Quality Evaluation And Studies On Pharmacoejnetics In Dogs Of Florfenicolgel Injectable In Situ Del

The novel drug delivery system in situ gel system which is free flowing before being used can respond to environmental stimulus and forms gel which can facilitate local drug delivery and prolong drug release compared to solutions.in situ gel can be divided into the temperature-sensitive, pH-sensitive and ion-sensitive. As a novel drug delivery system, in situ gel’s the preparation method is simple, so that in situ gel has a very good value and wide development prospects.Thermosensitive in situ gel can transform into semisolid gels only in response to temperature change from ambient to body temperature. Florfenicol, as a amphenicols, is a broad spectrum bacteriostatic antibiotic and effeetive against many Gram-positive and Gram-negative organisms. This article makes a quality assessment on florfenicol injectable in situ gel and studies pharmacokinetics of this agent in dog, the specific contents of the study as follows:1The quality evaluation of florfenicol injectable in situ gelEstablishing the method determined content of florfenicol in florfenicol injectable in situ gel by a high-performance liquid chromatography(HPLC). The condition of chromat-ographic mobile phase is acetonitrile:water(33:67),detect wavelength is223nm, the column temperature is30℃,the velocity of flow is1mL·min-1, the injection volume is20μL. The precision, recovery and stability of this method is in accordance with the analysis of methodological requirements. In the range of0.5-50.0μg·mL-1, the concentration of florfenicol and the target peak area have a good linear relationship, the target peak area (y) to the florfenicol concentration (x) can obtain the equation y=39606x+7968.9and R20.9998. According to "Chinese Pharmacopoeia" about quality requirements of preparation This article makes a quality assessment on three batches florfenicol injectable in situ gel.It is the key to the content,the pH, the viscocity, the in vitro release characteristics and the gelation temperature of florfenicol injectable in situ gel. Result,the viscosity is50mPa-s at room temperature(20℃), pH5.35±0.03, the gelation temperature35～36℃.The power equation of in vitro release characteristics is Q=0.0286t1/2-0.0908and R20.9992.2Studies on pharmacokinetics of Florfenicol injectable in situ gel in dogsThe pharmacokinetics of florfenicol injectable in situ gel and florfenicol injection was studied in twelve healthy dogs following a single intramuscular administration with a dose of50mg kg-1bodyweight and20mg kg-1body weight. Plasma samples were collected at different time points. The plasma concentrations of florfenicol were determined by a high-performance liquid chromatography(HPLC). The pharmacokinetic calculation of florf-enicol was performed using3P97. The results showed that the Plasma concentration and time relation both were best fitted with one-compartment open model following i.m. injection.The main pharmacokinetic parameter were:the team of florfenicol injectable in situ gel AUC(109.85±27.563)(μg·ml-1)·h; t,/2ke(30.31±0.44) h; Tpeak(2.62±0.32) h; Cmax (2.36±0.52)μg·mL-1; The team of florfenicol injection AUC(38.88±2.12)(μg·mL-1)h; T1/2ka (0.26±0.21) h; T1/2ke(4.69±0.31) h; Tpeak(1.17±0.34) h; Cmax(5.59±0.41)μg·mL-1.The results indicated that florfenicol injectable in situ gel injection was slow absothed and eliminated in dogs,the time that therapeutic plasma concentration and florfenicol action time in dog had prolonged the florfenicol injectable in situ gel was slow absorbed and eliminated in dogs, the time that therapeutic plasma concentration and florfenicol action time in dog had prolonged.