Study On Etodolac Double-Layer Tablet

Etodolac is a chiral nonsteroidal anti-inflammatory drug that is available for the treatment of arthritis and the alleviation of pain clinically. In order to get effectiveness quickly and keep long impact, etodolac double-layer tablets with immediate-release layer and sustained-release layer are prepared.The content of etodolac double-layer tablets was determined by High-performance liquid chromatography(HPLC). Ultraviolet spectrophotometry(UV) method was developed for in vitro assay of drug release of tablets. Physical and chemical properties of etodolac such as equilibrium solubility and apparent oil-water partition coefficient were investigated.The solvent-melting method was selected to prepare the solid dispersion of etodolac after comparing several methods by dissolution studies. By means of the influence factors test formulation and technology factors on drug dissolution from solid dispersion were investigated. Orthogonal design test was selected to optimize the formulation. Solid dispersion of etodolac with optimal formulation was prepared under optimal technology and it's dissolution and physical state property were characterized. Dissolution studies showed that the percentage of etodolac dissolved in the first 30 min was more than 80%, differential scanning calorimetry(DSC) thermograms showed the absence of melting peaks, which indicating the presence of etodolac in amorphous form.Immediate-release tablets of etodolac were prepared by powder depressed directly technology, with calcium hydrogen phosphate(CaHPO₄.2H₂O) as excipient. Etodolac immediate-release tablet formulation was scanned by similar factor method. Prepration technologies and dissolution conditions affecting the dissolution were studied.Referring to the USP29, optimizing etodolac sustained-release tablet formulation, two critical factors, ratio of hydroxypropylmethylcellulose(HPMC) and content of lactose that were influenced the release behavior greatly, central composite design was used to optimize these two screened factors in the indices of the accumulative percentage of etodolac.The plasma concentration in six healthy dogs was tested by HPLC after a single oral administration of commercial and test formulation. The pharmacokinetics parameters were AUC_0-t 83.98±21.05μg·h/mL and 76.80±16.10μg·h/mL, C_max18.04±3.94μg/mL and 30.79 ±8.45μg/mL, t_max1.75±0.58 h and 0.75±0.96h, respectively. The relative bioavailability of etodolac double-layered tablets was 108.72±7.45%。...