Novel Technique For Synthesis Of Hydroxypropyl Methylcellulose Phthalate (HPMCP) And Preparation Of Aqueous HPMCP Dispersion

Hydroxypropyl methylcellulose phthalate (HPMCP) was prepared in classic Glacial Acetic Acid-Sodium Acetate system and new organic solvent system respectively, with HPMC as starting material and phthalic anhydride as functional graft monomer, which meet for the requirements of the Pharmacopoeia. IR test indicated that the product is the target product HPMCP. The experiments proved that the phthalyl content can be controlled by the dosage of phthalic anhydride. The reaction temperature should not be too high or too low, while high temperature will cause the reaction of the second carboxyl and low temperature can not provide enough power to the catalyst. By comparison, organic system has more benefits than Glacial Acetic Acid-Sodium Acetate system. It has higher yield than the Glacial Acetic Acid-Sodium Acetate system. The solvent it used does not corrode the equipment. It's easier to wash the product and easier to control the content of free acid in organic system. The solvent can be recycled and so avoid the environment pollution caused by solvent discharge.Hydroxypropyl methylcellulose phthalate (HPMCP) prepared was used as the starting material to prepare HPMCP water dispersion by water emulsion method, during which none of the organic solvent was used. TEM test showed HPMCP water dispersion latex particle is near-spherical. DLS test indicated that with the increase of the dosage of emulsification, the latex particle has more uniform micelle particles. SEM test showed that HPMCP water dispersion dissociate film has high compact-ability. Stretching test indicated that the HPMCP water dispersion with better particle size distribution have better mechanical property. The water dispersion with HPMC as emulsifier has excellent mechanical property. HPMCP water dispersion dissociate film has better film forming property, and HPMCP water dispersion dissociate films with different phthalyl contents were all insoluble in the simulated gastric fluid within 2 hours, which meets the requirement of China pharmacopeia. The solution rate of HPMCP water dispersion dissociate film can be accelerated with increasing the phthalyl content.