Self-microemulsifying drug delivery system (SMEDDS) of vinpocetine: formulation development and in vivo assessment

A new self-microemulsifying drug delivery system (SMEDDS) has been developed to increase the solubility, dissolution rate and oral bioavailability of vinpocetine (VIP), a poor water-soluble drug. The formulations of VIP-SMEDDS were optimized by solubility assay, compatibility tests, and pseudo-ternary phase diagrams analysis. The optimal ratio in the formulation of SMEDDS was found to be Labrafac : oleic acid : Cremophor EL : Transcutol P=40 : 10 : 40 : 10 (w/w). The average particle diameter of VIP was less than 50 nm. In vitro dissolution study indicated that the dialysis method in reverse was better than the ultrafiltration method and the dialysis method in simulating the drug in vivo environment. Comparing with VIP crude drug power and commercial tablets, (-)VIP-SMEDDS caused a 3.4- and 2.9-fold increase in the percent of accumulated dissolution at 3 h. Further study on the absorption property of VIP-SMEDDS employing in situ intestine of rats demonstrated that VIP in SMEDDS could be well-absorbed in general intestinal tract without specific absorption sites. In addition, the developed SMEDDS formulations significantly improved the oral bioavailability of VIP in rats. Relative bioavailability of (-)VIP-SMEDDS and (+)VIP-SMEDDS increased by 1.85- and 1.91-fold, respectively, in relative of VIP crude powder suspension. The mechanisms of enhanced bioavailability of VIP might contribute to the improved release, enhanced lymphatic transport, and increased intestinal permeability of the drug.     

Preparation and evaluation of self-microemulsifying drug delivery system of oridonin

The objective of this study was to develop self-microemulsifying drug delivery system (SMEDDS) to enhance the oral bioavailability of the poorly water-soluble drug, oridonin. The influence of the oil, surfactant and co-surfactant types on the drug solubility and their ratios on forming efficient and stable SMEDDS were investigated in detail. The SMEDDS were characterized by morphological observation, droplet size and zeta-potential determination, cloud point measurement and in vitro release study. The optimum formulation consisted of 30% mixture of Maisine 35-1 and Labrafac CC (1:1), 46.7% Cremopher EL, and 23.3% Transcutol P. Invitro release test showed a complete release of oridonin from SMEDDS in an approximately 12h. The absorption of oridonin from SMEDDS showed a 2.2-fold increase in relative bioavailability compared with that of the suspension. Our studies demonstrated the promising use of SMEDDS for the delivery of oridonin by the oral route.     

Curcumin-loaded lipid nanocarrier for improving bioavailability,stability and cytotoxicity against malignant glioma cells

Objective: In the present study, Curcumin (CU)-loaded nanocarrier (NC) such as nanoemulsion (NE) was developed with the objective of increasing its cytotoxicity and bioavailability through lymphatic transport by enhancing its solubility and intestinal permeability.

Materials and methods: Based on the area obtained in pseudoternary phase diagram, various % combination of Labrafac Lipophile WL 1349, Solutol HS 15, Transcutol HP and distilled water were selected. Formulations which passed physical stability studies were selected for further studies such as globule size, zeta potential, in vitro release, ex vivo permeation, in vitro lipolysis studies, bioavailability studies and cytotoxicity against glioblastoma cells (U-87).

Result and discussion: The optimized NC (NE-SB1) had small average globule diameter of 67?±?6 nm with zeta potential of ?37?±?2.5?mv which indicated long-term dispersion stability. During in vitro lipolysis study, the digestion rate of medium chain triglycerides increased with decreased globule diameter. Statistically significant difference was found in AUC_0?inf of NC formulation (p?<?0.05) compared to CU suspension. The relative bioavailability of NC was found 11.88?±?0.47 with respect to CU suspension. During cytotoxicity studies, IC₅₀ of CU solution on U87 cells was found 24.23?µM, while for the NE- SB1 it was 16.41?µM. The optimized formulation was found to be stable during 6 months of accelerated stability.

Conclusion: The overall results revealed that the CU-loaded NC is a very effective approach for enhancing the oral absorption of poorly water-soluble drug CU and have great potential for future clinical application.     

