Pharmacokinetics and pharmacodynamics of desmopressin acetate in rabbits after intraocular administration / 药学学报

We compared the pharmacokinetic and pharmacodynamic profiles of desmopressin acetate after intraocular, intravenous and intragastric administration in rabbits to better understand the systemic delivery of peptide drugs through intraocular administration. Fifteen rabbits were randomly divided into three groups (intraocular administration, 7 μg·kg-1; intravenous administration, 0.7 μg·kg-1; and intragastric administration, 7 μg·kg-1). Blood samples were taken from the heart at predetermined time points after dosing and the plasma desmopressin concentration was analyzed by enzyme-linked immunosorbent assay (ELISA). Another 21 rabbits were randomly divided into three groups (intraocular administration, 7 μg·kg-1; intravenous administration, 0.7 μg·kg-1; intragastric administration, 7 μg·kg-1) for a pharmacodynamics study. Urine was collected at predetermined intervals after dosing. The pharmacokinetic parameters after intravenous administration were as follows: Cmax was 143.0 pg·mL-1; the area under the plasma concentration–time curve for desmopressin (AUC0-t) was 999.9 pg·h·mL-1. The pharmacokinetic parameters after intraocular administration were as follows: tmax was 5 min, Cmax was 125.6 pg·mL-1, AUC0-t was 873.1 pg·h·mL-1, and absolute bioavailability (F) was 8.7%. The pharmacokinetic parameters after intragastric administration were as follows: tmax was 10 min, Cmax was 104.1 pg·mL-1, AUC0-t was 451.8 pg·h·mL-1, and absolute bioavailability was 4.5%. Intraocular administration and intravenous administration of one tenth of the dosage showed a similar effect, and the urine volume remained decreased for 12 h, but urine volume increased significantly in the second collection period after intragastric administration, and there was no decrease in volume 12 h after dosing. This study demonstrates that peptide drugs such as desmopressin can be absorbed more rapidly after intraocular administration than after intragastric administration and can exert systemic therapeutic effects. In this study, the program of animal testing had been approved by the Laboratory Animal Care and Use Committee at Anhui University of Chinese Medicine.

Pharmacokinetics of Nimodipine after Intraocular Administration in Rats / 中国医学科学院学报

Objective To explore the pharmacokinetics of nimodipine in plasma of rats after intraocular administration.Methods Totally 135 SD rats were randomly divided into three groups according to drug administration routes:intraocular(io group),intravenous (iv group),and intragastric (ig group). The doses were 5.0 mg/kg for IO and IV groups and 10.0 mg/kg for IG group. The serum nimodipine level was analyzed by high performance liquid chromatography. The main pharmacokinetic parameters were calculated and compared.Results The pharmacokinetic parameters in io group were as follows:C:0.52 mg/ml;t:5.0 min;and AUC:21.10 mg/(ml·min). The main pharmacokinetic parameters in iv group were as follows:C:3.62 mg/ml;and AUC:52.58 mg/(ml·min). The main pharmacokinetic parameters in ig group were as follows:C:0.20 mg/ml;t:5.0 min;and AUC:5.98 mg/(ml·min).Conclusions Nimodipine is rapidly absorbed after io administration,and the ophthalmic formulation has a higher bioavailability than the oral solution. Therefore,the io route may help to improve the treatment effectiveness of cardiovascular diseases.