Improved Oral Pharmacokinetics of Pentoxifylline with Palm Oil and Capmul® MCM Containing Self-Nano-Emulsifying Drug Delivery System.

Pentoxifylline (PTX), an anti-hemorrhage drug used in the treatment of intermittent claudication, is extensively metabolized by the liver resulting in a reduction of the therapeutic levels within a short duration of time. Self-nano-emulsifying drug delivery system (SNEDDS) is well reported to enhance the bio-absorption of drugs by forming nano-sized globules upon contact with the biological fluids after oral administration. The present study aimed to formulate, characterize, and improve the oral bioavailability of PTX using SNEDDS. The formulated SNEDDS consisted of palm oil, Capmul® MCM, and Tween® 80 as oil, surfactant, and co-surfactant, respectively. The mixture design module under the umbrella of the design of experiments was used for the optimization of SNEDDS. The dynamic light-scattering technique was used to confirm the formation of nanoemulsion based on the globule size, in addition to the turbidity measurements. In vivo bioavailability studies were carried out on male Wistar rats. The pharmacokinetic parameters upon oral administration were calculated using the GastroPlus software. The optimized SNEDDS had a mean globule size of 165 nm with minimal turbidity in an aqueous medium. Bioavailability of PTX increased 1.5-folds (AUC = 1013.30 ng h/mL) as SNEDDS than the pure drug with an AUC of 673.10 ng h/mL. In conclusion, SNEDDS was seen to enhance the bioavailability of PTX and can be explored to effectively control the incidents of intermittent claudication.

Design and evaluation of self-nanoemulsifying drug delivery systems (SNEDDSs) for senicapoc.

Senicapoc (SEN), a potent antisickling agent, shows poor water solubility and poor oral bioavailability. To improve the solubility and cell permeation of SEN, self-nanoemulsifying drug delivery systems (SNEDDSs) were developed. Capryol PGMC®, which showed the highest solubilization capacity, was selected as the oil. The self-emulsification ability of two surfactants, viz., Cremophor-EL® and Tween® 80, was compared. Based on a solubility study and ternary phase diagrams, three optimized nanoemulsions with droplet sizes less than 200 nm were prepared. An in vitro dissolution study demonstrated the superior performance of the SNEDDS over the free drug. During in vitro lipolysis, 80% of SEN loaded in the SNEDDS remained solubilized. An in vitro cytotoxicity study using the Caco-2 cell line indicated the safety of the formulations at 1 mg/mL. The transport of SEN-SNEDDSs across Caco-2 monolayers was enhanced 115-fold (p < 0.01) compared to that of the free drug. According to these results, SNEDDS formulations could be promising tools for the oral delivery of SEN.

Synergistic interaction between exogenous and endogenous emulsifiers and its impact on in vitro digestion of lipid in crowded medium.

Control of lipid digestibility by various food components has received great attention in recent decades. However, there is limited literature on investigating the synergistic effect of exogenous emulsifiers and endogenous sodium cholate (SC) on lipid digestion in a simulated physiological crowded medium. In this work, the synergistic interaction of Tween80 and SC according to the regular solution theory, and the hydrolysis of lipid emulsions containing tricaprylin, glyceryltrioleate or soybean oil in crowding medium was studied. The results show that emulsions stabilized by a combination of Tween80 and SC showed higher digestion rate and transformation than those with Tween80 or SC. The digestion rate could be increased by polyethylene glycols (PEGn) with varying crowding degree. The denaturation temperature of the lipase was increased in macromolecular crowded medium. This work allows for better understanding of the interaction between the amphiphiles and the macromolecular crowding effect on lipase digestion in the physiological environment.

Evaluation of self-nanoemulsifying drug delivery systems using multivariate methods to optimize permeability of captopril oral films.

