Absorbable Surgical Suture

This article is compiled based on the United States Pharmacopeia (USP) – 2025 Edition

Issued and maintained by the United States Pharmacopeial Convention (USP)

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1 DEFINITION 

Absorbable Surgical Suture is a sterile, exible strand prepared from collagen derived from healthy mammals or from a synthetic polymer. Suture prepared from synthetic polymer may be in either monolament or multilament form. It is capable of being absorbed by living mammalian tissue, but may be treated to modify its resistance to absorption. Its diameter and tensile strength correspond to the size designation indicated on the label, within the limits prescribed herein. It may be modied with respect to body or texture. It may be impregnated or treated with a suitable coating, softening, or antimicrobial agent. It may be colored by a color additive approved by the FDA. The collagen suture is designated as either Plain Suture or Chromic Suture. Both types consist of processed strands of collagen, but Chromic Suture is processed by physical or chemical means so as to provide greater resistance to absorption in living mammalian tissue. 

2 IMPURITIES 

Soluble Chromium Compounds 

Standard solution: 2.83 µg/mL of potassium dichromate in water 

Sample solution: 5 mL of the uid prepared as directed in the Extractable Color test 

Analysis: To 5 mL each of the Standard solution and Sample solution add 2 mL of a solution (1 in 100) of diphenylcarbazide in alcohol and 2 mL of 2 N sulfuric acid. 

Acceptance criteria: Any color that develops in the Sample solution is not more intense than that in the Standard solution [1 ppm of chromium (Cr)]. 

3 SPECIFIC TESTS 

[Note—If the Suture is packaged with a uid, make the required measurements for the rst four of the following tests within 2 min after removing it from the uid.] 

3.1 Length 

Sample: A length of Suture 

Analysis: Determine the length of the Sample without stretching. 

Acceptance criteria: The length of each strand is NLT 95.0% of the length stated on the label. 

Change to read: 

3.2 Sutures—Diameter 〈861〉 

Sample: 10 strands of Suture 

Analysis: Determine the diameter as directed in the chapter. 

Acceptance criteria 

Collagen suture: The average diameter, and NLT 20, of the 30 measurements on the 10-strand Sample are within the limits on average diameter in Table 1 for the size stated on the label. None of the individual observed measurements should be less than or greater than the limits on individual diameter in Table 1. 

Table 1. Collagen Suture 

^a USP sizes may not represent all sizes commercially available. For sizes other than those listed in this table, suture manufacturers must generate appropriate diameters and tensile strength data to support use. 

^b To convert from N to kg, divide N by 1.0197 and round to one signicant gure. 

Synthetic suture: The average diameter of the strands being measured is within the tolerances prescribed in Table 2 for the size stated on the label. None of the individual observed measurements should be less than or greater than the limits on individual diameter in Table 2. 

Table 2. Synthetic Suture 

^a USP sizes may not represent all sizes commercially available. For sizes other than those listed in this table, suture manufacturers must generate appropriate diameters and tensile strength data to support use. 

^b To convert from N to kg, divide N by 1.0197 and round to one signicant gure. 

^c The tensile strength of the specied USP size is measured by straight pull. 

3.3 Tensile Strength 〈881〉, Surgical Suture 

Sample: NLT 10 strands of Suture 

Analysis: Determine the tensile strength of the Sample as directed in the chapter. 

Acceptance criteria 

Collagen suture: The tensile strength, determined as the minimum strength for each individual strand tested and calculated as the average strength from any one lot, is as set forth in Table 1. If NMT 1 strand fails to meet the limit on individual strands, repeat the test with NLT 20 additional strands; the requirements of the test are met if none of the additional strands fall below the limit on individual strands, and if the average strength of all the strands tested does not fall below the stated limit in Table 1. 

Synthetic suture: The minimum tensile strength of each size of synthetic suture, calculated as the average strength from any one lot, is as set forth in Table 2. 

3.4 Sutures—Needle Attachment 〈871〉

Suture on which eyeless needles are swaged meets the requirements. 

3.5 Sterility Tests 〈71〉

Suture that is claimed to be sterile meets the requirements. 

Change to read: 

3.6 Extractable Color (if Suture is dyed) 

Matching solutions: Prepare by combining the colorimetric solutions (CS) in the proportions indicated in Table 3, and adding water, if necessary, to make 10.0 parts. [See Reagents, Indicators, and Solutions—Solutions, Colorimetric Solutions (CS) for composition.] 

Table 3. Matching Solutions 

2/16/25, 9:19 PM USP-NF Absorbable Surgical Suture 

Sample: NLT 250 mg of Suture 

Analysis: Place the Sample in a conical ask containing 1.0 mL of water for each 10 mg of the Sample. For microsutures use 2.5 mL of water for each 25 mg of the Sample. Close the ask, and allow it to stand at 37 ± 0.5° for 24 h. Cool. Decant the water from the Suture, and compare it with the Matching solution. Where brous extraneous material may affect the color, lter the solution before performing the color determination. 

Acceptance criteria: Any color present is not more intense than that of the appropriate Matching solution. (USP 1-Dec-2020) 

4 ADDITIONAL REQUIREMENTS 

Packaging and Storage: Preserve dry or in uid, in containers (packets) so designed that sterility is maintained until the container is opened. A number of such containers may be placed in a box. 

Labeling: The label of each individual container (packet) of Suture indicates the size, length, type of Suture, including the material composition as well as the physical conguration (e.g., monolament/multilament, twisted/braided), kind of needle (if a needle is included), number of Sutures (if multiple), lot number, and name of the manufacturer or distributor. If removable needles are used, the labeling so indicates. Suture size is designated by the metric size (gauge number) and the corresponding USP size. The label of the box indicates also the address of the manufacturer, packer or distributor, and the composition of any packaging uids used.