Improved bleeding scores using Gelfoam(®) Powder with incremental concentrations of bovine thrombin in a swine liver lesion model.

Topical hemostatic agents are used intra-operatively to prevent uncontrolled bleeding. Gelfoam(®) Powder contains a hemostatic agent prepared from purified pork skin gelatin, the efficacy of which is increased when combined with thrombin. However, the effect of increasing concentrations of thrombin on resultant hemostasis is not known. This study sought to evaluate the ability of various concentrations of thrombin in combination with Gelfoam Powder to control bleeding using a swine liver lesion model. Ten pigs underwent a midline laparotomy. Circular lesions were created in the left medial, right medial, and left lateral lobes; six lesions per lobe. Gelfoam Powder was hydrated with Thrombin-JMI(®) diluted to 250, 375, and 770 IU/mL. Each concentration was applied to two lesion sites per lobe. Bleeding scores were measured at 3, 6, 9, and 12 min using a 6-point system; comparison of bleeding scores was performed using ANOVA with the post hoc Tukey test. The bleeding scores with thrombin concentrations at 770 IU/mL were significantly lower than at 250 and 375 IU/mL at all four time points. The percentage of biopsies with a clinically acceptable bleeding score rose from 37.9, 46.6, and 71.2 % at 3 min to 55.2, 69.0, and 88.1 % at 12 min in the 250, 375, and 770 IU/mL thrombin groups, respectively. The study showed that the hemostatic response to thrombin was dose-related: using higher concentrations of thrombin with Gelfoam Powder yielded improved hemostasis, as determined by lower bleeding scores.

Embryo-Fetal Developmental Toxicity Studies with Pregabalin in Mice and Rabbits.

Pregabalin was evaluated for potential developmental toxicity in mice and rabbits. Pregabalin was administered once daily by oral gavage to female albino mice (500, 1250, or 2500 mg/kg) and New Zealand White rabbits (250, 500, or 1250 mg/kg) during organogenesis (gestation day 6 through 15 [mice] or 6 through 20 [rabbits]). Fetuses were evaluated for viability, growth, and morphological development. Pregabalin administration to mice did not induce maternal or developmental toxicity at doses up to 2500 mg/kg, which was associated with a maternal plasma exposure (AUC0-24 ) of 3790 µg•hr/ml, ≥30 times the expected human exposure at the maximum recommended daily dose (MRD; 600 mg/day). In rabbits, treatment-related clinical signs occurred at all doses (AUC0-24 of 1397, 2023, and 4803 µg•hr/ml at 250, 500, and 1250 mg/kg, respectively). Maternal toxicity was evident at all doses and included ataxia, hypoactivity, and cool to touch. In addition, abortion and females euthanized moribund with total resorption occurred at 1250 mg/kg. There were no treatment-related malformations at any dose. At 1250 mg/kg, compared with study and historical controls, the percentage of fetuses with retarded ossification was significantly increased and the mean number of ossification sites was decreased, which correlated with decreased fetal and placental weights, consistent with in utero growth retardation. Therefore, the no-effect dose for developmental toxicity in rabbits was 500 mg/kg, which produced systemic exposure approximately 16-times human exposure at the MRD. These findings indicate that pregabalin, at the highest dose tested, was not teratogenic in mice or rabbits.

Developmental Toxicity Studies with Pregabalin in Rats: Significance of Alterations in Skull Bone Morphology.

Pregabalin was administered to pregnant Wistar rats during organogenesis to evaluate potential developmental toxicity. In an embryo-fetal development study, compared with controls, fetuses from pregabalin-treated rats exhibited increased incidence of jugal fused to maxilla (pregabalin 1250 and 2500 mg/kg) and fusion of the nasal sutures (pregabalin 2500 mg/kg). The alterations in skull development occurred in the presence of maternal toxicity (reduced body weight gain) and developmental toxicity (reduced fetal body weight and increased skeletal variations), and were initially classified as malformations. Subsequent investigative studies in pregnant rats treated with pregabalin during organogenesis confirmed the advanced jugal fused to maxilla, and fusion of the nasal sutures at cesarean section (gestation day/postmating day [PMD] 21) in pregabalin-treated groups. In a study designed to evaluate progression of skull development, advanced jugal fused to maxilla and fusion of the nasal sutures was observed on PMD 20-25 and PMD 21-23, respectively (birth occurs approximately on PMD 22). On postnatal day (PND) 21, complete jugal fused to maxilla was observed in the majority of control and 2500 mg/kg offspring. No treatment-related differences in the incidence of skull bone fusions occurred on PND 21, indicating no permanent adverse outcome. Based on the results of the investigative studies, and a review of historical data and scientific literature, the advanced skull bone fusions were reclassified as anatomic variations. Pregabalin was not teratogenic in rats under the conditions of these studies.