Pharmacokinetics of timolol in aqueous humor sampled by microdialysis after topical administration of thermosetting gels.

In order to develop a thermosetting gel-based formulation, the ocular pharmacokinetics of timolol was studied utilizing microdialysis sampling technique after topical administration. A linear microdialysis probe was characterized and implanted in the anterior chamber of a rabbit. Dialysate samples collected from the aqueous humor (AH) were directly injected into the HPLC system without any pre-treatment and no interference was observed in the blank sample.

Effect of iontophoresis on skin permeation of defibrase.

Aim: To investigate the effect of iontophoresis on skin permeation of defibrase.

Methods: Iontophoresis was carried out in side-by-side chambers, excised rat skin membrane (RSM) or human epidermis membrane (HEM). The effects of electrode polarity, permeation medium pH and ionic strength were evaluated.

[Diffusion behaviors of drugs in thermosensitive in situ gels].

Aim: To study the diffusion behaviors of drugs in thermosensitive in situ gels, and provide valuable information for designing such delivery systems.

Methods: A free diffusion model was used to evaluate the effects of concentration, the property of drugs, as well as the gel compositions on the diffusivity of drugs.

Results: Drug transport through the aqueous channels of the gel followed Fickian mechanism, and no significant influence on the diffusivity was observed when the drug concentration was lowered from 5% to 0.

[Cutaneous permeation kinetics and pharmacodynamics of topical lidocaine gel in rat].

Aim: To study the cutaneous permeation kinetics and pharmacodynamics of lidocaine gel.

Methods: The concentration of lidocaine in dermis following topical application in rats was determined by the cutaneous microdialysis technique and related parameters were calculated; the pharmacodynamics of the gel was evaluated by electric stimulation method with EMLA (eutectic mixture of local anesthetics) cream as a control.

Results: The peak of percutaneous absorption kinetic profile of lidocaine gel across rat skin occurred at 1.

[Enhancement of gastrointestinal absorption of chitosan-coated insulin-loaded poly (lactic-co-glycolic acid) nanoparticles].

Aim: To study chitosan-coated poly (lactic-co-glycolic acid) (PLGA) nanoparticles (NPs) on enhancing gastrointestinal absorption of insulin.

Methods: Insulin-loaded PLGA multiple emulsions were prepared by a double-emulsion method. Using chitosan as a stabilizer, chitosan-coated PLGA-NPs was prepared.

[Study on preparation and oral efficacy of insulin-loaded poly(lactic-co-glycolic acid) nanoparticles].

Aim: To investigate the possibility of poly(lactic-co-glycolic acid) as a carrier for the delivery of macromolecular.

Methods: Insulin-loaded poly (lactic-co-glycolic acid) nanoparticles (INS-PLGA-NPs) was prepared by a double-emulsion solvent evaporation method. The size distribution was examined by photo-correlation spectrometry.

[Effect of solution viscosity on polymer precorneal residence time evaluated by in vitro method].

Aim: To evaluate how solution viscosity affects the precorneal residence of five water-soluble polymers with different properties.

Methods: Captive bubble technique was used, with the consecutive change of contact angle interpreted as an indication of desorption process, to study the residence of those polymers in vitro on freshly enucleated rabbit eyes under physiological conditions.

Results: Carbopol and sodium hyaluronate (HA), which adsorbed to isolated ocular surface more than 15 min, showed the optimum precorneal retentive capabilities.

[The enhancing effect of electroporation and iontophoresis on the permeation of insulin through human skin].

Aim: To study the enhancing effect of electroporation and iontophoresis on the permeation of insulin through human cadaver skin in vitro.

Methods: Using side by side two-chamber diffusion cells, the flux of insulin achieved with iontophoresis and electrophoration were compared.

Results: The application of high-voltage pulse combined with iontophoresis resulted in higher flux transdermal permeation of insulin than either one technique alone (P < 0.

Bioadhesive polysaccharide in protein delivery system: chitosan nanoparticles improve the intestinal absorption of insulin in vivo.

There are many ongoing investigations to improve the oral bioavailability of peptide and protein formulations. Bioadhesive polysaccharide chitosan nanoparticles (CS-NPs) would seem to further enhance intestinal absorption of them. In this study, Insulin-loaded CS-NPs were prepared by ionotropic gelation of CS with tripolyphosphate anions.

Relationship between drug effects and particle size of insulin-loaded bioadhesive microspheres.

Aim: To formulate and characterize insulin-loaded adhesive microspheres (MP) and evaluate drug effects of MP with various sizes, 120, 350, and 1000 nm in diameter, in the alloxan-induced diabetic rats.

Methods: Insulin-loaded MP were formulated by an ionotropic gelation procedure. Particle size distributions were determined by photon correlation spectroscopy and optical microscopy.

Thermosetting gels with modulated gelation temperature for ophthalmic use: the rheological and gamma scintigraphic studies.

For ophthalmic drug delivery, Pluronic F127 solutions have a phase transition temperature too low for them to be instilled into the eye at room temperature. Refrigerator storage is usually required to make administration easier, whereas the potential irritation of cold to the sensitive ocular tissues may result in poor topical bioavailability. The purpose of this study is to develop a thermosetting gel with a suitable phase transition temperature by combining Pluronic analogs and to examine the influence of incorporating mucoadhesive polysaccharide, sodium hyaluronate (HA-Na), on the ocular retention of the gel.