JP XVIII Official Monographs / Metformin Hydrochloride Tablets 1329
Assay To an exactly measured volume of Metenolone Hydrochloride in 10 mL of water, and use this solution as
Enanthate Injection, equivalent to about 0.1 g of meteno- the sample solution. Pipet 1 mL of the sample solution, and
lone enanthate (C27H42O3), add chloroform to make exactly add water to make exactly 50 mL. Pipet 1 mL of this solu-
100 mL. Pipet 5 mL of this solution, add chloroform to tion, add water to make exactly 10 mL, and use this solution
make exactly 50 mL, and use this solution as the sample as the standard solution (1). Pipet 5 mL of the standard solu-
solution. Weigh accurately about 0.1 g of metenolone enan- tion (1), add water to make exactly 10 mL, and use this solu-
thate for assay, previously dried in a desiccator (in vacuum, tion as the standard solution (2). Separately, to 0.10 g of 1-
phosphorus (V) oxide) for 4 hours, and prepare the standard cyanoguanidine add water to make exactly 50 mL. Pipet 1
solution in the same manner as directed for the preparation mL of this solution, add water to make exactly 20 mL, and
of the sample solution. Pipet 3 mL each of the sample solu- use this solution as the standard solution (3). Perform the
tion and standard solution, add exactly 10 mL of isoniazid test with these solutions as directed under Thin-layer Chro-
TS, add methanol to make exactly 20 mL, and allow to stand matography <2.03>. Spot 10 mL each of the sample solution
for 60 minutes. Determine the absorbances, AT and AS, of and standard solutions (1), (2) and (3) on a plate of cellulose
the solutions from the sample solution and standard solu- for thin-layer chromatography. Develop the plate with a
tion, respectively, at 384 nm as directed under Ultraviolet- mixture of 4-methyl-2-pentanone, 2-methoxyethanol, water
visible Spectrophotometry <2.24>, using a solution obtained and acetic acid (100) (30:20:5:3) to a distance of about 10
by proceeding with 3 mL of chloroform as the blank. cm, air-dry the plate, then dry at 1059C for 10 minutes.
Spray evenly sodium pentacyanonitrosylferrate (III)-potas-
Amount (mg) of metenolone enanthate (C27H42O3)
sium hexacyanoferrate (III) TS on the plate: the spot other
＝ M S × AT / AS
than the principal spot obtained from the sample solution is
MS: Amount (mg) of metenolone enanthate for assay not more intense than the spot from the standard solution
taken (1), the number of them showing more intense than the spot
from the standard solution (2) is not more than two, and the
Containers and storage Containers—Hermetic containers.
spot from the sample solution appeared at the position cor-
Storage—Light-resistant.
responding to the spot from the standard solution (3) is not
more intense than the spot from the standard solution (3).
Metformin Hydrochloride Loss on drying <2.41> Not more than 0.5z (1 g, 1059C,
3 hours).
メトホルミン塩酸塩
Residue on ignition <2.44> Not more than 0.1z (1 g).
Assay Weigh accurately about 0.1 g of Metformin Hydro-
chloride, previously dried, dissolve in 40 mL of acetic acid
(100), add 40 mL of acetic anhydride, and titrate <2.50> with
0.05 mol/L perchloric acid VS (potentiometric titration).
C4H11N5.HCl: 165.62 Perform a blank determination in the same manner, and
1,1-Dimethylbiguanide monohydrochloride make any necessary correction.
[1115-70-4]
Each mL of 0.05 mol/L perchloric acid VS
＝ 4.141 mg of C4H11N5.HCl
Metformin Hydrochloride, when dried, contains
not less than 98.5z and not more than 101.0z of Containers and storage Containers—Tight containers.
metformin hydrochloride (C4H11N5.HCl).
Description Metformin Hydrochloride occurs as white,
crystals or crystalline powder. Metformin Hydrochloride Tablets
It is freely soluble in water, sparingly soluble in acetic acid
メトホルミン塩酸塩錠
(100), and slightly soluble in ethanol (99.5).
Melting point: about 2219C (with decomposition).
Metformin Hydrochloride Tablets contain not less
Identification (1) Determine the absorption spectrum of a
than 95.0z and not more than 105.0z of the labeled
solution of Metformin Hydrochloride (1 in 100,000) as di-
amount of metformin hydrochloride (C4H11N5.HCl:
rected under Ultraviolet-visible Spectrophotometry <2.24>,
165.62).
and compare the spectrum with the Reference Spectrum:
both spectra exhibit similar intensities of absorption at the Method of preparation Prepare as directed under Tablets,
same wavelengths. with Metformin Hydrochloride.
(2) Determine the infrared absorption spectrum of Met-
Identification Shake an amount of powdered Metformin
formin Hydrochloride as directed in the potassium chloride
Hydrochloride Tablets, equivalent to 250 mg of Metformin
disk method under Infrared Spectrophotometry <2.25>, and
Hydrochloride, with 25 mL of 2-propanol, and filter.
compare the spectrum with the Reference Spectrum: both
Evaporate the filtrate under reduced pressure in a water bath
spectra exhibit similar intensities of absorption at the same
at 409C, and determine the infrared absorption spectrum of
wave numbers.
the residue as directed in the potassium chloride disk method
(3) A solution of Metformin Hydrochloride (1 in 50)
under Infrared Spectrophotometry <2.25>: it exhibits absorp-
responds to Qualitative Tests <1.09> for chloride.
tion at the wave numbers of about 3370 cm－1, 3160 cm－1,
Purity (1) Heavy metals <1.07>—Proceed with 2.0 g of 1627 cm－1, 1569 cm－1 and 1419 cm－1.
Metformin Hydrochloride according to Method 1, and per-
Uniformity of dosage units <6.02> It meets the requirement
form the test. Prepare the control solution with 2.0 mL of
of the Mass variation test.
Standard Lead Solution (not more than 10 ppm).
(2) Related substances—Dissolve 2.5 g of Metformin Dissolution Being specified separately when the drug is
The JP Drugs are to be tested according to the provisions given in the pertinent monographs, General Notices, General Rules for Crude Drugs,
General Rules for Preparations, and General Tests for their conformity to the Japanese Pharmacopoeia. (See the General Notices 5.)
