Milk Thistle Capsules
»Milk Thistle Capsules are prepared from Powdered Milk Thistle Extract.They contain not less than 90.0percent and not more than 110.0percent of the labeled amount of silymarin as silybin (C25H22O10),calculated as the sum of silydianin,silychristin,silybin A,silybin B,isosilybin A,and isosilybin B.
Packaging and storage— Preserve in tight,light-resistant containers.
Labeling— The label states the Latin binomial and,following the official name,the article from which the Capsules were prepared.The label also indicates the content of silymarin,in mg per Capsule.
Identification—
A:Thin-Layer Chromatographic Identification Test á201ñ—
Standard solution,Developing solvent system,and Procedure— Proceed as directed for the Identificationtest under Milk Thistle.
Test solution— Weigh and finely powder the contents of not fewer than 20Capsules.Transfer a portion of the powder,equivalent to about 50mg of silymarin,to a suitable container,add 10mLof methanol,shake for 1minute,and sonicate for 10minutes.Allow to stand for 15minutes before use.
B: The retention times of the peaks for silydianin,silychristin,silybin A,silybin B,isosilybin A,and isosilybin Bin the chromatogram of the Test solutioncorrespond to those in the chromatogram of Milk thistle standard solution,as obtained in the test for Content of silymarin.
Microbial enumeration á2021ñ— The total bacterial count does not exceed 104cfu per g,the total combined molds and yeasts count does not exceed 103cfu per g,and the enterobacterial count does not exceed 102per g.It meets the requirements of the tests for absence of Salmonellaspecies and Escherichia coli.
Disintegration and dissolution á2040ñ: meet the requirements for Dissolution.
pH7.5Phosphate buffer— Dissolve 27.6g of monobasic sodium phosphate and 6.08g of sodium hydroxide in water,and dilute with water to 4000mL.
Medium: pH7.5Phosphate buffercontaining 2%lauryl sulfate;900mL.
Apparatus 2: 100rpm.
Time: 45minutes.
Determine the amount of silymarin as silybin (C25H20O10)dissolved by employing the method in the test for Content of silymarin,making any necessary modifications.
Tolerances— Not less than 75%of the labeled amount of silymarin as silybin (C25H22O10)is dissolved in 45minutes.
Weight variation á2091ñ: meet the requirements.
Content of silymarin—
Solution A,Solution B,Mobile phase,Silybin standard solutions,and Chromatographic system— Proceed as directed in the test for Content of silymarinunder Milk Thistle.
Milk thistle standard solution— Dissolve an accurately weighed quantity of USP Powdered Milk Thistle Extract RSin methanol,sonicate for 20minutes,and dilute with methanol to obtain a solution having a known concentration of about 0.7mg of extract per mL.
Test solution— Weigh and finely powder the contents of not fewer than 20Capsules.Transfer an accurately weighed amount of the powder,equivalent to about 100mg of silymarin,to a 100-mLvolumetric flask,add 90mLof methanol,and sonicate for 20minutes with occasional shaking.Cool to 20,and dilute with methanol to volume.Filter through a membrane having a 0.45-µm or finer porosity.
Procedure— Proceed as directed in the test for Content of silymarinunder Milk Thistle,except to separately calculate the amount,in mg,of each relevant component of silymarin as silybin (C25H22O10)in the portion of Capsules taken by the formula:
100C,
in which the term,C,is as defined therein.Calculate the content of silymarin,in mg,in the portion of Capsules taken by adding the individual amounts.
Auxiliary Information— Staff Liaison:Gabriel I.Giancaspro,Ph.D.,Senior Scientist and Latin American Specialist
Expert Committee:(DSB)Dietary Supplements:Botanicals
USP28–NF23Page 2118
Pharmacopeial Forum:Volume No.29(2)Page 479
Phone Number:1-301-816-8343