1、USP 88 生物实验88 BIOLOGICAL REACTIVITY TESTS, IN VIVO The following tests are designed to determine the biological response of animals to elastomerics, plastics, and other polymeric material with direct or indirect patient contact, or by the injection of specific extracts prepared from the material und
2、er test. It is essential to make available the specific surface area for extraction. When the surface area of the specimen cannot be determined, use 0.1 g of elastomer or 0.2 g of plastic or other material for every mL of extraction fluid. Also, it is essential to exercise care in the preparation of
3、 the materials to be injected or instilled to prevent contamination with microorganisms and other foreign matter. Three tests are described. The Systemic Injection Test and the Intracutaneous Test are used for elastomeric materials, especially to elastomeric closures for which the appropriate Biolog
4、ical Reactivity Tests, In Vitro 87 have indicated significant biological reactivity. These two tests are used for plastics and other polymers, in addition to a third test, the Implantation Test, to test the suitability of these materials intended for use in fabricating containers and accessories the
5、reto, for use in parenteral preparations, and for use in medical devices, implants, and other systems.These three tests are applied to materials or medical devices, if there is a need for classification of plastics and other polymers based on in vivo biological reactivity testing.For the purpose of
6、this chapter, these definitions apply: the Sample is the specimen under test or an extract prepared from such a specimen. A Blank consists of the same quantity of the same extracting medium that is used for the extraction of the specimen under test, treated in the same manner as the extracting mediu
7、m containing the specimen under test. A Negative Control is a specimen that gives no reaction under the conditions of the test.CLASSIFICATION OF PLASTICS Six Plastic Classes are defined (see ). This classification is based on responses to a series of in vivo tests for which extracts, materials, and
8、routes of administration are specified. These tests are directly related to the intended end-use of the plastic articles. The choice of extractants is representative of the vehicles in preparations with which the plastics are likely to be in contact. The classification facilitates communication amon
9、g suppliers, users, and manufacturers of plastics by summarizing the tests to be performed for containers for injections and medical devices if a need for classification exists.Table 1. Classification of Plastics Plastic ClassesTests to be ConductedIIIIIIIVVVITest MaterialAnimalDoseProcedurexxxxxxEx
10、tract of Sample in Sodium Chloride InjectionMouse50 mL/kgA (IV)xxxxxxRabbit or Guinea Pig0.2 mL/animal at each of 10 or 6 sitesB (IC) ?xxxxxExtract of Sample in 1 in 20 Solution of Alcohol in Sodium Chloride InjectionMouse50 mL/kgA (IP)?xxxxxRabbit or Guinea Pig0.2 mL/animal at each of 10 or 6 sites
11、B (IC) ?x?xxExtract of Sample in Polyethylene Glycol 400Mouse10 g/kgA (IP)?xxRabbit or Guinea Pig0.2 mL/animal at each of 10 or 6 sitesB (IC) ?xxxxExtract of Sample in Vegetable OilMouse50 mL/kgA (IP)?xxxRabbit or Guinea Pig0.2 mL/animal at each of 10 or 6 sitesB (IC)?x?xImplant strips of SampleRabb
12、it4 strips/animalC ?x?xImplant SampleRat2 Samples/animal Ca ? Tests required for each class are indicated by “x” in appropriate columns. b ? Legend: A (IP)Systemic Injection Test (intraperitoneal); B (IC)Intracutaneous Test (intracutaneous); CImplantation Test (intramuscular or subcutaneous implanta
13、tion). With the exception of the Implantation Test, the procedures are based on the use of extracts that, depending on the heat resistance of the material, are prepared at one of three standard temperatures: 50, 70, and 121. Therefore, the class designation of a plastic must be accompanied by an ind
14、ication of the temperature of extraction (e.g., IV-121, which represents a class IV plastic extracted at 121, or I-50, which represents a class I plastic extracted at 50).Plastics may be classified as USP Plastic Classes IVI only on the basis of the response criteria prescribed in .This classificati
15、on does not apply to plastics that are intended for use as containers for oral or topical products, or that may be used as an integral part of a drug formulation. does not apply to natural elastomers, which are to be tested in Sodium Chloride Injection and vegetable oils only.The Systemic Injection
16、Test and the Intracutaneous Test are designed to determine the systemic and local, respectively, biological responses of animals to plastics and other polymers by the single-dose injection of specific extracts prepared from a Sample. The Implantation Test is designed to evaluate the reaction of livi
