BACKGROUND A new complexing protein-free botulinum toxin Type A (CBoNT) with the same mechanism of action as the botulinum toxin complex onabotulinumtoxinA (OBoNT) and complexing protein-free incobotulinumtoxinA (IBoNT) was recently developed. OBJECTIVE To compare the local paresis and chemodenervation efficacy of 3 different botulinum toxin Type A preparations in mice. MATERIALS AND METHODS Efficacy and duration of action of CBoNT, OBoNT, and IBoNT after a single intramuscular injection to the right gastrocnemius was evaluated by digit abduction score (DAS) and compound muscle action potential (CMAP) assays. RESULTS Mouse DAS and CMAP responses were comparable between CBoNT and OBoNT, indicating similar paresis and chemodenervation efficacy, as well as duration of action. Both botulinum toxins showed significantly higher efficacy and longer duration of action than IBoNT. Similarly, mean DAS potency of CBoNT (ED 50 : 3.85 ± 0.34 U/kg) and OBoNT (ED 50 : 4.13 ± 0.07 U/kg) were significantly higher compared with IBoNT (ED 50 : 6.70 ± 0.83 U/kg). CONCLUSION CBoNT displays the same efficacy as OBoNT as shown by their comparable chemodenervation and local paretic effects, and demonstrates superior efficacy and duration of action compared with IBoNT. Likewise, CBoNT has comparable DAS potency to OBoNT and is superior to IBoNT.

The production of recombinant anti-HIV peptide, T-20, in Escherichia coli was optimized by statistical experimental designs (successive designs with multifactors) such as 2(4-1) fractional factorial, 2(3) full factorial, and 2(2) rotational central composite design in order. The effects of media compositions (glucose, NPK sources, MgSO4, and trace elements), induction level, induction timing (optical density at induction process), and induction duration (culture time after induction) on T-20 production were studied by using a statistical response surface method. A series of iterative experimental designs was employed to determine optimal fermentation conditions (media and process factors). Optimal ranges characterized by %T-20 (proportion of peptide to the total cell protein) were observed, narrowed down, and further investigated to determine the optimal combination of culture conditions, which was as follows: 9, 6, 10, and 1 mL of glucose, NPK sources, MgSO4, and trace elements, respectively, in a total of 100 mL of medium inducted at an OD of 0.55-0.75 with 0.7 mM isopropyl-beta-D-thiogalactopyranoside in an induction duration of 4 h. Under these conditions, up to 14% of T-20 was obtained. This statistical optimization allowed the production of T-20 to be increased more than twofold (from 6 to 14%) within a shorter induction duration (from 6 to 4 h) at the shake-flask scale.

Purpose Hyaluronic acid (HA) is the most common injectable dermal filler used for soft-tissue augmentation, and can be removed non-surgically by directly injecting hyaluronidase. In this study, the hyaluronidase-mediated degradation of different types of HA fillers implanted subcutaneously at the back of hairless mice having filler residence time of four days or three months were compared. Methods Two sites at the back of female hairless mice were subcutaneously implanted with 0.1-mL of one of the seven HA fillers (NLL, NL, NDL, NVL, and ND, JUV X+ , and RES LYFT ) and injected with 30 IU or 60 IU hyaluronidase per 0.1-mL filler after reaching a filler residence time of 4 or 91 days, respectively. Filler bolus projection was measured using three-dimensional optical imaging over a 72 h period, and the implantation sites were histologically examined 2 weeks after hyaluronidase injection. Results Following hyaluronidase injection, all seven HA fillers showed a rapid decrease of filler volume within 24 h, and complete degradation was confirmed by histological examination after 2 weeks. There was no significant difference in filler volume reduction rate among the seven HA fillers, and no evidence of macroscopic or microscopic adverse effects were observed at the implantation sites. Conclusion All seven HA fillers show comparable susceptibility to hyaluronidase-mediated degradation. HA fillers with prolonged filler residence time may require a higher dose of hyaluronidase to achieve efficient degradation owing to tissue integration.

Human serum albumin (HSA) has been widely used as a pharmaceutical excipient in Botulinum toxin serotype A (BoNT/A) products that are indicated for use in therapeutics and cosmetics. However, HSA as a human-derived material has some concerns, such as the potential risk of transmission of infectious agents, an insufficient supply, and difficulty in maintaining a certain quality. For those reasons, newly developed BoNT/A products (CORETOX®, Medytox, Inc., Republic of Korea) contained polysorbate 20, a non-human-derived excipient, to replace the HSA. However, most safety studies of polysorbate 20 have been conducted with non-invasive routes of administration, and thus there are a few studies on the safety of polysorbate 20 when administered intramuscularly. To secure the in vivo safety profile of polysorbate 20, a four-week repeated intramuscular dose toxicity study (0.02, 0.1, and 0.4 mg/kg, one injection every two weeks for a total of three injections) was conducted in 66 Sprague-Dawley (SD) rats. An intradermal irritation study was further conducted with 18 New Zealand White (NZW) rabbits. The toxicological evaluation of HSA (0.06 and 0.12 mg/kg) was also carried out as a comparative substance. Systemic and local toxicities were not observed in any of the SD rats or NZW rabbits based on clinical signs, body weight, hematology, clinical biochemistry, macroscopic findings on necropsy, histopathology of the injection site, and allergic reactions. The current study suggested that intramuscular administration of polysorbate 20 was considered to be safe at a level similar to that of HSA, which has an in vivo safety profile accumulated over the years. This provided the basis for the in vivo safety profile of polysorbate 20 administered intramuscularly and the scientific reliability of the use of polysorbate 20 as an alternative to HSA, which is used as an excipient for various pharmaceuticals in terms of its safety.

Dermal fillers are gel-type substances for nonsurgical medical-device use to achieve facial rejuvenation. Currently, the most widely used skin fillers are hyaluronic-acid-based dermal fillers. This study aimed to explain the change in the volume of injected dermal fillers by developing a mathematical kinetic model for various dermal fillers. The kinetics of the injected fillers were separated by a biphasic phenomenon. We attributed an increase in filler volume to the hydration of hyaluronic acid molecules and injection-site reaction and a decrease in volume to enzyme-mediated degradation. To explain these in vivo characteristics of dermal fillers, we proposed a two-compartment model, divided into a depot compartment (where the filler was injected) and a subcutaneous compartment (an observation compartment where the fillers swell and degrade), assuming that the swelling and degradation occurred in accordance with the swelling and degradation rate constants, respectively. The model was developed using five hyaluronic-acid-based dermal fillers and NONMEM. We determined that the rate-limiting step for the complete degradation of the dermal fillers in vivo was the swelling phase, as described by the swelling rate constant (Kswell). This study could enable scientists developing novel dermal fillers to predict the in vivo behavior of fillers.