Comparative study of rheological properties and preclinical data of porous polycaprolactone microsphere dermal fillers.

BACKGROUND: In this study, a physical properties test and preclinical evaluation were performed on two polycaprolactone (PCL)-based dermal filler formulas. OBJECTIVE: This study was performed to compare the rheological characteristics, preclinical efficacy, and safety of a new PCL filler, SF-01, with a licensed PCL filler. METHODS: First, the viscoelasticity of the PCL filler was evaluated. Next, hairless mice were injected with fillers and evaluated for efficacy with a folliscope and PRIMOSLITE . Histological evaluation was conducted for 6 months to evaluate safety. RESULTS: In this evaluation, SF-01 was superior to a licensed PCL filler in initial volume increase rate and in vivo durability, and the migration of the injected filler was not confirmed. The elasticity (G*, G') and viscosity (G'') are also expected to be lower than those of a licensed PCL filler, thereby resulting in less foreign body sensation in the living body. CONCLUSION: SF-01 (porous PCL microsphere-based dermal filler) has been confirmed to be superior in durability and shape retention compared to the licensed PCL filler (nonporous PCL microsphere-based dermal filler), and the in vivo safety is equivalent.

In Vivo Comparison of MONOFIX, A Novel Barbed Suture with a Triangular Stopper, with Pre-existing Products in a Porcine Model.

STUDY OBJECTIVE: MONOFIX, a new absorbable barbed suture device, has a triangular stopper at the end to hold the suture to the tissue without hooking the looped end or knotting. The aim of this study was to compare the biomechanical strength and histologic features of MONOFIX with other barbed suture devices using a porcine model. DESIGN: Well-designed, controlled trial without randomization. SETTING: Animal laboratory in university hospital. SUBJECTS: Sixteen, 60-kg, mature female domestic pigs (skin closure group) and 5, 60-kg, mature female domestic pigs (fascial closure group). INTERVENTIONS: In the skin closure group, 3-0 MONOFIX versus 2 widely used 3-0 absorbable barbed sutures (3-0 V-Loc 180 or Stratafix). In the fascial closure group, 2-0 MONOFIX versus 1 widely used 2-0 absorbable barbed sutures (2-0 Stratafix). MEASUREMENTS AND MAIN RESULTS: In the skin closure group, the biomechanical wound strength of skin sutured with size 3-0 MONOFIX, V-Loc 180, or Stratafix was evaluated by postoperative day assessment (days 0, 3, 7, 14, and 28). In the fascial closure group, pigs underwent 2 paramedian incisions and were sutured with 2-0 MONOFIX or with 2-0 Stratafix to evaluate histologic reaction. At 6 weeks the tissues around the suture line were excised and microscopically evaluated. The biomechanical strength of the MONOFIX had similar tissue tensile strength compared with the control, regardless of postoperative day. In the fascial closure model, there was no significant difference in the average tissue reaction score between MONOFIX and Stratafix (1.2 ± .3 vs 1.3 ± .3, p = .478). CONCLUSION: This study demonstrated that MONOFIX has equivalent tensile strength and histologic reaction when compared with commonly used barbed suture devices. Accordingly, this preclinical study suggests that the use of MONOFIX is a safe alternative to other barbed suture devices.

Efficacy evaluation of SurgiGuard® in partially hepatectomized pigs.

BACKGROUNDS/AIMS: This study evaluated the hemostatic effects of a novel oxidized regenerated cellulose, SurgiGuard®, during liver surgery, using a reproducible and clinically relevant animal model. METHODS: Fifteen mini-pigs underwent left partial hepatectomy. They were randomized to treatment of the resected surface with SurgiGuard® (Group C [test], n=5), Surgicel® (Group B [reference], n=5), or nothing (Group A [control], n=5). Blood loss was measured 5, 7 and 9 min after resection. Time to hemostasis was recorded. Mini-pigs were necropsied 4 or 6 weeks postoperatively to evaluate toxicity changes and material dissolution. RESULTS: The median resected liver weight was 2.13 g (2.02-2.20) in control group, 2.04 g (2.01-2.13) in reference group, and 2.01 g (1.99-2.12) in test group (p=0.024). Median total blood loss was 57.18 g (52.02-59.54) in control group, 32.52 g (27.66-35.10) in reference group, and 35.52 g (25.70-38.71) in test group (p=0.008). Blood loss at 0-5 minutes and 7-9 minutes was significantly different between groups (p=0.009 and p=0.006, respectively). At necropsy, no hematomas, granulomas, or adhesions were noted in any group. Histopathological analysis revealed no changes suggesting toxicity related to SurgiGuard®. CONCLUSIONS: SurgiGuard® is as effective as Surgicel® in achieving hemostasis after porcine partial liver resection.

Development of docetaxel-loaded intravenous formulation, Nanoxel-PM™ using polymer-based delivery system.

