Nanostructured Lipid Carrirs For Improved Oral Bioavailability Of Tilmicosin In Broilers

Nanosizing is one of the most important drug delivery platforms approaches for the commercial development of poorly soluble drug molecules.Though,Tilmicosin(TMS)is a macrolide antibiotic,which synthesized from tylosin and mainly used in poultry because of its antibacterial properties.However,its poor water solubility and bitterness restricted the clinical application on the veterinary side.Tilmicosin(TMS)has produced poor oral bioavailability and acts like a physical barrier and may decrease the absorption of the drug.Nanostructured lipid carriers(NLCs),are the promising drug delivery vehicle,offer an alternative system to traditional colloidal carriers in the nanoscience.In general,the aims of the present dissertation were to prepare tilmicosin-loaded NLCs using high-shearing and ultrasonication process and further characterized to evaluate their physical and chemical properties.Furthermore,we have also performed the pharmacokinetics and bioavailability of TMS-NLCs compared with 10%TMS(Marketed)in the broiler chickens(In vivo).Additionally,the effect of TMS-NLCs on intestinal drug permeability was performed in Caco-2 cell model(In vitro).Experiment 1:Preparation of tilmicosin-loaded nanostructured lipid carriersThe main purpose of the current study was to prepare the stable nanostructured lipid carrier(NLC)of TMS that would be able to overcome such hurdles.NLCs were prepared by using high shearing-ultra sonication.The formulation comprised of varying ratios of solid lipids(Palmitic acid,Lauric acid,Stearic acid)and oil(Oleic acid)was developed by high shear homogenization technique followed by ultrasonication.Extensive screening of surfactants is done by aqueous titration to select the surfactant with best emulsifying potential Tween-20 and Poloxamer-407.To optimize the concentration of lipids and surfactants,NLCs were evaluated for their particle size,PDI,zeta potential and%drug entrapment efficiency of optimized formulations.The results have revealed TMS-pNLC 272.7±1.55 nm,TMS1NLC 277± 1.55 nm,TMS-sNLC 262±4.03 in size respectively.Additionally,no significant changes were observed in the PDI,zeta potential and%drug entrapment efficiency of optimized formulations.This study demonstrated that proper selection of excipients(by aqueous titration)and method of preparation by cold step would lead to the successful production of three new TMS-NLCs with best distinctive properties.Experiment 2:Evaluation of tilmicosin nanostructured lipid carriers(TMS-NLCs)The aim of the present study was to investigate the characterization methods for three formulations of TMS-NLCs,which has been successfully prepared.The images of transmission electron microscopy revealed that the majority of TMS-NLCs exhibited nano sized spherical morphologies with narrow size distribution.No obvious changes in particle size and morphology and no chemical degradation of the drug ingredients were found.All three formulations of TMS-NLCs have not shown any clusters,and the physicochemical characteristics had no significant changes after being stored at room temperature,4? and 40? for 60 days,indicating the NLCs had good stability.The effect of pH on the particle size,PDI and zeta potential has shown no significant change at low and high pH in size and PDI of the NLCs as compared to the(NLCs in water)due to the steric stabilization effect of Polaxamer-407 and Tween-20.The compatibility of TMS-NLCs and other excipients were established using Differential Scanning Calorimetry.The FT-IR Spectroscopy technique was used to examine the thermal behavior of TMS-NLCs.The precise characterization suggested that TMS-NLCs have high-quality physicochemical characteristics and the use of different protocols did not affect TMS-NLCs morphology and dimensional distribution.Experiment 3:Tilmicosin nanostructured lipid carriers(TMS-NLCs):A promising drug delivery system in vivo and in vitro studyThe current study aimed to conduct in vivo pharmacokinetic experiments forty broiler chickens were divided into four groups,three as treatment and one as a control group(n=10).Pharmacokinetic studies after the oral deposition of a single dose of TMS-sNLCs(25 mg/kg)in broilers showed a significant increase in bioavailability as compared to the 10%TMS commercial drugs.The intestinal permeation and in vitro transport assay of tilmicosin loaded nanostructured lipid carriers(NLCs)in contrast to 10%TMS in Caco-2 cells,which is a model intestinal cell line for in vitro toxicology.In our results,we have revealed that TMS-sNLCs formulation increases the permeation across Caco-2 cell monolayer than the 10%TMS(Commercial drug).Concisely,three newly prepared TMSNLCs formulation TMS-pNLCs,TMS-lNLCs,and TMS-sNLCs significantly improved drug permeability.Particularly TMS-sNLCs formulation results are promising both in vitro and in vivo,which suggests an efficient delivery system for TMS.