Domestic HPMC uses a standard: China Pharmacopoeia (there is no difference in the model or specification of HPMC in 2005). USP is divided into four models (1828, 2208, 2906, 29 10). China Pharmacopoeia stipulates that "the content of methoxy (-OCH3) should be 19.0% ~ 30.0%, and the content of hydroxypropyl (-OCH2CHOHCH3) should be 4.0% ~ 12.0%". The gelation temperature of hydroxypropyl methylcellulose has great influence on the preparation and application of hydroxypropyl methylcellulose. It is necessary to find out the gelation temperature. When hydroxypropyl methylcellulose aqueous solution is heated, phase separation will occur at a specific temperature, forming gel precipitation with three-dimensional network structure; When cooling, the gel disappears and returns to the original solution state when it reaches below the specific temperature for gel formation. This temperature is the gelation temperature. Click to send samples for free.
If you have any related questions, please consult Haoshuo Chemical. Hebei Haoshuo Chemical Co., Ltd. was established on 201kloc-0/65438+1October 25th. The legal representative is Su Bingtao, whose business scope includes: production and sales of hydroxypropyl methylcellulose; Production and sales of R&D, cellulose ether (except dangerous chemicals) and pharmaceutical excipients (except dangerous drugs); Sales of chemical raw materials (except hazardous chemicals); Self-management and agency of import and export business of various commodities and technologies (except items prohibited by laws and administrative regulations); Projects restricted by laws and administrative regulations can only be operated after obtaining permission (projects that must be approved according to law can only be operated after being approved by relevant departments).