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The main purpose of this work was to develop a supersaturatable self-microemulsifying drug delivery system (S-SMEDDS) of carbamazepine (CBZ). S-SMEDDS of CBZ was prepared and drug precipitation behavior, dissolution rate in vitro and particle size distribution were evaluated. The relative bioavailability of S-SMEDDS formulation of CBZ was evaluated in beagle dogs compared with a commercial tablet. The results showed that the presence of a small amount of polymeric precipitation inhibitor (PVP) effectively sustained the supersaturated state by retarding precipitation kinetics. The mean particle size of S-SMEDDS formulation after dispersion was about 33.7 nm and the release rate from S-SMEDDS was significantly higher than the commercial tablet in vitro. In pharmacokinetic parameters of S-SMEDDS formulation, AUC0∼∼t and Cmax were 9.83 ±± 2.47 μμg··ml−−1··h and 4.96 ±± 1.16 μμg··ml−−1, compared to the conventional tablet which were 1.67 ±± 1.19 μμg··ml−−1··h and 0.74 ±± 0.19 μμg··ml−−1, respectively. AUC0-t of S-SMEDDS increased nearly five times compared to the market tablet with the same administration dose of 200 mg. On the other hand, AUC0--t of S-SMEDDS with a dose of 50 mg was about 85.9% compared to the commercial tablet with a dose of 200 mg. Thus, it was concluded that S-SMEDDS provide an effective approach for improving the extent of absorption of CBZ with a low surfactant level. [ABSTRACT FROM AUTHOR]

Rheological properties of poloxamer 407 (brand named Pluronic F127) were examined by changing shear rate, temperature and the recovery properties of apparent viscosity after heating for several times. The results indicated that poloxamer 407 aqueous solution showed a Newtonian behavior at a low concentration while it might be a pseudoplastic fluid when the concentration reached a certain point. The thixotropy and the sol-gel transition temperature decreased with increasing the concentration (it could be an in situ gel at body temperature when the concentration of poloxamer 407 up to 15.25%). The results that obtained from the theological data would be useful in the application of poloxamer 407 such as in situ gel preparation.

Using a simple method to determine the interaction between peptide and lipid bilayer and then deciding how to modify formulation from classic DepoFoam technology, multivesicular liposome of LXT-101 (DepoLXT-101) was prepared and characterized by in vitro evaluation. The electrostatic adsorption between peptide and lipid bilayer was observed by zeta potential and fluorescence spectrum. Anionic surfactants were added to stable the multiple emulsion and minimize the opposite effects resulted from drug. Encapsulation efficiency was determined by RP-HPLC. Morphology, particle size of DepoLXT-101 particles were characterized and their in vitro release was studied in sodium chloride solution. The DepoLXT-101 particles were prepared with good encapsulation efficiency, narrow size distribution and multivesicular construction. Over 95% of the DepoLXT-101 particles were in a size range of 5-20 microm. The in vitro assay in sodium chloride solution at 37 degrees C showed that 70%-90% of the peptide was released from particles slowly over 11 days. Multivesicular liposome sustained delivery of synthetic cationic peptides could be successfully prepared by the method.

The main purpose of this work is to prepare self-emulsifying drug delivery system (SEDDS) of a poorly water soluble drug, puerarin. Solubility of puerarin was determined in various oils and surfactants. Oleic acid and Tween 80 provided higher solubility. Addition of propylene glycol as cosurfactant improved solubility of puerarin and the spontaneity of self-emulsification. A series of mixtures comprising oleic acid, propylene glycol and Tween 80 were prepared and their self-emulsifying properties were studied. Pseudo-ternary phase diagrams were constructed to identify the efficient self-emulsification region and particle sizes of the resultant emulsions were determined using a laser diffraction sizer. The pharmacokinetic behaviors of three different SEDDS formulations (F2, F3, F4) were investigated in Beagle dogs. The bioavailability was compared using the pharmacokinetic parameters, peak plasma concentration (C(max)), time to reach peak plasma concentration (T(max)) and total area under the plasma concentration-time curve (AUC(0-t)). AUC(0-t) was significantly higher in formulation F2 group (5.201 +/- 0.511) ng x mL(-1) x h and formulation F3 group (5.174 +/- 0.498) ng x mL (-1) x h than that in formulation F4 group (3.013 +/- 0.623) ng x mL(-1) x h. Also, C(max) was significantly higher in formulation F2 group (1.524 +/- 0.125) ng x mL(-1) and formulation F3 group (1.513 +/- 0.157) ng x mL(-1) than that in formulation F4 group (0.939 +/- 0.089) ng x mL(-1). Further analysis of the data showed a statistically significant difference between F2 and F4 (P < 0.01) as well as F3 and F4 (P < 0.01) with regard to the values of AUC(0-infinity) and C(max) for three SEDDS formulations, but not between those of F2 and F3 (P > 0.05). From these studies, the SEDDS formulation containing oleic acid (17.5%), Tween 80 (34.5%) and propylene glycol (34.5%) (w/w) was selected as an optimized SEDDS formulation of puerarin. The data suggest the potential use of SEDDS to improve oral absorption of puerarin.

Aim: To evaluate the self-emulsifying ability and dissolution behavior of tretinoin in vitro and the pharmacokinetic behavior in beagle dogs., Methods: The self-emulsifying rate was evaluated by determining the intensity of scattered light at different time and the particle size of resultant emulsions after self-emulsifying were observed by optical microscope. The plasma concentrations were determined by HPLC and dissolution and pharmacokinetic behavior of self-emulsifying formulations were evaluated by comparison with commercial capsules., Results: The area under the curve (AUC) was significantly higher in the tretinoin self-emulsifying formulation group (3048.0 mg x h x L(-1)) than that in the commercial capsule group (1826.0 mg x h x L(-1)). Also, Tmax was smaller in the self-emulsifying formulation group (1.25 h) compared with market products (2 h) and the dissolved amount from self-emulsifying formulations in water at 15 min was much higher (more than 80%) than that of the market products (less than 5%)., Conclusion: The self-emulsifying drug delivery systems can increase drug dissolution in vitro and absorption in vivo significantly.