Solubilized formulation of olmesartan medoxomil for enhancing oral bioavailability

Olmesartan medoxomil (OLM) is an antihypertensive angiotensin II receptor blocker. OLM has a low bioavailability (BA), approximately 26% in humans, due to its low water solubility and efflux by drug resistance pumps in the gastrointestinal tract. Self-microemulsifying drug delivery system (SMEDDS), which is easily emulsified in aqueous media under gentle agitation and digestive motility, was formulated to increase the oral BA of OLM. Among the surfactants and oils studied, Capryol 90, Tween 20, and Tetraglycol were chosen and combined at a volume ratio of 1:6:3 on the basis of equilibrium solubility and phase diagram experiments. The mean droplet size of SMEDDS was 15 nm. In an oral absorption study in rats, SMEDDS formulation brought faster absorption compared to suspension, showing a T _max value of 0.2 hr. The C _max and AUC values of SMEDDS formulation were significantly higher than those of suspension, revealing a relative BA of about 170%. Our study demonstrated the potential usefulness of SMEDDS for the oral delivery of poorly absorbable compounds, including OLM.     

Development and evaluation of self-microemulsifying liquid and pellet formulations of curcumin,and absorption studies in rats

This study describes the development and characterization of self-microemulsifying drug delivery systems (SMEDDS) in liquid and pellet forms that result in improved solubility, dissolution, and in vivo oral absorption of the poorly water-soluble compound curcumin. Solubility of curcumin was determined in various vehicles, including oils, surfactants and co-surfactants. Pseudo-ternary phase diagrams were constructed to identify the most efficient self-emulsification region. The optimized SMEDDS used for curcumin formulations in liquid and pellet forms contained 70% mixtures of two surfactants: Cremophor EL and Labrasol (1:1), and 30% mixtures of oil: Labrafac PG and Capryol 90 (1:1). The curcumin-SMEDDS in liquid and pellet formulations rapidly formed fine oil-in-water microemulsions, with particle size ranges of 25.8–28.8 nm and 29.6–32.8 nm, respectively. The in vitro rate and extent of release of curcumin from liquid SMEDDS and SMEDDS pellets was about 16-fold higher than that of unformulated curcumin. Plasma concentration–time profiles from pharmacokinetic studies in rats dosed with liquid and pelleted SMEDDS showed 14- and 10-fold increased absorption of curcumin, respectively, compared to the aqueous suspensions of curcumin. Curcumin-SMEDDS liquid and curcumin-SMEDDS pellets were found to be stable up to 6 months under intermediate and accelerated conditions. These studies demonstrate that the new self-microemulsifying systems in liquid and pellet forms are promising strategies for the formulation of poorly soluble lipophilic compounds with low oral bioavailability.     

Biowaiver extension potential and IVIVC for BCS Class II drugs by formulation design: Case study for cyclosporine self-microemulsifying formulation

The objective of this work was to suggest the biowaiver potential of biopharmaceutical classification system (BCS) Class II drugs in self-microemulsifying drug delivery systems (SMEDDS) which are known to increase the solubility, dissolution and oral absorption of water-insoluble drugs. Cyclosporine was selected as a representative BCS Class II drug. New generic candidate of cyclosporine SMEDDS (test) was applied for the study with brand SMEDDS (reference I) and cyclosporine self-emulsifying drug delivery systems (SEDDS, reference II). Solubility and dissolution of cyclosporine from SMEDDS were critically enhanced, which were the similar behaviors with BCS class I drug. The test showed the identical dissolution rate and the equivalent bioavailability (0.34, 0.42 and 0.68 of p values for AUC_0→24h, C_max and T_max, respectively) with the reference I. Based on the results, level A in vitro-in vivo correlation (IVIVC) was established from these two SMEDDS formulations. This study serves as a good example for speculating the biowaiver extension potential of BCS Class II drugs specifically in solubilizing formulation such as SMEDDS.     