The present report demonstrates a quality by design approach to understand and optimize self-nanoemulsifying orodispersible films (SNEODF) of captopril for hypertension. A central composite experimental design was used to study the formulation parameters effects (primary emulsion, aqueous phase, and surfactant) on the film properties (globule size, film burst, adhesion, Young's moduli, disintegration time, tensile strength and dissolution). Principle component analysis (PCA) and principle component regression (PCR) were employed to identify and quantify the effects of formulation variables and physico-mechanical properties of the film on the drug permeability. PCA classified three distinct groups of film formulations based on their composition and properties. PCR quantified the impact of main variables, their interactions, and square effects on the drug permeability. The main effect of the aqueous phase exhibited a negative impact, while that of flux and tensile strength showed a positive impact on the permeability. Interactions of primary emulsions with disintegration time and tensile strength displayed a synergistic impact. Interactions of aqueous phase with flux, Young's moduli, and tensile strength, as well as between Young's moduli and tensile strength showed a significant positive effect on the permeability. A negative correlation of square effects of primary emulsion and flux, and a positive square effect of Young's moduli confirmed their non-linear influence on the drug permeability across porcine buccal mucosa. This research work demonstrates application of design of experiment and multivariate methods to achieve targeted product quality of captopril (SNEODF) having improved permeability and pH independent release profile.

Development and In Vivo Evaluation of Ziyuglycoside I-Loaded Self-Microemulsifying Formulation for Activity of Increasing Leukocyte.

Ziyuglycoside I (ZgI), a major effective ingredient of Sanguisorba officinalis L, has shown good activity in increasing leukocyte of myelosuppression mice. However, oral ZgI therapy has been deterred by poor bioavailability because of its low aqueous solubility and permeability. Our study was to develop ZgI-loaded self-microemulsifying drug delivery system (SMEDDS) and evaluate its intestinal absorption, and pharmacokinetic and pharmacodynamic activity for increasing leukocyte. The formulation was designed and optimized by measuring the equilibrium solubility of ZgI in different vehicles and the pseudoternary phase diagram. Further, morphology, particle size, stability, in vitro release, in situ single-pass intestinal perfusion (SPIP), in vivo activity, and in vivo pharmacokinetic (PK) of ZgI-SMEDDS were charactered or studied. Optimized formulations for in vitro dissolution were Obleique CC497, Tween-20, and Transcutol HP with a proportion of 0.25/0.45/0.30 via D-optimal mixture design. Results showed that the solubility of ZgI was enhanced up to 23.93 mg/g and its average particle size was 207.92 ± 2.13 nm. The release of ZgI had been greatly improved by the SMEDDS. In SPIP, the intestinal absorption of SMEDDS was much better than plain ZgI. In PK, we found the oral bioavailability of ZgI-SMEDDS was 6.94-fold higher absolute bioavailability (21.94 ± 4.67) % than ZgI (3.16 ± 0.89) %. The most important was that the mice WBC of ZgI-SMEDDS group was significantly higher than that of the ZgI group. Our study suggested that SMEDDS could increase the solubility of ZgI, which was beneficial to improve oral bioavailability and enhance biological activity.

Lipid Nanoemulsions of Rebamipide: Formulation, Characterization, and In Vivo Evaluation of Pharmacokinetic and Pharmacodynamic Effects.

Rebamipide has low oral bioavailability (10%) due to its low solubility and permeability. Lipid nanoemulsions (LNEs) were prepared in order to improve its oral bioavailability. Rebamipide-loaded lipid nanoemulsions were formulated by hot homogenization and ultrasonication method. Olive oil and egg lecithin in various concentrations as emulsifier were used in the preparation of LNEs. The lipid nanoemulsions were evaluated for various parameters. The globule size, polydispersity index (PDI), and zeta potential (ZP) of the formulations ranged from 230.3 ± 3.88 to 279.8 ± 5.76 nm, 0.204 ± 0.008 to 0.246 ± 0.029, and - 27.7 ± 2.05 to - 31.0 ± 1.87 mV, respectively. Entrapment efficiency and assay values ranged from 99.90 ± 0.006 to 99.92 ± 0.002% and 99.3 ± 0.808 to 99.6 ± 0.360, respectively. Physical stability test results revealed that the optimized LNEs were stable for 2 months at both room (25°C) and refrigerated temperature (4°C). The optimized LNE showed 4.32-fold improvement in the oral bioavailability in comparison to a marketed tablet suspension. In vivo anti ulcer activity of rebamipide LNE was studied by testing the prophylactic effect in preventing the mucosal damage in stomach region. The mucosa of stomach in animals was damaged by per oral administration of 80% alcohol. Maximum prophylactic antiulcer activity was observed by per oral delivery of rebamipide as LNE. Our results indicated that LNEs were a promising approach for the oral delivery of rebamipide for systemic effects along with local effects in protecting gastric region, which gets damaged during peptic ulcers.

