Improvement of dissolution profile of eplerenone with solidified self-emulsifying drug delivery systems (S-SEDDS).

CONTEXT: Eplerenone is a member of antihypertensives used individually or in combination with other medicines. Eplerenone exhibits poor solubility and is considered a class II drug. OBJECTIVE: Increasing the solubility of eplerenone by using both liquid and solid self-emulsifying drug delivery systems as an alternative to its marketed tablet product. METHODS: Solubility studies of eplerenone were done with different oils, surfactants, and co-surfactants to determine which one has the highest solubility for eplerenone and determine the preference in the formulations of liquid self-emulsifying drug delivery system. The solidification process was carried out with the adsorption to solid carrier method. Optimal ratios of components were specified with the pseudo-ternary phase diagram technique. Self-emulsifying drug delivery system formulations were characterized in terms of chemical interaction, droplet size/distribution, crystallization behaviors, and rheological evaluation. In vitro drug release studies were conducted and compared to pure drugs and marketed products. RESULTS: The solubility screening results showed high solubility of EPL in triacetin (11.99 mg/mL) as oil, Kolliphor®EL (≈ 2.65 mg/mL), and Tween80 (≈ 1.91 mg/mL) as surfactant and polyethylene glycol 200 (PEG200) (≈ 8.50 mg/mL), dimethyl sulfoxide (≈ 7.57 mg/mL), TranscutolP (≈ 6.03 mg/mL) as co-surfactant, respectively. Rheology studies revealed that liquid self-emulsifying drug delivery formulations exhibited non-Newtonian pseudoplastic flow. CONCLUSION: Solid self-emulsifying drug delivery systems prepared with Aerosil and Neusilin have shown tremendous improvement in terms of eplerenone dissolution by releasing the entire dose with boosted effect within 5 and 30 min respectively compared to the marketed product and pure eplerenone (p < 0.05).

Development of a Solid Formulation Containing a Microemulsion of a Novel Artemisia Extract with Nematocidal Activity for Oral Administration.

BACKGROUND: Intestinal nematode infections are usually treated with benzimidazole drugs, but the emergence of resistance to these drugs has led to an increasing demand of new anthelmintic strategies. A new microemulsion formulation (ME) consisting of an Artemisia absinthium extract with proven nematocidal efficacy was previously developed. The aim of our study is to implement a D-optimal mixture design methodology to increase the amount of a silica material (loaded with this ME) in a tablet formulation, considering its tensile strength and disintegration time. METHODS: 16 experiments or combinations of the 6 tablet components (loaded silica, microcrystalline cellulose, polyvinylpyrrolidone, croscarmellose, Syloid® 244 FP and magnesium stearate) were assessed. Tensile strength and disintegration time models were developed, and an optimization process was carried out. RESULTS: Tensile strength was improved by increasing the polyvinylpyrrolidone content, while croscarmellose decreased the disintegration time. The optimized powder mixture contains 49.7% w/w of the loaded silica material. A compression force of 12 kN was applied to the powder mixture to form tablets with a tensile strength of 2.0 MPa and a disintegration time of 3.8 min. CONCLUSIONS: Our results show that D-optimal mixture designs provide a promising approach to formulate liquid-loaded silica materials.

Solid formulation of a supersaturable self-microemulsifying drug delivery system for valsartan with improved dissolution and bioavailability.

In order to improve the dissolution and oral bioavailability of valsartan (VST), and reduce the required volume for treatment, we previously formulated a supersaturable self-microemulsifying drug delivery system (SuSMEDDS) composed of VST (80 mg), Capmul® MCM (13.2 mg), Tween® 80 (59.2 mg), Transcutol® P (59.2 mg), and Poloxamer 407 (13.2 mg). In the present study, by using Florite® PS-10 (119.1 mg) and Vivapur® 105 (105.6 mg) as solid carriers, VST-loaded solidified SuSMEDDS (S-SuSMEDDS) granules were successfully developed, which possessed good flow properties and rapid drug dissolution. By introducing croscarmellose sodium (31 mg) as a superdisintegrant, S-SuSMEDDS tablets were also successfully formulated, which showed fast disintegration and high dissolution efficiency. Preparation of granules and tablets was successfully optimized using D-optimal mixture design and 3-level factorial design, respectively, resulting in percentage prediction errors of <10%. In pharmacokinetic studies in rats, the relative bioavailability of the optimized granules was 107% and 222% of values obtained for SuSMEDDS and Diovan® powder, respectively. Therefore, we conclude that novel S-SuSMEDDS formulations offer great potential for developing solid dosage forms of a liquefied formulation such as SuSMEDDS, while improving oral absorption of drugs with poor water solubility.

Development of a solidified self-microemulsifying drug delivery system (S-SMEDDS) for atorvastatin calcium with improved dissolution and bioavailability.