Formulation design of self-microemulsifying drug delivery systems for improved oral bioavailability of celecoxib

Celecoxib is a hydrophobic and highly permeable drug belonging to class II of biopharmaceutics classification system. Low aqueous solubility of celecoxib leads to high variability in absorption after oral administration. Cohesiveness, low bulk density and compressibility, and poor flow properties of celecoxib impart complications in it's processing into solid dosage forms. To improve the solubility and bioavailability and to get faster onset of action of celecoxib, the self-microemulsifying drug delivery system (SMEDDS) was developed. Composition of SMEDDS was optimized using simplex lattice mixture design. Dissolution efficiency, t(85%), absorbance of diluted SMEDDS formulation and solubility of celecoxib in diluted formulation were chosen as response variables. The SMEDDS formulation optimized via mixture design consisted of 49.5% PEG-8 caprylic/capric glycerides, 40.5% mixture of Tween20 and Propylene glycol monocaprylic ester (3:1) and 10% celecoxib, which showed significantly higher rate and extent of absorption than conventional capsule. The relative bioavailability of the SMEDDS formulation to the conventional capsule was 132%. The present study demonstrated the suitability of mixture design to optimize the compositions for SMEDDS. The developed SMEDDS formulations have the potential to minimize the variability in absorption and to provide rapid onset of action of celecoxib.     

Enhancing effect of Labrafac Lipophile WL 1349 on oral bioavailability of hydroxysafflor yellow A in rats

The objective of the present investigation was to clarify the mechanism by which Labrafac Lipophile WL 1349 (WL 1349) enhanced the oral bioavailability (BA) of hydroxysafflor yellow A (HSYA), the representative low permeable hydrophilic (biopharmaceutic classification system (BCS) Class III) drug. HSYA-phospholipid complex was prepared, and dissolved into WL 1349 with a certain surfactant to form a stable oil solution. Oral administration of HSYA aqueous solution at a dosage of 4.5mg/kg resulted a low plasma HSYA concentration with C(max) and AUC(0-8h) values of 0.105 microg/ml and 10.29 microg min/ml, respectively. HSYA-phospholipid complex oil solution with the same administration and dosage increased the plasma HSYA concentration significantly with C(max) and AUC(0-8h) values of 2.063 microg/ml and 381.145 microg min/ml, respectively. The results showed that WL 1349 could improve oral absorption of HSYA remarkably. Bioavailability investigations were performed to show WL 1349 dosage independent from HSYA absorption within the dosage from 1 ml/kg to 9 ml/kg. The test of bile duct ligation in rats showed that the oil solution containing WL 1349 did not result in detectable plasma HSYA concentration, but HSYA aqueous solution had the same AUC(0-8h) as the bile duct was not ligated. The in vitro lipolysis experiments of WL 1349 showed that WL 1349 was emulsified by deoxycholate, and then was hydrolyzed to fatty acids and monoglycerides by pancreatic lipase rapidly. The lipolysis products of WL 1349, caprylic acid, capric acid and caprylic and capric acid monoglycerides all improved the BA of HSYA in vivo. The results above indicated the emulsifying by bile, and hydrolysis to fatty acids and monoglycerides by pancreatic lipase was one of the enhancing mechanisms of HSYA-phospholipid complex oil solution absorption.     

Enhanced oral bioavailability of etodolac by self‐emulsifying systems: in‐vitro and in‐vivo evaluation

Objectives The objective of this study was to prepare a self‐emulsifying drug delivery system (SEDDS) for oral bioavailability enhancement of a poorly water‐soluble drug, etodolac. The SEDDS formulations were optimized by evaluating their ability to self‐emulsify when introduced to an aqueous medium under gentle agitation, and by determination of the particle size of the resulting emulsion. Methods An optimized formulation of SEDDS (composed of 20% etodolac, 30% oil Labrafac WL1349, 10% Lauroglycol 90 and 40% Labrasol) was selected for bioavailability assessment in rabbits. The anti‐inflammatory effect was also determined in rats, and compared with powder drug and etodolac suspension in water (50 mg/kg). Key findings The peak plasma concentration of 16.4 ± 1.1 μg/ml appeared after 1.3 ± 0.2 h, whereas with powder drug and etodolac suspension the values were 7.5 ± 0.5 and 10.6 ± 0.7 μg/ml at 4.2 ± 0.4 and 2.4 ± 0.2 h, respectively. The AUC_0–8 of the etodolac SEDDS formulation was 2.3 times that of the pure drug and 1.4 times that of the suspension form. SEDDS formulation exhibits a 21% increase in paw thickness compared with a 39% increase on oral administration of etodolac suspension after 4 h at the same dose of the drug (20 mg/kg). Conclusions The result indicates the utility of SEDDS for the oral delivery of etodolac and potentially other lipophilic drugs.     

