| The development of a dosage form improves the absorption of peptide and protein drugs via the gastrointestinal tract is one of the greatest challenges in the pharmaceutical field. Many researchers have taken up the challenge, using approaches including mucoadheive drug delivery, colon delivery, particulate drug delivery such as nanoparticles, microcapsules, liposomes, emulsions, micelles, and so on. The objective of this article is to provide the reader with outlines of novel solid lipids nanoparticle technologies for oral peptide delivery besides other two aqueous drugs. The physicochemical properties of drug-loaded nanoparticles and their in-vitro release behavior in the media as well as the in-vivo experiments are investigated.The hydrophilic peptide was choosed to study as the model drugs. luteinizing hormone-releasing hormone, LHRH-A2), was incorporated in monostearin SLN prepared by solvent diffusion method in aqueous system. To investigate the physicochemical properties of drug-loaded nanoparticle(MSLN) including size and zeta potential(charge). The drug encapsulation efficacy and in-vitro release behaviour were determined by the HPLC. Prepared the mixed-SLN with three lipids, such as monostearin stearic acid and oleic acid. Investigate the targets mentioned above.After increasing the total weight of formulation, prepared the LHRH-A2 nanoparticle powder by lyophilization, and drawn the lyophilization curve. Choosed the best lyophilizated protector from poloxamer, mannitol and lactose by determining the size of nanoparticle after diffusion of the powder.Study the the plasma level of hormone after administrating different dosage (25, 50, 100 fig/kg) LHRH-A2-MSLN to Carassiu auratusQJnaaeus) orally, with the routine of abdominal injection as control, and study the pharmacodynamics after administrated the LHRH-A2-MSLN to Hemibarbus maculatus Bleeker orally. Compared to the result by common routine of abdominal injection, the mean induced ovulation rate and fertilization rate of Hemibarbus maculatus Bleeker were evaluated.Monostearin solid lipid nanoparticle(MSLN) was quickly prepared by a novel solvent diffusion method in aqueous medium. The particle obtained under the acidic condition exhibited a single size distribution, with a volume mean diameter of 432.1 ±133.3 nm .MSLN could be separated completely by centrifuge of 4000 r ? min'1 at the condition of the acidic dispersed aqueous medium(pH1.2) as the zeta potential value of drug-loaded nanoparticles approached zero and aggregated together at this time. The recovery of MSLN was remarkablely increased. About 63.4% drug was incorporated in MSLN prepared in the acidic aqueous medium. 28.4% drug released burstly from MSLN at the first 8h, followed by a distinctly prolonged release over a monitored period of 14 d, nearly 3.4% drug was released in each day. These results indicated that some drug may adsorb on the surface of nanoparticle or precipitate on the surface of solid lipid matrix as the way of drug molecular. A majority of drug was incorporated in the solid lipid framework. The drug release behaviour was mainly effected by the erosion of lipid the manifested a prolonged release behabiour. The nanoparticle was made of mixed lipids such as monostearin, stearic acid and oleic acid had a significantly different in the physicochemical properties of size, zeta potential and drug encapsulation efficiency. Adding oleic acid in a certain degree, can increase the release rate.The LHRH-A2 nanoparticle powder was obtained through lyophilization. The lyophilization curve was drawn. After adding different type and concentration of lyophilized protectors in the nanoparticle suspension, study on the re-diffusion of nanoparticle powder. After determining the size and zeta potential of diffusing the nanoparticle powder in water, the 0.3%(w/w) poloxamer was found to be the best lyophilized protector.In the study of pharmacokinetics, the plasma concentration peak of hormone in Carassiu a?ratas(Linnaeus)was reached in 0.5 h after injection abdominally of control, and decreased rapidly subsequently. After being administrated orally the different dosage drug-loaded nanoparticle (trial teams) to fish, a significant absorbing peak were all rised in 2h. the hormone level in fish increased when the drug dosage increased, it was call "dosage relative to concentration effect". The hormone level recovered slowly in trial teams, in 24 h, it maintained in a higher level as the order of dosage. It indicated nanoparticle technology can improve the absorbing quantity of peptide after administration orally, compared to injection, it had the longer effect on fish.Hemibarbus maculatus Bleekers hardly ovulated eggs by themselves, After administrated different dosage(25, 50 Hg/kg) LHRH-A2-MSLN, the pharmacodynamic result indicated that the LHRH-A2-MSLN according the nanoparticle technology could produce a significant effect on fish after being administrated orally, when the dosage increased from 25 ng/kg to 50 [xg/kg, the induced ovulation rate increased from 26.7% to 46.5%. Compared to injection of drug solvent, the efficient rate of oral administration got to 12.3% (low dosage) and 10.7% (high dosage), respectively. After the solid mixed-lipid nanoparticle (LHRH-A2-mSLN) were administrated orally with different dosage of 25 and 50 [xg/kg, the ovulation rate were 13.3% and 40.0%,respectively. They both were lower that the same dosage LHRH-A2-MSLN. It could be relative to the significantly burst release of drug. The effect interval was delayed 2-3 h with the oral administration, compared to the injection. This result are corresponding to the result (peak level) of pharmacokinetics in Carassiu auratusQArmacxis) after administration of drug-loaded nanoparticle. |
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