Research progress of in-situ gelling ophthalmic drug delivery system

Blindness and vision impairment are the most devastating global health problems resulting in a substantial economic and social burden.Delivery of drug to particular parts of the anterior or posterior segment has been a major challenge due to various protective barriers and elimination mechanisms associated with the unique anatomical and physiological nature of the ocular system.Drug administration to the eye by conventional delivery systems results in poor ocular bioavailability(<5%).The designing of a novel approach for a safe,simple,and effective ocular drug delivery is a major concern and requires innovative strategies to combat the problem.Over the past decades,several novel approaches involving different strategies have been developed to improve the ocular delivery system.Among these,the ophthalmic in-situ gel has attained a great attention over the past few years.This review discussed and summarized the recent and the promising research progress of in-situ gelling in ocular drug delivery system.

Influence of puerarin,paeoniflorin,and menthol on structure and barrier function of tight junctions in MDCK and MDCK-MDR1 Cells

Objective:In this study,the influence of puerarin,paeoniflorin,and menthol on the structure and barrier function of tight junctions(TJs)in MadineDarby canine kidney epithelial(MDCK)and MDCK-multi-drug resistance 1(MDR1)cells was evaluated to determine the mechanisms by which the drugs cross the bloodebrain barrier(BBB).Method:Cells were treated with puerarin,paeoniflorin,and menthol followed by immunohistochemical staining with occludin,claudin-1,and F-actin.The cells were then observed using laser-scanning confocal microscopy.Average optical density(AOD)of the immunofluorescence images of the proteins were analyzed using ImageJ software while Transepithelial electrical resistance(TEER)was measured using an epithelial voltohmmeter.Results:Confocal microscopy revealed that puerarin-and paeoniflorin-treated tight junction proteins were conspicuous while menthol suppressed their expression.Correspondingly,AOD values of cells treated with puerarin or paeoniflorin,or both showed no difference compared to the control group(P>.05)while the menthol group value was downregulated.In 3 h,TEER of cells not treated with menthol were similar to the control group,while treatment with menthol significantly decreased TEER value(P<.05).In addition,application of menthol decreased TEER in MDCK cells earlier than in MDCK-MDR1 cells.Conclusion:Menthol but not puerarin and paeoniflorin may enhance paracellular transport and improve drug penetration of the BBB by disrupting the structure and,thereby,weakening the barrier function of TJs.

Anti-arthritic effects of microneedling with bee venom gel

Objective:To combine with transdermal drug delivery using microneedle to simulate the bee venom therapy to evaluate the permeation of bee venom gel.Methods:In this study,the sodium urate and LPS were used on rats and mice to construct the model.Bee venom gelemicroneedle combination effect on the model is to determine the role of microneedle gel permeation by observing inflammation factors.Results:Compared with the model group,the bee venom gelemicroneedle combination group can reduce the level of serum nitric oxide of the acute gouty inflammation model caused by sodium urate,and on LPS induced mouse model of acute inflammation effect and the micro.Conclusions:Bee venom can significantly suppress the occurrence of gouty arthritis inflammation in rats and mice LPS inflammatory reaction.Choose the 750 mm microneedle with 10N force on skin about 3 minutes,bee venom can play the optimal role,and the anti-inflammatory effect is obvious.Microneedles can promote the percutaneous absorption of the active macromolecules bee venom gel.

Stability of Xuesaitong capsules in gastrointestinal lavage fluid

Objective:To obtain a formulation with high bioavailability through evaluation of the stability of three types of Xuesaitong capsules in the stomachs and intestines of rats.We compared the stability of the Panax notoginsenoside R1 as well as the ginsenosides Rg1,Rb1,Re,and Rd in different formulations.Methods:Artificial stomach fluid(ASF)and artificial intestinal fluid(AIF)were prepared.Stability of three types of Xuesaitong capsules was examined for 4 h in stomachs and 24 h in intestines.Samples were analyzed at different times by high-performance liquid chromatography.Percent content of NGR1,GRg1,GRb1,GRe,and GRd at different times was calculated.Results:Hard capsules incubated in ASF disintegrated within 2e3 min,whereas soft capsules disintegrated within 7e8 min.Components in hard capsules were dissolved rapidly in water,with content of each compound reaching 90%in 5 min,and degradation of each compound reaching 30e50%after incubation for 240 min.Dissolution and degradation of each component in soft capsules with a water-soluble base tended to balance at 30 e90 min.Contents in soft capsules with a lipid-soluble base showed slow dissolution after ASF incubation for 120 min.Five saponins in identical types of capsules incubated in ASF had similar stability curves.Contents of hard capsules and soft capsules with a watersoluble base degraded rapidly within 30 min and reached a plateau when Xuesaitong capsules were incubated in AIF.

Identification and molecular cloning of novel antimicrobial peptides from skin secretions of the Chinese bamboo leaf odorous frog (Odorrana versabilis) and the North American pickerel frog (Rana palustris)

Objective:Amphibian skin secretions are an abundant source of bioactive peptides,some of which could be developed as candidate drugs.Among these natural peptides,cytolytic peptides have attracted the most attention given that they might replace conventional antibiotics and help deal with the problem of microbial resistance.This study discovered two bioactive peptides,Brevinin-1-PLr and Nigrocin-2-OV,from two species frogs,the Chinese bamboo leaf odorous frog (Odorrana versabilis) and the North American pickerel frog (Rana palustris),respectively.Their antimicrobial,anticancer and hemolytic activities were also investigated.Methods:cDNA sequences encoding peptides were cloned from cDNA libraries constructed from the lyophilized secretions of the Chinese bamboo leaf odorous frog and the North American pickerel frog.By reversed-phase HPLC and MS/MS fragmentation sequencing,the encoded novel peptides,named Nigrocin-2-OV and Brevinin-1-PLr,were identified in skin secretions and their structures were confirmed.Replicates of both peptides were produced through solid phase peptide synthesis.Their antimicrobial and anticancer activity was studied against three types of microorganisms (Staphylococcus aureus,Candida albicans,and Escherichia coli) and five cancer cell lines (NCI-H157,PC-3,MDA-MB-435s,MCF-7,and U251MG).Their hemolytic activity was investigated using whole horse blood.Results:In this research,cDNA sequences encoding two novel 24-mer peptides were cloned from cDNA libraries constructed from the lyophilized skin secretions of the Chinese bamboo leaf odorous frog and the North American pickerel frog.Both of the peptides had the strongest inhibitory effect against C.albicans,and IC50 values against five cancer cell lines were all under 6 μM.Conclusions:Nigrocin-2-OV and Brevinin-1-PLr had the strong ability to inhibit the proliferation of studied microorganisms and tumor cell lines,with slight hemolytic activity.Compared with Brevinin-1-PLr,Nigrocin-2-OV exhibited higher antimicrobial and anticancer activity but slightly higher hemolytic activity.