To improve the dissolution and oral bioavailability (BA) of atorvastatin calcium (ATV), we previously introduced an optimized self-microemulsifying drug delivery system (SMEDDS) using Capmul(®) MCM (oil), Tween(®) 20 (surfactant), and tetraglycol (cosurfactant). In this study, various solid carriers were employed to develop a solidified SMEDDS (S-SMEDDS): mannitol (M) and lactose (L) as water-soluble carriers, and Sylysia(®) 350 (S) and Aerosil(®) 200 (A) as water-insoluble carriers. Maximum solidifying capacities (SCmax) of water-insoluble carriers were significantly greater than those of water-soluble carriers were. The resultant powders were free flowing with an angle of repose <40° and Carr's index 5-20%, regardless of the solid carrier types. S-SMEDDS with mannitol (S(M)-SMEDDS) or lactose (S(L)-SMEDDS) had a smaller droplet size and greater dissolution than S-SMEDDS with Sylysia(®) 350 (S(S)-SMEDDS) or Aerosil(®) 200 (S(A)-SMEDDS). Following oral administration of various formulations to rats at a dose equivalent to 25mg/kg of ATV, plasma drug levels were measured by LC-MS/MS. The relative BAs (RBAs) of SMEDDS, S(M)-SMEDDS, and S(S)-SMEDDS were 345%, 216%, and 160%, respectively, compared to that of ATV suspension. Additionally, at a reduced dose of ATV equivalent to 5mg/kg, the RBAs of S(M)-SMEDDS and S(S)-SMEDDS compared to that of SMEDDS were 101% and 65%, respectively. These results suggest that S(M)-SEMDDS offers great potential for the development of solid dosage forms with improved oral absorption of drugs with poor water solubility.

Formulation optimization of aprepitant microemulsion-loaded silicated corn fiber gum particles for enhanced bioavailability.

The present investigation was aimed at development of silicate corn fiber gum (SCFG) particles as superior solid carrier for the preparation of Aprepitant (APT)-loaded self-emulsifying powder (SEP) system. 2(4) D-optimal mixture design with three level process variables was employed to develop SCFG particles, utilizing flow descriptors and hydrophobicity descriptors as response variables. The results indicated that blending of CFG (51.4% w/w) and magnesium silicate (MS) (48.6% w/w) using freeze-drying technique was found to have highest desirability (0.904). The developed SEP showed highest oil desorbing capacity, low self-emulsification time and highest drug content. It was observed that SCFG-SEP (F2 formulation) showed lowest PDI (0.2445 ± 0.03) as well as smallest particle size (127 ± 5.8 nm). The droplets were uniform and maintain their integrity after reconstitution (TEM analysis). Furthermore, APT-loaded SEP showed enhanced in vitro dissolution (4 folds) and ex vivo performance (7-fold enhanced Papp) as compared to pure APT. Furthermore, in vivo pharmacokinetic study showed that significant enhancement (p > 0.05) in Cmax was evident with APT-loaded F2 (SCFG-SEP) (1.93-fold) and F4 (Aerosil 200-SEP) (1.58-fold). The data also suggested increase in absorption rate when APT incorporated into SCFG-SEP. Thus, findings pointed toward enhanced bioavailability of APT when loaded into SCFG particles. Overall, the developed SCFG particles could be considered as a better alternative to already available solid carrier(s).

Preparation of fenofibrate dry emulsion and dry suspension using octenyl succinic anhydride starch as emulsifying agent and solid carrier.

Purpose of this study was to investigate the ability of octenyl succinic anhydride (OSA) starch as emulsifier and solid carrier in dry emulsion (DE) and dry suspension (DS) formulations. Fenofibrate (FF) was loaded at lower and higher than its saturation concentration in oil phase to prepare the DE and DS by spray drying method. The DE and DS were successfully prepared with 36-48% and 46% production yield, respectively. After reconstitution in water, the emulsion with mean droplet size of 1-2 µm was obtained. Solid state characterization revealed the amorphous state of FF and the crystalline state of OSA starch in both DE and DS formulations. Both DE and DS enhanced FF dissolution rate compared to pure material and DS showed the highest dissolution rate. The DE and DS could be compressed to the tablets with acceptable disintegration time and without changeable dissolution profile. Moreover, the dissolution profiles of both DE and DS remained unchanged after 2 months storage at 40 °C.

Role of solid carriers in pharmaceutical performance of solid supersaturable SEDDS of celecoxib.

