๐ ็ธฝ็ฎ้ ๏ฝ ๐ ่ฑๆๅๆ๏ผๆฌ็ฏ๏ผ ๏ฝ ๐ ๅฎๆด็ฟป่ญฏ ๏ฝ โญ ็ฒพ่ฏ็ญ่จ
Product preparation
Product preparation
Reconstitution and storage of the product play an important role in achieving maximal safety and efficacy. Original recommendations from the manufacturer, as well as Centers for Disease Control and Prevention (CDC) guidelines, suggested that BTX be used within 4 hours of reconstitution and that each vial should only be used to treat a single patient. However, multiple clinical studies have since established that refrigerated storage postreconstitution for periods of weeks does not decrease efficacy,23โ26 freezethawing of reconstituted BTX is allowable,27 mechanical agitation does not damage the active molecule,28 use of a single vial for multiple patients with appropriate precautions does not increase infectious risk,29 and prolonged storage of reconstituted product under appropriate conditions does not lead to detectable microbial growth.30 Expert consensus guidelines therefore recommend that a vial of BTX can be refrigerated or refrozen for at least 4 weeks before injection without significant risk for contamination or decreased effectiveness, and that a single vial can be used to treat multiple patients, assuming appropriate handling.31,32 Other important considerations regarding the preparation of BTX include the reconstitution medium and different reconstitution techniques for different commercial preparations. Using preservative- containing sterile normal saline for reconstitution significantly reduces subsequent injection pain and is therefore recommended.33,34 Particular attention needs to be paid to INCO vials which require both swirling and inversion of the vial in order to dissolve all of the product within.35 INCO is also unique among current FDA-approved BTX-A preparations in that room temperature storage (25ยฐC) for 1 week appears to have no impact on treatment
efficacy.36 Volume of dilution in clinical practice ranges from 1 to 10 mL per vial, with 2.5 to 3 mL being most commonly employed.37 Variations in dilution do not impact efficacy as long as absolute number of units remains equivalent,38 although injection of smaller volumes promotes more precise technique.39