Weijtens O, van der Sluijs F A, Schoemaker R C, Lentjes E G, Cohen A F, Romijn F P, van Meurs J C
Rotterdam Eye Hospital, The Netherlands.
Am J Ophthalmol. 1997 Mar;123(3):358-63. doi: 10.1016/s0002-9394(14)70131-x.
To study the dexamethasone level reached in human vitreous after a peribulbar injection of 5 mg of dexamethasone disodium phosphate and to assess its systemic uptake.
In a prospective study, 61 eyes of 61 patients scheduled for vitrectomy received a single peribulbar injection of 5 mg of dexamethasone disodium phosphate at varied intervals before surgery. At the start of vitrectomy, an undiluted vitreous sample was taken. In 22 patients, multiple serum samples were collected. Dexamethasone concentrations were measured by radioimmunoassay. The physiologic cortisol concentration was determined in the vitreous of 12 eyes of 12 patients who did not receive dexamethasone.
An average dexamethasone peak concentration of approximately 13 ng/ml was reached in vitreous 6 to 7 hours after peribulbar injection. In serum the average peak concentration was approximately 60 ng/ml 20 to 30 minutes after peribulbar injection. The average physiologic cortisol concentration in vitreous was 5.1 ng/ml.
After a peribulbar injection of 5 mg of dexamethasone disodium phosphate, an average intravitreal dexamethasone concentration is reached with a 75 times greater anti-inflammatory potency than physiologically present cortisol. Dexamethasone concentration in serum, however, is several times higher. Peribulbar injection is not just a local treatment but results in serum levels comparable to those achieved by a high oral dose.
研究球周注射5mg地塞米松磷酸钠后玻璃体内所达到的地塞米松水平，并评估其全身摄取情况。
在一项前瞻性研究中，61例计划接受玻璃体切除术的患者的61只眼在手术前不同时间接受了单次5mg地塞米松磷酸钠的球周注射。在玻璃体切除术开始时，采集未稀释的玻璃体样本。在22例患者中，采集了多个血清样本。通过放射免疫测定法测量地塞米松浓度。在12例未接受地塞米松的患者的12只眼中测定了生理性皮质醇浓度。
球周注射后6至7小时，玻璃体内地塞米松平均峰值浓度约为13ng/ml。血清中平均峰值浓度在球周注射后20至30分钟约为60ng/ml。玻璃体内生理性皮质醇平均浓度为5.1ng/ml。
球周注射5mg地塞米松磷酸钠后，玻璃体内地塞米松平均浓度达到，其抗炎效力比生理状态下的皮质醇高75倍。然而，血清中的地塞米松浓度要高出几倍。球周注射不仅仅是一种局部治疗，其导致的血清水平与高口服剂量所达到的水平相当。
