OBJECTIVE:To establish a HPLC method for determining the content of Meropenem and to observe the stability of Meropenem in mixing with 5%GS,GNS and NS.METHODS:The conditions of HPLC were:column,Nova-Pak C18;mobile phase,acetonitrile-0.05mol KH2PO4(4∶96);flow rate,1.0ml/min;detection wavelength,300nm.After Meropenem mixing with 5%GS,GNS and NS,the changes of external apperance were observed in room temperature,the content was detected with HPLC and the pH and insoluble particles were determined.RESULTS:The calibration curve was in good linearity in the range of 12.5～250?g/ml(r=0.9 999)and the recovery was 99.7% with RSD=1.1%.CONCLUSION:This detection method is effective,rapid and accurate.Meropenem is stable in infusion fluids for 4 hr.

Objective To explore the relationship between the osteonecrotic volume (lesion size), angle and the index of necrotic extent on the femoral head. Methods Fifty-one hips in 39 patients with non-traumatic avascular osteonecrosis on the femoral head were divided into 12 equal segments from the head to the neck junction (a turning point of the spherical curve of the head) with whole hip displacement, each with 30 degrees on a coronal plane of weight-bearing surface. The osteonecrotic angle of the arc of each necrotic segment from the center of the femoral head was measured at the point of one- to 12-o'clock on imaging of two dimensional reconstruction of computerized tomography (CT) scans and anteroposterior and lateral radiographs. Necrotic volume on each segment of the femoral head was calculated with fluid displacement method. The index of osteonecrotic extent on the femoral head was calculated using direct anatomical measurements. Results Osteoneerotic volume on the femoral head at the point of 12- to one-o'clock on coronal plane was (74. 5 ± 7.4)% of the sphere equivalent of the whole femoral head, which was positively correlated to its necrotic angle [ (41.9±8. 3) degrees] at the point of one-o'clock on the plane, with a coefficient of correlation of 0. 843, and that at the point of one- to two-o'clock on the plane was (73.7 ±0. 4) %, which was positively correlated to its necrotic angle [ (41.9 ± 1.8) degrees] at the point of two-o'clock, with a coefficient of correlation of 0. 543. Osteonecrotic volume on the point of 11- to 12-o'cleck was (83.6±8.6)%, and the necrotic angle at the point of 12-o'clock was (44. 9±3.9) degrees, which were positively correlated each other, with a coefficient of correlation of 0. 701 (P <0. 01 ). Osteonecrotic volume on the femoral head was positively correlated to its necrotic angle , modified index of necrotic extent, index of necrotic extent and Kerboul conjugated necrotic angle, with coefficients of correlation of 0. 798, 0. 701, 0. 377 and 0. 398 ( P < 0. 01 ), respectively, at the point of one o' clock. Conclusions Measurements of osteonecrotic volume was positively correlated to the index of necrotic extent and necrotic angle on the femoral head, respectively. Necrotic angle on the plane at 30-degree of the trochanter on the femoral head can well reflect its necrotic volume.