自微乳化技术与固体分散技术在改善长春西汀溶出度和生物利用度上的比较(英文)

探讨与比较自微乳化释药系统 (self-microemulsifying drug delivery systems, SMEDDS) 与固体分散体 (solid dispersion, SD) 在改善难溶性药物长春西汀 (vinpocetine, VIP) 溶出度和生物利用度方面的差异。本文选用中链甘油三酯 (Labrafac)、油酸、聚氧乙烯氢化蓖麻油 (Cremophor EL) 和二乙二醇单乙基醚 (Transcutol P) 为材料, 以微粉硅胶吸附制备长春西汀固体自微乳化释药系统 (VIP-SMEDDS); 采用泊洛沙姆188 (F68) 为载体制备长春西汀固体分散体 (VIP-SD)。溶解度实验结果表明, VIP在SMEDDS中的溶解度是SD载体中的17.3倍; 体外溶出度实验表明, VIP-SMEDDS的溶出效果和稳定性比VIP-SD更好; 大鼠体内生物利用度实验表明VIP-SMEDDS是VIP原料的1.89倍, 且不受食物影响, 而VIP-SD的生物利用度与VIP原料相比不具有显著性差异。给药2 h后组织分布结果表明, VIP-SMEDDS在Peyer’s节、肠道、肝脏的药物浓度分别是VIP-SD的3.7、2.2和1.5倍。Caco-2细胞转运实验表明VIP-SMEDDS的表观渗透系数 (P_app, cm·s⁻¹) 是VIP-SD的2.65倍。透射电镜下观察, VIP-SMEDDS组Caco-2细胞间隙是空白对照组的9.6倍, 而VIP-SD组与空白组比较无显著性差异。由此可见, 自微乳化技术在改善长春西汀溶解度、溶出度、肠黏膜透过率、淋巴吸收和生物利用度以及减少食物影响方面优于固体分散技术。     

Combined use of phospholipid complexes and self-emulsifying microemulsions for improving the oral absorption of a BCS class IV compound,baicalin

The aim of this study was to develop a formulation to improve the oral absorption of baicalin (BA) by combining a phospholipid complex (PC) and self-emulsifying microemulsion drug delivery system (SMEDDS), termed BA–PC–SMEDDS. BA–PC was prepared by a solvent evaporation method and evaluated by complexation percentage (CP). The physicochemical properties of BA–PC were determined. The synergistic effect of PC and SMEDDS on permeation of BA was studied in vitro with Caco-2 cells and in situ with a single pass intestinal perfusion model. The improved bioavailability of BA in BA–PC–SMEDDS was confirmed in an in vivo rat model. The CP of BA–PC reached 100% when the molar ratio of drug to phospholipid (PP) was ≥1:1. The solubility of BA–PC increased in both water and octanol, and the log P_o/w of BA–PC was increased significantly. BA–PC–SMEDDS could be dispersed more evenly in water, compared to BA and BA–PC. Both the Caco-2 cell uptake and single-pass intestinal perfusion models illustrated that transport of BA in BA–PC was lower than that of free BA, while improved significantly in BA–PC–SMEDDS. The relative bioavailability of BA–PC(1:2)–SMEDDS was 220.37%. The combination system of PC and SMEDDS had a synergistic effect on improving the oral absorption of BA.KEY WORDS: Baicalin, SMEDDS, Phospholipid complex, Caco-2 cell, Single-pass intestinal perfusion, Bioavailability     

Preparation and in vivo evaluation of SMEDDS (self-microemulsifying drug delivery system) containing fenofibrate

