saj ntawm ntau yam khoom noj. Tib lub sijhawm, qhov tsis yog-ionic ntawm HPMC tiv thaiv nws los ntawm kev cuam tshuam nrog lwm cov khoom xyaw thiab ua kom lub cev thiab tshuaj lom neeg ruaj khov ntawm cov zaub mov.
Kev lag luam tshuaj lom neeg txhua hnub: HPMC feem ntau siv los ua cov thickener thiab emulsifier hauv cov khoom xws li tshuaj zawv plaub hau, tshuaj pleev thiab tshuaj pleev ntsej muag. Nws zoo solubility nyob rau hauv dej thiab thickening nyhuv pab kom nws muab ib tug zoo heev kev paub siv. Tsis tas li ntawd, HPMC tuaj yeem sib koom ua ke nrog lwm cov khoom xyaw nquag los txhim kho kev ua haujlwm ntawm cov khoom.
Cov khoom siv hauv tsev: Hauv kev tsim kho kev lag luam, HPMC yog siv los ua cov thickener thiab cov dej tuav hauv cov cement mortars, pobzeb adhesives thiab coatings. HPMC tuaj yeem txhim kho kev ua haujlwm ntawm cov ntaub ntawv no, txuas ntxiv lawv lub sijhawm siv, thiab txhim kho lawv cov kev tiv thaiv tawg.
Raws li cov khoom siv polymer nrog zoo solubility, HPMC tus cwj pwm dissolution yog cuam tshuam los ntawm ntau yam, xws li cov qauv molecular, kub, pH nqi, thiab lwm yam. Nyob rau hauv ntau daim ntawv thov teb, cov solubility ntawm HPMC tuaj yeem ua kom zoo dua los ntawm kev kho cov yam ntxwv no kom tau raws li cov kev xav tau sib txawv. Lub solubility ntawm HPMC tsis tsuas yog txiav txim siab nws cov kev ua tau zoo nyob rau hauv aqueous daws, tab sis kuj ncaj qha cuam tshuam nws cov dej num nyob rau hauv cov tshuaj, zaub mov, tshuaj niaj hnub thiab kev lag luam.
Post lub sij hawm: Oct-14-2024