Tests

Standards

1

Characteristics

A yellow crystalline powder hygroscopic

2

identification

TLC

Sulphuric acid yellow colour reaction

Choride’s reaction

3

Acidity

PH 2.0-3.0

4

Absorbance

300-330

5

Specific optical rotation

-105º~ -`120º

6

Heavy metals

Not more than 50PPM

7

Light-absorbing impurities

Not more than 0.07

8

Related substances

Methacycline HCL

Not more than2.0%

6-epi doxycycline

Not more than 2.0%

Other impurities

Not more than 0.5%

9

Ethanol

4.3%-6.0%

10

Sulphated ash

Not more than 0.4%

11

Water

1.4%-2.8%

12

Assay (ankydrous ethanol free)

88.0%-94.0%