The present work was aimed at formulating a SMEDDS (self-microemulsifying drug delivery system) of fenofibrate and evaluating its in vitro and in vivo potential. The solubility of fenofibrate was determined in various vehicles. Pseudoternary phase diagrams were used to evaluate the microemulsification existence area, and the release rate of fenofibrate was investigated using an in vitro dissolution test. SMEDDS formulations were tested for microemulsifying properties, and the resultant microemulsions were evaluated for clarity, precipitation, and particle size distribution. Formulation development and screening was done based on results obtained from phase diagrams and characteristics of resultant microemulsions. The optimized formulation for in vitro dissolution and pharmacodynamic studies was composed of Labrafac CM10 (31.5%), Tween 80 (47.3%), and polyethylene glycol 400 (12.7%). The SMEDDS formulation showed complete release in 15 minutes as compared with the plain drug, which showed a limited dissolution rate. Comparative pharmacodynamic evaluation was investigated in terms of lipid-lowering efficacy, using a Triton-induced hypercholesterolemia model in rats. The SMEDDS formulation significantly reduced serum lipid levels in phases I and II of the Triton test, as compared with plain fenofibrate. The optimized formulation was then subjected to stability studies as per International Conference on Harmonization (ICH) guidelines and was found to be stable over 12 months. Thus, the study confirmed that the SMEDDS formulation can be used as a possible alternative to traditional oral formulations of fenofibrate to improve its bioavailability.     

Preparation and pharmacokinetics evaluation of oral self-emulsifying system for poorly water-soluble drug Lornoxicam

Abstract

The present work was performed aiming to develop a new solid self-emulsifying system (SMEDDS) for poorly water-soluble drug Lornoxicam and evaluate the bioavailability in Wister rats by oral gavage. Liquid SMEDDS of Lornoxicam was formulated with Labrafil M 1944 CS as oil phase, Kolliphor HS 15 as a surfactant and Transcutol HP as a cosurfactant after screening various vehicles. The microemulsion system selected from the phase diagram and optimized by central composite design (CCD) response surface method was transformed into solid-SMEDDS (S-SMEDDS) by lyophilization using sucrose as cryoprotectant. The formulations were further characterized by the particle size, poly dispersity index (PDI), self-emulsifying time, zeta potential, transmission electron microscope (TEM), differential scanning calorimeter (DSC), in vitro drug release and in vivo pharmacokinetics. Results of DSC studies confirmed that the drug was incorporated in the S-SMEDDS. The in vitro drug release from Lornoxicam SMEDDS was found to be greatly higher in comparison with that from the commercial tablets. It was indicated that SMEDDS might be effective in reducing the effect of pH variability of Lornoxicam and improving the release performance of Lornoxicam. HPLC system was applied to study the concentration of Lornoxicam in the plasma of the Wister rats after oral administration of Lornoxicam SMEDDS and Lornoxicam commercial tablets. The pharmacokinetics parameters of the rats were C_max 1065.91?±?224.90 and 1855.22?±?748.25?ngmL^?1, T_max were 2.5?±?0.4?h and 1.8?±?0.5?h, and AUC_0～t were 5316.35?±?323.62 and 7758.07?±?241.57?ngmL^?1?h, respectively. Calculated by AUC_0～∞, the relative bioavailability of Lornoxicam S-SMEDDS was 151.69?±?15.32%. It suggested that this S-SMEDDS could be used as a successful oral solid dosage form to improve the solubility and bioavailability of poorly water-soluble drug Lornoxicam as well.     

Enhanced oral bioavailability of piperine by self-emulsifying drug delivery systems: in vitro,in vivo and in situ intestinal permeability studies

Abstract

The main purpose of this work was to develop and evaluate a self-emulsifying drug delivery system (SEDDS) of piperine to enhance its solubility and bioavailability. The formulation was optimized by solubility test and ternary phase diagrams. Then physiochemical properties and in vitro release of SEDDS were characterized. In vivo pharmacokinetics study and in situ single-pass intestinal perfusion were performed to investigate the effects of SEDDS on the bioavailability and intestinal absorption of piperine. The optimized formulation was composed of ethyl oleate, Tween 80 and Transcutol P (3:5.5:1.5, w/w), with the level of the piperine reached 2.5% (w/w). The in vitro dissolution rates of piperine SEDDS were significantly higher than the self-prepared capsules. In vivo pharmacokinetic study showed C_max1, C_max2 and area under the curve of piperine after oral administration of SEDDS in rats were 3.8-, 7.2- and 5.2-fold higher than the self-prepared capsules, respectively, and the relative bioavailability of SEDDS was 625.74%. The in situ intestinal absorption study revealed that the effective permeability and the effective absorption rate values of piperine for SEDDS were significantly improved comparing to solutions (p?<?0.01). So SEDDS formulation could improve the oral bioavailability and intestinal absorption of piperine effectively.     