17、ng tissue to the plastic and other polymers by the implantation of the Sample itself into animal tissue. The proper preparation and placement of the specimens under aseptic conditions are important in the conduct of the Implantation Test.These tests are designed for application to plastics and other
18、 polymers in the condition in which they are used. If the material is to be exposed to any cleansing or sterilization process prior to its end-use, then the tests are to be conducted on a Sample prepared from a specimen preconditioned by the same processing.Factors such as material composition, proc
19、essing and cleaning procedures, contacting media, inks, adhesives, absorption, adsorption and permeability of preservatives, and conditions of storage may also affect the suitability of a material for a specific use. Evaluation of such factors should be made by appropriate additional specific tests
20、to determine the suitability of a material for its intended use.USP Reference Standards 11 USP High-Density Polyethylene RS. Extracting Media sodium chloride injection (see monograph). Use Sodium Chloride Injection containing 0.9% of NaCl. 1 in 20 solution of alcohol in sodium chloride injection. po
21、lyethylene glycol 400 (see monograph). vegetable oil Use freshly refined Sesame Oil (see monograph) or Cottonseed Oil (see monograph) or other suitable vegetable oils. drug product vehicle (where applicable). water for injection (see monograph). NoteThe Sesame Oil or Cottonseed Oil or other suitable
22、 vegetable oil meets the following additional requirements. Obtain, if possible, freshly refined oil. Use three properly prepared animals, and inject the oil intracutaneously in a dose of 0.2 mL into each of 10 sites per animal, and observe the animals at 24, 48, and 72 h following injection. Rate t
23、he observations at each site on the numerical scale indicated in Table 2. For the 3 rabbits or guinea pigs (30 or 18 injection sites), at any observation time, the average response for erythema is not greater than 0.5 and for edema is not greater than 1.0, and no site shows a tissue reaction larger
24、than 10 mm in overall diameter. The residue of oil at the injection site should not be misinterpreted as edema. Edematous tissue blanches when gentle pressure is applied. Table 2. Evaluation of Skin Reactions Erythema and Eschar FormationScoreNo erythema0Very slight erythema (barely perceptible)1Wel
25、l-defined erythema2Moderate to severe erythema3Severe erythema (beet-redness) to slight eschar formation (injuries in depth)4Edema FormationScoreNo edema0Very slight edema (barely perceptible)1Slight edema (edges of area well defined by definite raising)2Moderate edema (raised approximately 1 mm)3Se
26、vere edema (raised more than 1 mm and extending beyond the area of exposure)4a? Draize JH, Woodward G, Calvery HO. Methods for the study of irritation and toxicity of substances applied topically to the skin and mucous membranes. J Pharmacol Exp Ther 1944;82:377390. b? Excludes noninflammatory (mech
27、anical) edema from the blank or extraction fluid. Apparatus The apparatus for the tests includes the following. autoclave Use an autoclave capable of maintaining a temperature of 121 2.0, equipped with a thermometer, a pressure gauge, a vent cock, a rack adequate to accommodate the test containers a
28、bove the water level, and a water cooling system that will allow for cooling of the test containers to about, but not below, 20 immediately following the heating cycle. oven Use an oven, preferably a forced-circulation model, that will maintain operating temperatures of 50 or 70 within 2. extraction
29、 containers Use only containers, such as ampuls or screw-cap culture test tubes, of Type I glass. If used, culture test tubes are closed with screw caps having suitable elastomeric liners. The exposed surface of the elastomeric liner is completely protected with an inert solid disk 0.050.075 mm in t
30、hickness. A suitable disk may be fabricated from a polytef resin. Preparation of Apparatus Cleanse all glassware thoroughly with chromic acid cleansing mixture, or if necessary, with hot nitric acid, followed by prolonged rinsing with water. Clean cutting utensils by an appropriate method (e.g., suc
31、cessive cleaning with acetone and methylene chloride) prior to use in subdividing a specimen. Clean all other equipment by thorough scrubbing with a suitable detergent and prolonged rinsing with water. Render containers and equipment used for extraction, and in transfer and administration of test material, sterile and dry by a suitable process. NoteIf ethylene oxide is used as the sterilizing agent, allow adequate time for complete degassing. Procedure preparation of sample Both the Systemic Injection Test and the Intracutaneous Test may be performed usin
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