Evaluation of a self-nanoemulsifying docetaxel delivery system.

A self-nanoemulsifying drug delivery system (SNEDDS) was developed as a novel route to enhance the efficacy of docetaxel lipophilic drug. SNEDDS comprised ethyl oleate, Tween 80 and poly(ethylene glycol) 600, as oil, surfactant and co-surfactant, and formed stabilized monodispersed oil nanodroplets upon dilution in water. SNEDDS represented encapsulation efficiency and loading capacity of 21.4 and 52.7%, respectively. The docetaxel release profile from the drug-loaded SNEDDS was recorded, its effectiveness against MCF-7 cell line was investigated, and an IC50 value of 0.98 ± 0.05 µg mL-1 was attained. The drug-loaded SNEDDS was administrated in rats, and the pharmacokinetic parameters of maximum concentration of 22.2 ± 0.8 µg mL-1, time to attain this maximum concentration of 230 min, and area under the curve of 1.71 ± 0.18 µg min mL-1 were obtained. The developed SNEDDS formulation can be represented as an alternative to docetaxel administration.

Mucus permeating self-emulsifying drug delivery systems (SEDDS): About the impact of mucolytic enzymes.

This study aimed to improve the mucus permeating properties of self-emulsifying drug delivery systems (SEDDS) by anchoring lipidized bromelain, papain and trypsin using palmitoyl chloride. SEDDS containing enzyme-palmitate conjugates were characterized regarding droplet size and zeta potential. Their mucus permeating properties were evaluated by Transwell diffusion and rotating tube method using fluorescein diacetate (FDA) as marker. Degree of substitution of modified enzymes was 35.3%, 47.8% and 38.5% for bromelain-palmitate, papain-palmitate and trypsin-palmitate, respectively. SEDDS as control and SEDDS containing enzyme-palmitate conjugates displayed a droplet size less than 50nm and 180-312nm as well as a zeta potential of -3 to -4 and -4 to -5mV, respectively. The highest percentage of permeation was achieved by introducing 5% papain-palmitate into SEDDS. It could enhance the mucus permeation of SEDDS in porcine intestinal mucus 4.6-fold and 2-fold as evaluated by Transwell diffusion and rotating tube method, respectively. It is concluded that mucus permeation of SEDDS can be strongly improved by incorporation of enzyme-palmitate conjugates.

Solid Dispersion of Curcumin as Polymeric Films for Bioenhancement and Improved Therapy of Rheumatoid Arthritis.

PURPOSE: The aim of our study was development of advanced third generation Curcumin self microemulsifying composition solid dispersion (Cur SMEC-SD) with high drug loading, improved stability, rapid in-vitro dissolution and enhanced bioavailability for improved therapy of rheumatoid arthritis. METHOD: The Cur SMEC-SD comprising polymers (KollidonVA64[KVA], Eudragits, HPMC and Soluplus) and self microemulsifying composition of surfactant:co-surfactant:oil were coated onto rapidly disintegrating inert tablet core. SDs evaluated for stability, in-vitro release and bioenhancement. RESULTS: Cur SMEC-SDs exhibited high Cur loading of 45% w/w and microemulsion formation with globule size (~100 nm) irrespective of polymers. Among the polymers, SD with KVA revealed exceptionally low contact angle (7°C) and rapid in-vitro release (t50%-6.45 min). No crystallization was evident as confirmed by SEM, DSC and XRD and is attributed to SMEC aided solubilization/amorphisation, and interaction of KVA with Cur seen in the FTIR spectra. Stability was confirmed as per ICH guidelines. Remarkable bioenhancement with Cur SMEC-SD was confirmed by the > four fold and a two fold compared to Cur and Cur-SD without SMEC respectively. High efficacy ~ 80% compared to Indomethacin, seen with rheumatoid arthritis (RA) induced rats coupled with no adverse toxicity. CONCLUSION: The advanced third generation Cur SMEC-SD presents a practical technological advancement and suggests Cur SMEC-SD as promising alternative for RA therapy.

