應用HPLC方法測定Cloxacillin原料藥及其製劑之力價

DETERMINATION OF CLOXACILLIN PREPARATIONS BY HIGH PERFORMANCE LIQUID CHROMATOGRAPHY

本研究發展出一種高效液相層析法，可用於鑑別及測定Cloxacillin之原料藥及其製劑（包括膠囊、注射劑、糖漿）之力價，簡單、迅捷且具特異性。使用μ-Bondapak(TM) C18為層析管，以甲醇與4%醋酸（60：40）之混合液為移動相，dimethy1phthalate為內部對照標準品，於254nm波長處以紫外光偵測器測之。標準曲線（Standard Curve）之線性迴歸方程式為 Y = 0.0379 + 0.1483x，相關係數r = 0.9998（濃度範圍為0.2～3.0mg/ml）。添加不同量之cloxacillin於市售檢體（膠囊、注射劑、糖漿）中，所得之平均回收率均在99.5%以上。重覆注射同一濃度之cloxacillin標準品溶液，所測得之變異係數（C.V.）為0.13%，顯示本法再現性（Reproducibility）極高。為得知HPLC法是否可取代微生物法測定cloxacillin製劑之力價，cloxacillin各製劑同時以二種方法作配對實驗測定力價，並用pairedt test作配對比較，結果發現，於99%可信度範園（confidence level）內，原料藥、膠囊、注射劑、糖漿各同時以二種方法測定所得之力價並不具統計上之差異。亦即HPLC法可用以取代微生物法測定cloxacillin各製劑之力價。而且各製劑及其熱分解檢品以二種方法測定所得結果之線性關條亦將於本文中討論。

A reverse-phase liquid chromatographic(RP-LC) method was developed for the assay of cloxacillin in bulk drug and pharmaceutical preparations. The samples were analysed on aμ-Bondapak (C18) column with a mobile phase of methanol-4% acetic acid (60:40) at a flow-rate of 1.5 ml / min and UV absorbance detection at 254 nm. Equations were presented for linear relationships between peak area ratios of cloxacillin to dimethylphthalate (internal standard) and the cloxacillin concentration over a rante of 2-30μg / ml(r=0.9998). Standard addition recoveries were generally greater than 98% with alldosage forms. The coefficient of variation was less than 0.2%. Furthermore, cloxacillin formulations were assayed by microbiological and RP-LC methods to determine whether the RP-LC analytical method is a suitable substitute for the microbiolobical method. Paired assay results by the two analytical methods were obtained from capsule, syrup, and degradated compounds. The results indicated that the RP-LC method is a suitable substitute for the microbiological method for potency assays and stability studies of cloxacillin forumlations.