ABSTRACT
Objective: In the present study, transdermal nanoemulsion (NE) gel of lovastatin was investigated for its anti-osteoporosis effect on the long bones of rat i.e. tibia. Methods: Male wistar rats (n=30, weighing 180-200g) were taken for this study and grouped as: 1) control (normal saline daily), 2) Dex (dexamethasone sodium; 25 mg/kg subcutaneously twice a week), 3) Dex+LNG5 (lovastatin nanoemulsion gel; 5 mg/kg/d transdermally daily), 4) Dex+LNG10 (lovastatin nanoemulsion gel; 10 mg/kg/d transdermally daily), and 5) Dex+ALN (alendronate sodium; 0.03 mg/kg/d orally daily). All the treatments were carried out for 60 d. At the end of the experiment, all animals were anesthetized using diethyl ether and collected blood samples from retro-orbital venous plexus of rats in dry eppendorf tubes followed by the sacrifice of animals by cervical dislocation method and collected tibia bones of both the legs for analysis. Results: Bone formation biomarkers (OC: osteocalcin, b-ALP: bone-specific alkaline phosphatase, PINP: N-terminal propeptides of type I procollagen) were significantly improved and resorption biomarkers (CTx: C-terminal cross-linking telopeptides of type-I collagen, TRAcP5b: isoform 5b of tartarate resistant acid phosphatase) were significantly reduced in the LNG5 (p<0.05) and LNG10 (p<0.05) treatment groups when compared to Dex. In vivo anti-osteoporotic results demonstrated the formation of new bone in osteoporotic rat tibias. Biomechanical strength testing demonstrated increased load-bearing capacity of rat tibias in the treated animals in comparison with the osteoporotic group (p<0.05 for LNG5 and p<0.01 for LNG10). Conclusion: Thus, the transdermal NE gel formulation of lovastatin demonstrated the greater potential for the treatment of osteoporosis.
ABSTRACT
OBJECTIVE: To investigate the pharmacokinetics of triptolide gels, nanoemulsions and nanoemulsion gels by simultaneous skin and blood microdialysis in rats. METHODS: The microdialysis systems include linear probes and vascular probes which are used for measuring the recovery of triptolide in skin and blood, respectively. Linear probe and vascular probe were implanted in SD rats after abdominal hair removal. Triptolide gels, nanoemulsions and nanoemulsion gels were administered to SD rats. The probe was continuously perfused with PBS(pH 7.4) at a flow rate of 3 μL•min-1. Dialysate samples were collected every 30 min and continuously performed for 12 h. The dialysis samples were determined by LC-MS. RESULTS: The AUC0-t(s) of triptolide nanoemulsions and nanoemulsion gels were significantly higher than those of triptolide gels in skin and blood. Moreover, compared with the concentration of triptolide nanoemulsions in skin and blood, triptolide was released more smoothly from nanoemulsion gels, providing a sustained release effect and an improved bioavailability. CONCLUSION: The technique of simultaneous skin and blood microdialysis is able to detect the concentration of drug in the skin and blood of rats, which provides a new method for the pharmacokinetic study of tripolide.