Optical Rotation Test

CD Formulation specializes in providing analytical testing services for drugs, including physicochemical constants. We have extensive experience in testing the spin properties of drugs and can help our clients quickly analyze the spin properties of drugs and determine the purity of drugs based on their spin properties.

About Optical Rotation

Many drugs are optically active, i.e. the plane of polarized light passing through the liquid or solution can cause the phenomenon of rotation, so that the plane of polarized light rotates to the left or right, and the number of degrees of deflection is called spin. Rotational photometry, that is, the determination of the drug's rotational activity, is a simple method to distinguish optical isomers. This method is also an important indicator for identification and purity check. There are many factors that affect the spin of a substance, besides the characteristics of the compound, it is also related to the measurement wavelength, the concentration of the test solution through which the polarized light passes and the thickness of the liquid layer, as well as the temperature during the measurement.

Determination of Optical Rotation

Test procedure

• The luminescence can be stabilized only after at least 20 minutes after the start of the sodium lamp of the spinner, and the measurement or reading should be read after the sodium lamp is stabilized.
• Blank determination of pure liquid samples are measured with a dry blank measuring tube to correct the zero point of the instrument, while solution samples are corrected with a blank solvent to correct the zero point of the instrument. Before each measurement should be blank calibration with solvent, after the measurement, and then calibrated once to determine whether there is a change in the zero point during the measurement.
• When measuring the rotational brightness, the rotational brightness reading should be repeated 3 times, and the average value should be taken to calculate the specific rotational degree according to the following formula.

Determination of content

Operate according to the regulations under each species, prepare 2 test solutions for parallel test, the concentration of the test solution should be consistent with the requirement as far as possible, and the subsequent test is consistent with the test of the drug's rotational strength.

Applications

Drug identification

For drugs with spin, the test item of "specific spin" is usually included under "properties". Determination of specific rotation value can be used to identify drugs or determine the degree of purity of drugs.

Impurity analysis

Drugs with optical isomers generally have the same physicochemical properties, but their spin properties are different, there are generally levator, dextrorotatory and racemic, by measuring the spin of impurities in the drug, the purity of the drug can be checked.

Content determination

The drug with the spin property, especially in the absence of other better methods to determine its content, can be determined by the spin photometric method.

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