Rosmarinus officinalis L. extract and some of its active ingredients as potential emulsion stabilizers: a new approach to the formation of multiple (W/O/W) emulsion.

Nowadays, novel topical formulations loaded with natural functional actives are under intense investigations. Therefore, the aim of our study was to evaluate how the rosemary extract and some of its active ingredients [rosmarinic acid (RA), ursolic acid (UA) and oleanolic acid (OA)] affect technological characteristics of multiple emulsion. Formulation has been prepared by adding investigated solutions (10%) in water/oil/water (W/O/W) multiple emulsion consisting of different lipophilic phases: olive oil and liquid paraffin, with 0.5% emulsifying agent (complex of sodium polyacrylate and polysorbate 20) under constant stirring with mechanical stirrer at room temperature. The emulsion parameters were evaluated using centrifugation test, freeze-thaw cycle test, microscopical and texture analyses. Rosemary's triterpenic saponins UA and OA showed the highest emulsion stabilizing properties: they decreased CI from 3.26% to 10.23% (p < 0.05). According to obtained interfacial tension data, the effect of rosemary active ingredients is not surfactant-like. Even though emulsifier itself at low concentration intends to form directly the multiple emulsion, the obtained results indicate that rosemary extract containing active ingredients does not only serve as functional cosmetic agent due to a number of biological activities, but also offer potential advantages as a stabilizer and an enhancer of W/O/W emulsions formation for dermopharmaceutical and cosmetic preparations.

Submicron complex lipid carriers for curcumin delivery to intestinal epithelial cells: Effect of different emulsifiers on bioaccessibility and cell uptake.

Submicrometric lipid-based carriers were developed to encapsulate curcumin and deliver it to intestinal epithelial cells. A lipid matrix comprising monoolein, sunflower oil and water at weight ratio 1:1:1 was selected, upon screening of different combinations of amphiphilic molecules, vegetable oils and water, because of its high encapsulations efficiency of curcumin, retained over time and relatively lower content of amphiphilic molecules. Upon dispersion in aqueous phase, the carriers were stabilized by: (a) whey protein isolates (WPI), alone and (b) in combination with modified starch (WPI-MS), or by (c) polysorbate 20 (T20). Whereas T20-stabilized systems exhibited extremely fine particles (120 nm), WPI and WPI-MS stabilized carriers were characterized by a significantly larger mean particle size (270 nm). The thicker macromolecular layer of WPI and WPI-MS enabled better (a) physical stability, (b) controlled shell degradation during simulated digestion, and (c) curcumin bioaccessibility targeted at the intestinal digestion phase than T20-systems. However, uptake studies in HT29 cell lines, simulating intestinal epithelial cells, showed that WPI and WPI-MS carriers exhibited after 24h a lower relative uptake than T20-stabilized systems (about 60% and 80%, respectively), as a consequence of smaller size and higher cell adherence of T20 carriers to the cell membrane.

Preparation and performance evaluation of emulsomes as a drug delivery system for silybin.

