Bioavailability testing of a newly developed clindamycin oral suspension in a pediatric porcine model.

Background: Clindamycin's bitter taste and odor is known to affect treatment adherence in children. Recently, a formulation of clindamycin HCl complexed with ion exchange resin IRP 69 was shown to mask the bitter taste. Because of the potential benefit of this formulation for children, a pilot study using a porcine model was conducted to evaluate its relative bioavailability. Methods: A randomized two-way crossover study design using six (n = 6) healthy male piglets 10-12 kg was used to evaluate the absorption profiles and pharmacokinetic parameters of clindamycin from the resinate complex formulation (Test) compared to a commercialized reference suspension. A dose of 15 mg/kg was administered orally by gastric gavage to each piglet followed by repeated blood sampling over 12 h. A wash-out period of 48 h occurred between treatments. Plasma concentration vs. time data was analyzed by non-compartmental analysis. Results: The mean relative bioavailability of clindamycin from the resinate formulation was 78.8%. A two-tailed, paired Student t test yielded a p < 0.05 for AUC∞ and Tmax parameters. A two one-sided test (TOST) suggested a difference in AUC∞ and Cmax for the Test formulation compared to the reference formulation according to the FDA's criteria for bioequivalence. Conclusion: The bioavailability of clindamycin from this novel oral formulation supports continued evaluation of the drug in humans for potential pediatric applications.

Skeletal toxicity associated with chronic ethanol exposure in a rat model using total enteral nutrition.

Chronic alcohol abuse decreases bone mass, inhibits osteoblast differentiation and function, increases fracture incidence, and delays fracture healing. Four studies were designed to use intragastric ethanol delivery as part of a total enteral nutrition (TEN) system to determine the negative systemic effects of chronic ethanol on 1) the rat skeleton and 2) local rapid bone formation during limb lengthening (distraction osteogenesis, DO). In study 1, three-point bending tests demonstrated that after 75 days of ethanol exposure, the tibiae had significantly lower load to failure versus control diet (p = 0.0006) or ad libitum chow-fed rats (p = 0.0029). Study 2 examined alcohol's effects on the density and cross-sectional area of the proximal tibial metaphysis using peripheral quantitative computed tomography and found that after 25 days of ethanol exposure the trabecular volumetric bone mineral density (p = 0.011) and cortical cross-sectional area (p = 0.011) were lower compared with controls. In study 3, a comparison of distracted tibial radiographs and histological sections demonstrated ethanol-related decreases in both gap mineralization (p = 0.03) and bone column formation (p = 0.01). Histological comparisons in study 4 reproduced the ethanol-related deficits in new bone formation during DO (p = 0.001). These results indicate that the TEN system is a viable model to study ethanol's effects on the skeleton and that chronic ethanol delivery via TEN decreases trabecular bone density, cortical area, and mature bone strength. Also, the DO studies demonstrate, for the first time, that chronic ethanol inhibits rapid bone formation during limb lengthening.

Interleukin-1 and tumor necrosis factor antagonists attenuate ethanol-induced inhibition of bone formation in a rat model of distraction osteogenesis.

Chronic ethanol exposure inhibits rapid bone formation during distraction osteogenesis (DO; fracture and limb lengthening) and decreases volumetric bone mineral density (BMD) in a model of intragastric dietary infusion [total enteral nutrition (TEN)] in the rat. The hypothesis tested herein was that overexpression of interleukin (IL)-1beta and tumor necrosis factor (TNF)-alpha mediates these deleterious effects of ethanol on the rat skeleton. Two studies (study 1, female rats; study 2, male rats) were performed to test the potential protective effects of the IL-1 and TNF antagonists: IL-1 receptor antagonist (IL-1ra) and 30-kDa polyethylene glycol-conjugated soluble TNF receptor type 1 (sTNFR1). All rats were infused with a liquid diet +/- ethanol (EtOH) and underwent tibial fractures and DO. During distraction, the animals received a combination of IL-1ra (1.8-2.0 mg/kg/day) and sTNFR1 (2.0 mg/kg/2 days) or vehicle. A comparison of distracted tibial histological sections demonstrated 1) significant antagonist-related increases in bone column formation over the EtOH controls (studies 1 and 2), and 2) restoration of new bone equivalent to that of the TEN controls (study 2). In contrast, examination of intact proximal tibial metaphyses by peripheral quantitative computerized tomography revealed decreases in volumetric BMD of both EtOH control and EtOH antagonist groups (study 2). These results demonstrate that short-term systemic administration of IL-1 and TNF antagonists together protect rapid bone formation during DO from the deleterious effects of chronic ethanol but are ineffective in regard to intact bone homeostasis.