Nanoxel-PM™, docetaxel-loaded methoxy-poly(ethylene glycol)-block-poly(d,l-lactide) (mPEG-PDLLA) micellar formulation was prepared in an effort to develop alternative, less toxic and efficacious Tween 80-free docetaxel formulation, and its pharmacokinetics, efficacy, and toxicity were evaluated in comparison with Taxotere® in preclinical studies. The mean diameter of the Nanoxel-PM™ was 10-50 nm and the polydispersity of samples exhibited a narrow size distribution and monodisperse unimodal pattern. Pharmacokinetic study in mice, rats and beagle dogs revealed that Nanoxel-PM™ exhibited similar pharmacokinetic profiles (C(max), AUC, t(1/2), CL, V(ss)) to Taxotere, and the relative mean AUC(t) and C(max) of Nanoxel-PM™ to Taxotere® were within 80-120%. Furthermore, excretion study in rats demonstrated that there was no statistically significant difference in the amount excreted in feces or urine as an unmetabolized docetaxel between Nanoxel-PM™ and Taxotere®. Its pharmacokinetic bioequivalence resulted in comparable anti-tumor efficacy to Taxotere® in human lung cancer xenografts H-460 in nude mice as well as in lung, ovary and breast cancer cell lines. Several animal toxicity studies on Nanoxel-PM™ compared with Taxotere® were carried out. In single dose rat and dog model and repeated dose mouse model, both Nanoxel-PM™ and Taxotere® exhibited similar toxic effects on hematology and body weight gain. On the other hand, vehicle related hypersensitivity reactions and fluid retentions were not observed when Nanoxel-PM™ was administered, unlike Taxotere®, in the beagle dog study. Based on these results, it is expected that Nanoxel-PM™ can reduce side effects of hypersensitivity reactions and fluid retention while retaining antitumor efficacy in cancer patients. Currently, Nanoxel-PM™ is under evaluation for bioequivalence with Taxotere® in a multi-center, open-label, randomized, crossover study.

Buprederm, a new transdermal delivery system of buprenorphine: pharmacokinetic, efficacy and skin irritancy studies.

PURPOSE: The pharmacokinetics, analgesic efficacy, and irritancy potential of Buprederm, a new transdermal delivery system of buprenorphine, was evaluated. METHODS: Single and multiple dose pharmacokinetic studies were conducted in mice and rabbits. The analgesic efficacy and skin irritation potential were determined by tail flick and writhing tests in mice and by the Draize dermal scoring system in rabbits. RESULTS: Fast absorption of buprenorphine into the bloodstream was observed in mice and rabbits after Buprederm application. The peak buprenorphine level in plasma was achieved between 1 and 24 h, and the effective therapeutic drug concentration was maintained for 72 h. No significant accumulation of buprenorphine was seen after multiple consecutive applications of patches to rabbits with a 4-day dosing interval. Buprederm induced prolongation of tail-flick latency in a dose- and time-dependent manner. Maximum analgesic effect was attained between 3 and 6 h and was maintained for 24 h after patch application. No skin irritation was demonstrated in rabbits after repeated Buprederm application. CONCLUSIONS: Buprederm was shown to be efficacious by achieving the effective buprenorphine concentration in the blood and brain sufficient to maintain an analgesic effect for 72 h, and was also shown to be safe following multiple applications.

Effects of 17beta-estradiol and tamoxifen on the selenoprotein phospholipid hydroperoxide glutathione peroxidase (PHGPx) mRNA expression in male reproductive organs of rats.

The selenoprotein phospholipid hydroperoxide glutathione peroxidase (PHGPx) is highly expressed in testes under gonadotropin control. The expression patterns of PHGPx mRNA by 17beta-estradiol (E2) as an estrogen and tamoxifen (Tam) as an estrogen antagonist were investigated in the reproductive organs of male rats. Twelve-week-old male Sprague-Dawley rats were subcutaneously injected with E2 (7.5 microg/kg/day) or Tam (5 mg/kg/day) for 1 week. The E2 treatment significantly increased the levels of PHGPx mRNA in both testes and prostates, whereas the Tam treatment significantly decreased the levels of PHGPx mRNA, compared to the vehicle control (p<0.01). The treatment with E2 or Tam slightly decreased the levels of PHGPx mRNA in epididymides. In histopathological examination, severe vacuolization and depletion of germ cells in the seminiferous tubules, cell debris in the tubular lumen, and mild proliferative changes in interstitial tissues were observed in the testes of Tam-treated rats, whereas only mild spermatogonial proliferation was observed in the seminiferous tubules of E2-treated rats. There were no typical histopathological changes in the epididymides of any of the laboratory rats but mild epithelial proliferation in the prostates of E2- and Tam-treated rats. These results suggest that PHGPx mRNA expression may be influenced by estrogen in the male reproductive organs.