We developed silybin (SIL) emulsomes and evaluated their physicochemical properties and the in vivo pharmacokinetics of SIL delivered by emulsomes in rats. SIL emulsomes were prepared using the thin film dispersion method. SIL emulsomes were evaluated for their entrapment efficiency, particle size, zeta potential, morphology, in vitro release, and in vivo drug delivery in rats. The entrapment efficiency was above 80 %. The average particle size and zeta potential were 364.1 ± 20 nm and -34 ± 8 mV, respectively. Morphological analysis revealed that the SIL emulsomes were spherical in shape. Compared to an SIL solution, emulsomes produced sustained release of SIL for up to 48 h after an initial burst release in vitro. The pharmacokinetics of SIL emulsomes in rats were evaluated after intravenous injection, and the results were compared with those obtained for the control SIL solution. Following SIL delivery by emulsomes, the area under the curve was 2.2-fold higher and the mean residence time was 2.5-fold higher than the corresponding values recorded using SIL solution. Hence, emulsomes might represent a promising system for improving the bioavailability of lipophilic drugs. Moreover, emulsomes produce sustained drug release, which is advantageous in the clinical setting.

Preparation and evaluation of SEDDS of simvastatin by in vivo, in vitro and ex vivo technique.

The objective of this work was to formulate a Self Emulsifying Drug Delivery System (SEDDS) of simvastatin, a poorly soluble drug and to evaluate by in vivo, in vitro and ex vivo techniques. Oils and surfactants were screened out depending upon their solubilizing capacity. Among all of the solvents, Capryol 90 showed good solubilizing capacity. It dissolved 105 mg/ml of simvastatin. Tween-80 also showed good solubilizing capacity which was 117 mg/ml. The two excipients were used to prepare simvastatin SEDDS. Formulations were initially checked for the color, clarity and sedimentation. The SEDDS formulations were transparent and clear. Formulation F2 containing 7:3 (m/m) mixture of Capryol 90/Tween-80 produced smallest micro-emulsion with particles size of 0.074 µm and drug release was higher than other formulation (102% within 20 min). Ex vivo study of the SEDDS formulation was evaluated using guinea pig intestinal sac. Drug diffused from F2 formulation was significantly higher than pure drug (p < 0.001). In vivo study of SEDDS was performed in albino mice using plasma cholesterol level as a pharmacodynamic marker parameter. The test formulation (F2) appeared remarkable reduction in plasma cholesterol level, after oral administration which showed that SEDDS may be an effective technique for the oral administration of simvastatin.

Design and optimization of self-microemulsifying drug delivery system (SMEDDS) of felodipine for chronotherapeutic application

The objective of this research work was to design, develop and optimize the self micro-emulsifying drug delivery system (SMEDDS) of Felodipine (FL) filled in hard gelatine capsule coated with polymer in order to achieve rapid drug release after a desired time lag in the management of hypertension. Microemulsion is composed of a FL, Lauroglycol FCC, Transcutol P and Cremophor EL. The optimum surfactant to co-surfactant ratio was found to be 2:1. The resultant microemulsions have a particle size in the range of 65-85 nm and zeta potential value of -13.71 mV. FL release was adequately adjusted by using pH independent polymer i.e. ethyl cellulose along with dibutyl phthalate as plasticizer. Influence of formulation variables like viscosity of polymer, type of plasticizer and percent coating weight gain was investigated to characterize the time lag. The developed formulation of FL SMEDDS capsules coated with ethyl cellulose showed time lag of 5-7 h which is desirable for chronotherapeutic application.

O objetivo desse trabalho de pesquisa foi planejar, desenvolver e otimizar sistema de liberação de fármaco auto-microemulsificante(SMEDDS) de felodipino (FL) em cápsulas de gelatina dura revestidas com polímero, a fim de obter liberação rápida após tempo desejado no manejo da hipertensão. A microemulsão é composta de FL, lauroglilcol FCC, Transcutol P e Cremophor EL. A proporção ótima de tensoativo e de co-tensoativo foi de 2:1. As microemulsões resultantes têm tamanho de partícula na faixa de 65-85 nm com potencial zeta de -13,71 mV. A liberação de FL foi ajustada adequadamente, utilizando-se polímero independente de pH, como etilcelulose com ftalato de dibutila como plastificante. A influência das variáveis da formulação, como viscosidade do polímero, tipo de plastificante e ganho percentual de peso do revestimento foi investigada para caracterizar o intervalo de tempo de liberação. A formulação de cápsulas de FL SMEDDS revestidas com etilcelulose mostrou intervalo de tempo de liberação de 5 a 7 horas, o que é desejável para uma aplicação cronoterapêutica.