Enhancing both oral bioavailability and brain penetration of puerarin using borneol in combination with preparation technologies

Now there are few good oral preparations of puerarin used in cerebrovascular diseases because of its poor oral absorption caused by the low water solubility and the poor penetration into brain. In this study, three oral formulations of puerarin, nanocrystals suspension (NCS), inclusion compounds solution (ICS) and self-microemulsifying drug delivery system (SMEDDS) were prepared with borneol as an oral brain-targeting enhancer. A rat syngeneic in vitro model of the brain–blood barrier (BBB) was established to investigate effects of borneol on the permeability of puerarin across the BBB. The pharmacokinetics of puerarin in mice after oral administration was investigated by a high performance liquid chromatography-mass spectrometry/mass spectrometry (HPLC-MS/MS) method. The in vitro BBB model study showed the permeability of puerarin was increased significantly (p?p?plasma) and in brain (AUC_brain) for SMEDDS were significantly higher than those for NCS (p?p?相似文献   

Co-delivery of honokiol,a constituent of Magnolia species,in a self-microemulsifying drug delivery system for improved oral transport of lipophilic sirolimus

Sirolimus is recognized as a P-glycoprotein (P-gp) substrate with poor water-solubility. To improve its solubility and bioabsorption, self-microemulsifying drug delivery systems (SMEDDS) containing a novel P-gp inhibitor, honokiol, were prepared. The aim of this work was to evaluate the enhanced transport of sirolimus SMEDDS as well as the roles of honokiol. In situ single-pass intestinal perfusion and in vitro human colon adenocarcinoma (Caco-2) cell models were applied to study the effects of honokiol within SMEDDS on the transport of sirolimus. The results indicated that a combination of honokiol with sirolimus in SMEDDS did not significantly alter the particle size, polydispersity index and release of drugs. In addition, the absorption rate constant (K_a) as well as the effective permeability coefficients (P_eff) of sirolimus in situ intestinal absorption, and the apparent permeability coefficients (P_app) of sirolimus in caco-2 cells were significantly enhanced by cremophor EL-based SMEDDS with honokiol as compared with those of SMEDDS without honokiol. Rhodamine123 uptake rate in caco-2 cells and in vitro cytotoxicity of sirolimus were enhanced by honokiol in SMEDDS indicating a substantial P-gp inhibition of honokiol. In conclusion, coadministration of honokiol with poor soluble P-gp substrate in SMEDDS, could serve as a favorable approach for oral delivery.     

Self-microemulsifying drug delivery system (SMEDDS) – challenges and road ahead

Abstract

Self-microemulsifying drug delivery system (SMEDDS) has emerged as a vital strategy to formulate poor water soluble compounds for bioavailability enhancement. However, certain limitations are associated with SMEDDS formulations which include in vivo drug precipitation, formulation handling issues, limited lymphatic uptake, lack of predictive in vitro tests and oxidation of unsaturated fatty acids. These limitations restrict their potential usage. Inclusion of polymers or precipitation inhibitors within lipid based formulations helps to maintain drug supersaturation after dispersion. This, thereby, improves the bioavailability and reduces the variability on exposure. Also, formulating solid SMEDDS helps to overcome liquid handling and stability problems. Usage of medium chain triglycerides (MCT) and suitable antioxidants to minimize oxidation of unsaturated fatty acids are few of the steps to overcome the limitations associated with SMEDDS. The review discussed here, in detail, the limitations of SMEDDS and suitable measures that can be taken to overcome them.     

