Source and content
This product is 2-hydroxypropyl ether methyl cellulose. According to the difference in the content of methoxy and hydroxypropyl, HPMC is divided into four types of substitution, namely 1828, 2208, 2906 and 2910. The content of each substituted methoxy (- OCH3) and hydroxypropyloxy (- OCH2CHOHCH3) shall comply with the provisions of the attached table according to the calculation of dried products. [1]
character
This product is white or almost white fibrous or granular powder; Odorless.
This product is almost insoluble in anhydrous ethanol, ether and acetone; It swells into a clear or slightly turbid colloidal solution in cold water. [1]
identify
(1) Take 1g of this product, heat 100mL of water (80~90 ℃), stir constantly, cool in an ice bath, and form a viscous liquid; Take 2mL and put it into a test tube, slowly add 1mL of 0.035% anthrone sulfuric acid solution along the tube wall, and place it for 5 minutes, and the blue-green ring appears at the interface of the two solutions.
(2) Take an appropriate amount of viscous liquid under identification (1), pour it on the glass plate, and form a tough film after the water evaporates. [1]
inspect
1. PH
Take 1.0g of this product (calculated as dry product), add 50g of water at 90 ℃ while stirring, after cooling, adjust the solution to 100g with water, stir until it is completely dissolved, and determine according to law (Appendix VI H, Part II, Pharmacopoeia 2010), the pH value should be 5.0~8.0.
2. Viscosity
Take 10.0g of this product, calculate as dry product, add 90 ℃ water to make the total weight of sample and water 500.0g, make 2.0% (g/g) suspension, fully stir for about 10 minutes until the particles are completely evenly dispersed and wetted, cool in an ice bath, continue to stir for 40 minutes during the cooling process, remove bubbles by centrifugation, and add cold water to adjust the weight if necessary; Use a single-cylinder rotary viscometer (samples with viscosity less than 100 Pa · s can be determined by NDJ-1, samples with viscosity greater than or equal to 100 Pa · s can be determined by NDJ-8S, or other suitable and qualified viscometers), at 20 ℃ ± 0.1 ℃, according to the law (the second method of Appendix VI G in Part II of the 2010 Pharmacopoeia), and the viscosity should be 80%~120% of the marked viscosity if the marked viscosity is less than 600 mPa · s; If the marked viscosity is greater than or equal to 600mPa · s, the viscosity shall be 75%~140% of the marked viscosity.
3 Insoluble matter in water
Take 1.0g of this product, put it into a beaker, add 100mL of hot water at 80~90 ℃, and after swelling for about 15 minutes, cool it in an ice bath, add 300mL of water (if necessary, properly increase the volume of water to ensure that the solution is filtered), and fully stir it. Filter it with No. 1 vertical-melting glass crucible dried to constant weight at 105 ℃, wash the beaker with water, put the washing solution into the above vertical-melting glass crucible, filter it, and dry it to constant weight at 105 ℃, leaving no more than 5mg (0.5%) of residue.
4 Loss on drying
Take this product and dry it at 105 ℃ for 2 hours, and the weight loss shall not exceed 5.0% (Appendix VIII L, Part II, Pharmacopoeia 2010).
5 Ignition residue
Take 1.0g of this product and check according to the law (Appendix VIII N, Part II, Pharmacopoeia 2010), and the residue shall not exceed 1.5%.
6 Heavy metals
Take the residue left under the burning residue item and check according to the law (the second method in Appendix VIII H of Part II of the 2010 Pharmacopoeia), and the heavy metal content shall not exceed 20 parts per million.
7 Arsenic salt
Take 1.0g of this product, add 1.0g of calcium hydroxide, mix it, add water and stir it evenly. After drying, burn it with a small fire to carbonize it, then burn it at 600 ℃ to completely ash it, cool it, add 5mL of hydrochloric acid and 23mL of water to dissolve it, and check according to the law (method 1, Appendix VIII J, Part II, Pharmacopoeia 2010), which should meet the requirements (0.0002%).
Content determination
1. Methoxy
Determine according to methoxy, ethoxy and hydroxypropyl determination method (Appendix VII F, Part II, Pharmacopoeia 2010). If the second method (volumetric method) is used, take this product, weigh it accurately, and measure it according to the law. The measured methoxy amount (%) is deducted from the hydroxypropyl amount (%) and (31/75 × 0.93).
2. Hydroxypropoxy
Determine according to methoxy, ethoxy and hydroxypropyl determination method (Appendix VII F, Part II, Pharmacopoeia 2010). If the second method (volumetric method) is used, take about 0.1g of this product, weigh it accurately, and determine according to law.