Self-nanoemulsifying drug delivery system (SNEDDS) for oral delivery of Zedoary essential oil: formulation and bioavailability studies.

The aim of the present study was to develop a self-nanoemulsifying drug delivery system (SNEDDS) for the oral delivery of Zedoary turmeric oil (ZTO), an essential oil extracted from the dry rhizome of Curcuma zedoaria. Pseudo-ternary phase diagrams were constructed to identify the efficient self-emulsification regions. ZTO could serve as a partial oil phase with the aid of the second oil phase to enhance drug loading. Increasing the surfactant concentration reduced the droplet size but increased the emulsification time, while the reverse effect was observed by increasing the co-surfactant concentration. Based on the emulsification time, droplet size and zeta potential after dispersion into aqueous phase, an optimized formulation consisting of ZTO, ethyl oleate, Tween 80, transcutol P (30.8:7.7:40.5:21, w/w) and loaded with 30% drug was prepared. Upon mixing with water, the formulation was rapidly dispersed into fine droplets with a mean size of 68.3+/-1.6 nm and xi-potential of -41.2+/-1.3 mV. The active components remained stable in the optimized SNEDDS stored at 25 degrees C for at least 12 months. Following oral administration of ZTO-SNEDDS in rats, both AUC and C(max) of germacrone (GM), a representative bioactive marker of ZTO, increased by 1.7-fold and 2.5-fold respectively compared with the unformulated ZTO.

Study of the preparation of sustained-release microspheres containing zedoary turmeric oil by the emulsion-solvent-diffusion method and evaluation of the self-emulsification and bioavailability of the oil.

The purpose of this study was to design a sustained-release formulation of an oily drug. The sustained-release microspheres with self-emulsifying capability containing zedoary turmeric oil (ZTO) were prepared by the quasi-emulsion-solvent-diffusion method. The micromeritic properties, the efficiency of emulsification and the drug-release behavior of the resultant microspheres were investigated. The bioavailability of the microspheres was compared with conventional ZTO self-emulsifying formulations for oral administration using 12 healthy rabbits. An HPLC method was employed to determine the concentration of germacrone in plasma, which was used as an index of ZTO. Spherical and compacted microspheres with average diameters of 100-600 microm have been prepared, and their release behavior in distilled water containing 1.2% (w/v) of polysorbate-80 can be controlled by the ratio of polymer/Areosil200 in the microspheres. The resultant emulsions with mean droplet sizes of 200-500 nm are produced when the microspheres are immersed in phosphate buffer (pH 6.8) under gentle agitation. The stability and the droplet size of the resultant emulsions are also affected by the polymer/Areosil200 ratio in the formulation, while the amount of talc has a marked effect on the self-emulsifying rate. The plasma concentration-time profiles with improved sustained-release characteristics were achieved after oral administration of the microspheres with a bioavailability of 135.6% with respect to the conventional self-emulsifying formulation (a good strategy for improving the bioavailability of an oily drug). In conclusion, the sustained-release microspheres with self-emulsifying capability containing ZTO have an improved oral bioavailability. Our study offers an alternative method for designing sustained-release preparations of oily drugs.

Self-microemulsifying drug delivery systems (SMEDDS) for improving in vitro dissolution and oral absorption of Pueraria lobata isoflavone.