Oral bioavailability enhancement of vinpocetine using self-microemulsifying drug delivery system containing long chain triglycerides: Preparation and in vitro/in vivo evaluation

Vinpocetine, a widely used neurotropic agent, has low oral bioavailability due to its poor solubility and extensive hepatic first-pass metabolism. In the present work, self-microemulsifying drug delivery systems (SMEDDS) employing long chain triglycerides (LCT) were successfully developed to increase vinpocetine’s solubility and reduce its hepatic first pass metabolism, thus enhancing its overall oral bioavailability. Maisine^?35-1 was chosen as the lipid component in the formulated SMEDDS as it showed the maximal vinpocetine solubility within different LCT tested. Feasibility of obtaining SMEDDS, containing Maisine^?35-1, together with Transcutol^®HP and either Cremophor^®EL or Tween 80, was evaluated using ternary phase diagrams. In vitro release studies performed in phosphate buffer of pH 7.4 illustrated that extent of vinpocetine release from SMEDDS was drastically higher than that obtained from commercial Cavinton^® tablets. The industrial usefulness of the developed SMEDDS was evaluated regarding their moisture sorption isotherms when filled into gelatin capsules and stored at different relative humidity. Vinpocetine’s optimal SMEDDS did not induce gross changes in the gastrointestinal mucosa of rats at the investigated dose. Moreover, it significantly improved the relative oral bioavailability of vinpocetine compared to Cavinton^® tablets. Accordingly, this study suggests that SMEDDS containing LCT under proper optimization and safety assessment can be effectively utilized for oral bioavailability enhancement of vinpocetine.     

In vitro and in vivo evaluation of a self-microemulsifying drug delivery system for the poorly soluble drug fenofibrate

Fenofibrate is indicated in hypercholesterolemia and hypertriglyceridemia alone or combined (types IIa, IIb, III, IV, and V dyslipidemias). However, due to its low solubility in water, it has low bioavailability after oral administration. In order to improve the dissolution rate, fenofibrate was formulated into a self-microemulsifying drug delivery system (SMEDDS). We used pseudoternary phase diagrams to evaluate the area of microemulsification, and an in vitro dissolution test was used to investigate the dissolution rate of fenofibrate. The optimized formulation for in vitro dissolution and bioavailability assessment consisted of propylene glycol laurate (Lauroglycol FCC) (60 %), macrogol-15-hydroxystearate (Solutol HS 15) (27 %), and diethylene glycol monoethyl ether (Transcutol-P) (13 %). The mean droplet size of the oil phase in the microemulsion formed by the SMEDDS was 131.1 nm. The dissolution rate of fenofibrate from SMEDDS was significantly higher than that of the reference tablet. In vivo pharmacokinetics study of fenofibrate in beagles administered SMEDDS-A form resulted in a 3.7-fold increase in bioavailability as compared with the reference drug. Our studies suggested that the fenofibrate containing SMEDDS composition can effectively increase the solubility and oral bioavailability of poorly water-soluble drugs.     

Self-nanoemulsifying drug delivery system (SNEDDS) of the poorly water-soluble grapefruit flavonoid Naringenin: design,characterization, in vitro and in vivo evaluation

Abstract

Naringenin (NRG), predominant flavanone in grapefruits, possesses anti-inflammatory, anti-carcinogenic, hepato-protective and anti-lipid peroxidation effects. Slow dissolution after oral ingestion due to its poor solubility in water, as well as low bioavailability following oral administration, restricts its therapeutic application. The study is an attempt to improve the solubility and bioavailability of NRG by employing self-nanoemulsifying drug delivery technique. Preliminary screening was carried out to select oil, surfactant and co-surfactant, based on solubilization and emulsification efficiency of the components. Pseudo ternary phase diagrams were constructed to identify the area of nanoemulsification. The developed self-nanoemulsifying drug delivery systems (SNEDDS) were evaluated in term of goluble size, globule size distribution, zeta potential, and surface morphology of nanoemulsions so obtained. The TEM analysis proves that nanoemulsion shows a droplet size less than 50?nm. Freeze thaw cycling and centrifugation studies were carried out to confirm the stability of the developed SNEDDS. In vitro drug release from SNEDDS was significantly higher (p?<?0.005) than pure drug. Furthermore, area under the drug concentration time-curve (AUC_0–24) of NRG from SNEDDS formulation revealed a significant increase (p?<?0.005) in NRG absorption compared to NRG alone. The increase in drug release and bioavailability as compared to drug suspension from SNEDDS formulation may be attributed to the nanosized droplets and enhanced solubility of NRG in the SNEDDS.