Self emulsifying drug delivery system (SEDDS) has been increasingly used for improving the oral bioavailability of poorly water soluble drugs. SEDDS can be solidified by adsorbing them on different solid carriers. In the present study, the impact of properties of solid carrier on drug release profile from solid SEDDS was investigated. Celecoxib (CEL) loaded supersaturable SEDDS (S-SEDDS) was prepared and optimized by using optimal response surface design. Optimum composition of S-SEDDS corresponded to 10:45:45% v/v ratio of oil (Capryol 90), surfactant (Tween 20) and cosurfactant (Transcutol HP) with Soluplus (40 mg) as precipitation inhibitor. Different grades of silicon dioxide were selected based on their properties like surface area, porosity and hydrophobicity-hydrophilicity, and used for preparation of solid S-SEDDS (SS-SEDDS) by adsorption method. All SS-SEDDS formulations in release studies, gave droplet size, PDI and zeta potential similar to S-SEDDS. The percent drug release after 120min from CEL powder, S-SEDDS and SS-SEDDS with Sylysia 350 fcp, Aerosil 300 Pharma, Aerosil 200 Pharma and Aerosil R 972 Pharma was found to be 0.58%, 100%, 38.44%, 9.63%, 2.53% and 5.99%, respectively. Drug release profiles were compared by using model independent methods. The differential drug release behavior of SS-SEDDS was attributed to the different physico-chemical properties of solid carriers. SS-SEDDS with Sylysia 350 fcp showed higher drug release and greater dissolution efficiency. Oral bioavailability study also demonstrated 2.34 fold increase in Cmax and 4.82 fold increase in AUC (0-24h) when compared with CEL powder. This study highlights the rational for selection of solid carriers in the formulation development of solid SEDDS.

Solid self-nanoemulsifying drug delivery system (SNEDDS) for enhanced oral bioavailability of poorly water-soluble tacrolimus: physicochemical characterisation and pharmacokinetics.

To develop a novel self-nanoemulsifying drug delivery system (solid SNEDDS) with better oral bioavailability of tacrolimus, the solid SNEDDS was obtained by spray-drying the solutions containing the liquid SNEDDS and colloidal silica. Its reconstitution properties were determined and correlated to solid state characterisation of the powder. Moreover, the dissolution and pharmacokinetics in rats was done in comparison to the commercial product. Among the liquid SNEDDS formulations tested, the liquid SNEDDS comprised of Capryol PGMC, Transcutol HP and Labrasol (10:15:75, v/v/v) presented the highest dissolution rate. In the solid SNEDDS, this liquid SNEDDS was absorbed in the pores and attached onto the surface of the colloidal silica. Drug was present in the amorphous state in it. The solid SNEDDS with 5% w/v tacrolimus produced the nanoemulsions and improved the oral bioavailability of tacrolimus in rats. Therefore, this solid SNEDDS would be a potential candidate for enhancing the oral bioavailability of tacrolimus.

Solid self-nanoemulsifying drug delivery system (S-SNEDDS) for oral delivery of glimepiride: development and antidiabetic activity in albino rabbits.

CONTEXT: This study presents novel self-nanoemulsifying drug delivery system potential of oral delivering which leads poorly aqueous soluble drug glimepiride. OBJECTIVE: The objective of this study was to prepare solid self-nanoemulsifying drug delivery system (S-SNEDDS) for the improved oral delivery of glimepiride and to evaluate its therapeutic efficacy in albino rabbits. RESULTS AND DISCUSSION: The droplet size analyses revealed a droplet size of less than 200 nm. The solid state characterization of S-SNEDDS by scanning electron microscopy (SEM), X-ray powder diffraction and differential scanning calorimetry (DSC) revealed the absence of crystalline glimepiride in the S-SNEDDS. The in vitro dissolution studies revealed that the significant improvement in glimepiride release characteristics. The effect of S-SNEDDS on therapeutic efficacy of glimepride was assessed in albino rabbits by monitoring blood glucose levels and compared with free drug suspension, L-SNEDDS. The S-SNEDDS showed significant (p < 0.05) increase in in vitro drug release and therapeutic efficacy as compared with free drug. CONCLUSION: This study demonstrated that S-SNEDDS is a promising novel drug delivery system of glimepride to enhance oral delivery.

A novel suspended-solid phase photobioreactor to improve biomass production and separation of microalgae.

A novel suspended-solid phase photobioreactor (ssPBR) was proposed in this paper to solve the problem of microalgal expensive and complex harvest system for biomass/biofuel production. In this ssPBR, solid carriers were added and kept suspended by aeration. Part of microalgae could attach and grow on the carriers. By catching carriers, microalgae could easily be separated from liquid phase. Three kinds of Carriers A, B, C made of cotton, mohair and linen, respectively, were used in this study. Compared with the reactor without carriers, the biomass production in each ssPBR was increased by adding these three kinds of carriers at a dosage of 2g/L, and the maximum increments of biomass were 2.2×10(5) (10.3%), 7.8×10(4) (3.9%) and 4.4×10(5) (20.5%)cells/mL, respectively. By increasing the dosage of Carriers-C to 4g/L, the maximum increment of microalgal biomass could reach up to about 30% in the ssPBR compared with control group.