The aim of our investigation was to develop and characterize self-microemulsifying drug delivery systems (SMEDDS) of Pueraria lobata isoflavone to improve its in vitro dissolution and oral absorption in beagle dogs. SMEDDS consisted of oil (ethyl oleate), a surfactant (Tween 80), and a cosurfactant (Transcutol P). In all the SMEDDS, the level of Pueraria lobata isoflavone was fixed at 20% w/w of the vehicle. The in vitro self-microemulsification properties and droplet size analysis of SMEDDS were studied following their addition to water under mild agitation. A pseudoternary phase diagram was constructed identifying the efficient self-microemulsification region. From these investigations, an optimized formulation was selected and its dissolution and bioavailability were compared with a tablet formulation in beagle dogs. The in vitro dissolution rate of puerarin from SMEDDS was more than threefold faster than that from Yufengningxin tablets (Pueraria lobata isoflavone tablets). A 2.5-fold increase in the relative bioavailability was observed for the SMEDDS compared with Yufengningxin tablets. The absolute bioavailability of the SMEDDS was 82.32 +/- 15.51%, which was significantly improved compared with that of Yufengningxin tablets. These results demonstrate the potential of SMEDDS as an efficient way of improving the oral absorption of Pueraria lobata isoflavone.

A novel formulation design about water-insoluble oily drug: preparation of zedoary turmeric oil microspheres with self-emulsifying ability and evaluation in rabbits.

To enhance in vivo absorption of zedoary turmeric oil (ZTO) and develop new formulations of a water-insoluble oily drug, novel ZTO microspheres with self-emulsifying ability, called self-emulsifying microspheres here, were prepared in a liquid system by the quasi-emulsion solvent diffusion method. The microspheres containing hydroxypropyl methylcellulose acetate succinate (HPMCAS-LG), Talc and Aerosil 200 formed the stable surfactant-free emulsion when exposed to the pH 6.8 phosphate buffer, and were significantly different from the conventional self-emulsifying systems (SES), defined as isotropic mixtures of oil, surfactant and drug. Micromeritic properties, the efficiency of emulsification and the drug-release rate of the resultant microspheres were investigated. The bioavailability of the microspheres to the conventional self-emulsifying formulation for oral administration was evaluated in 12 healthy rabbits. A HPLC method was employed to determine the plasma concentration of Germacrone, an indexical component found in ZTO. The release rates of ZTO and Germacrone from the microspheres were enhanced significantly with increasing amounts of dispersing agents, and the efficiency of self-emulsification greatly depended on the HPMCAS-LG/Aerosil 200 ratio. The emulsion droplets released from the microspheres were much smaller than that of the conventional SES. The microsphere bioavailability (F) to the conventional SES for oral administration was 157.7%. Our method greatly improved the bioavailability of the water-insoluble oily drug from the self-emulsifying microspheres over the conventional SES and it is useful for the oily drug to form solid preparations.

The effects of emulsifying agents on disposition of lipid-soluble drugs included in fat emulsion.

The uses for drug delivery systems of two soybean oil fat emulsions prepared with an emulsifying agent, phosphatidyl choline (PC) or Pluronic F-127 (PLU), were examined comparatively in vivo and in vitro. In the presence of lipoprotein lipase (LPL) in vitro, the mean particle size of the PLU emulsion changed less than that of the PC emulsion. The production of non-esterified fatty acid (NEFA) from the PLU emulsion in the presence of LPL was smaller than that from the PC emulsion. These in vitro results indicate that the PLU emulsion is more stable than the PC emulsion. Plasma NEFA concentration following intravenous administration of the emulsions decreased with time for the PC emulsion, but was kept lower and constant for the PLU emulsion, supporting the in vitro stability data. The order of plasma cyclosporine A (CsA) concentration following intravenous administration in the above two emulsions and the mixed solution of polyethylene glycol 400 (PEG) and dimethylamide (DMA) in rats was PLU emulsion>PC emulsion>PEG/DMA solution. The plasma concentration was maintained higher and tissue distribution lower for the PLU emulsion than for other formulations. The uptake of oil violet (OV) into the rat parenchymal cells from the PLU emulsion was approximately half that from the PC emulsion, but the uptake into the Kupffer cells was almost equal in both emulsions. In conclusion, these emulsifying agents can control plasma elimination and tissue distribution of lipophilic drugs included in the emulsion. The use of the emulsion formulation makes it possible to avoid side effects through the reduction of drug uptake into non-targeted tissues.