Development of phyllanthin-loaded self-microemulsifying drug delivery system for oral bioavailability enhancement

Preparation and in vitro/in vivo evaluation of a self-microemulsifying drug delivery system containing chrysin

OBJECTIVE

To prepare a self-microemulsifying drug delivery system (SMEDDS) to increase the solubility and oral bioavailability of chrysin.

METHODS

The preparation conditions were determined using factor analysis method. Preliminarily screening was conducted using compatibility tests and pseudo-ternary phase diagram studies. The central composite design-response surface methodology was used to determine the maximum drug loading and optimize SMEDDS formation, as characterized by surface morphology, pH, diameter, polydispersity index (PDI), zeta potential, and phase type. In vitro release of chrysin-suspension and chrysin-SMEDDS was investigated using the bulk-equilibrium reverse dialysis bag technique. Short-term stability of chrysin-SMEDDS at high and low temperatures was assessed. Pharmacokinetic behaviors were evaluated after intragastric and intravenous administration to rats.

RESULTS

The final optimal formulation was medium chain triglyceride:oleic acid:Cremophor RH40: Transcutol HP (w/w) (12%:12%:32%:44%), with a drug loading capacity of 5 mg/g. Diluted chrysin-SMEDDS was characterized as an oil-in-water type and spherical, with a diameter, pH, PDI, and zeta potential of 28.26 ± 0.83 nm, 5.60 ± 0.84, 0.18 ± 0.01, and -23.13 ± 0.95 mV, respectively. The release speed of chrysin-SMEDDS was significantly higher than that of chrysin-suspension, and the release process was not affected by the media pH. In vivo pharmacokinetic data revealed that the oral bioavailability of chrysin-SMEDDS was 2.7-fold higher than that of chrysin suspension, compared with the chrysin microemulsion.

CONCLUSION

The optimal SMEDDS formulation increased the dissolution and oral bioavailability of chrysin and may be useful for investigating chrysin efficacy in animal disease models and toxicokinetic studies.

Preparation and evaluation of oral self-microemulsifying drug delivery system of Chlorophyll

OBJECTIVE

This study was aimed at improving the water solubility and oral bioavailability of Chl by self-microemulsifying drug delivery system (Chl-SMEDDS).

METHODS

Compatibility experiments, pseudo-ternary phase diagram and central composite design were used to optimize the formulation. The selected systems were further evaluated for physical characteristics, including particle size, zeta potential, and appearance. The stability, in vitro dispersion test, and in vivo intestinal perfusion experiments were used to evaluate the SMEDDS.

RESULTS

The optimal composition of Chl-SMEDDS included: Labrafil M 1944 CS (35%), kolliphor RH 40 (46%), Transcutol HP (19%) and 60 mg/g Chl. The appearance of water emulsified Chl-SMEDDS was green and transparent. The particle size, ζ-potential, and transmission electron microscopy studies showed that spherical globules of Chl-SMEDDS with a size of about 22.82 ± 1.29 nm and a negative surface charge of -24.21 ± 3.45 mV were obtained. Chl-SMEDDS could remain stable at 25 °C and 4 °C for at least 6 months. The dispersion test showed that Chl-SMEDDS dispersed spontaneously to form microemulsion after disintegration of capsule shell and 90% drug dispersed in just 30 min in pH 1.2 HCl without any drug precipitation during the test period. In vivo intestinal perfusion experiment revealed that the main absorption site for Chl-SMEDDS was duodenum.

CONCLUSIONS

This study indicates that SMEDDS formulation could be an effective strategy for the oral administration of Chl.

Effects of Hydrophilic Carriers on Structural Transitions and In Vitro Properties of Solid Self-Microemulsifying Drug Delivery Systems

Self-microemulsifying drug delivery systems (SMEDDS) offer potential for improving the oral bioavailability of poorly water-soluble drugs. However, their susceptibilities during long term storage and in vivo precipitation issues limit their successful commercial application. To overcome these limitations, SMEDDS can be solidified with solid carriers, thus producing solid self-microemulsifying drug delivery systems (S-SMEDDS). In this study, effects of various hydrophilic carriers on structural transitions and in vitro properties of S-SMEDDS were investigated in order to set up in vitro methods for screening out appropriate carriers for S-SMEDDS. Liquid SMEDDS was prepared and characterized using nimodipine as a model drug. The effects of various hydrophilic carriers on internal microstructure and solubilization of SMEDDS were investigated by conductivity measurement and in vitro dispersion test. The results showed that hydrophilic carriers including dextran 40, maltodextrin and PVP K30 seemed to delay the percolation transition of SMEDDS, allowing it to maintain a microstructure that was more conducive to drug dissolution, thus significantly increasing the solubilization of nimodipine in the self-microemulsifying system and decreasing drug precipitation when dispersed in simulated gastric fluid. S-SMEDDS of nimodipine were prepared by using spray drying with hydrophilic carriers. The effects of various hydrophilic carriers on in vitro properties of S-SMEDDS were investigated by using SEM, DSC, PXRD and in vitro dissolution. The results showed that properties of hydrophilic carriers, especially relative molecular mass of carriers, had obvious influences on surface morphologies of S-SMEDDS, reconstitution of microemulsion and physical state of nimodipine in S-SMEDDS. Considering that in vitro properties of S-SMEDDS are closely related to their pharmacokinetic properties in vivo, the simple and economical in vitro evaluation methods established in this paper can be used to screen solid carriers of S-SMEDDS well.

Self-microemulsifying Drug Delivery System for Problematic Molecules: An Update

BACKGROUND

The poor bioavailability of a problematic molecule is predominantly due to its high lipophilicity, low solubility in gastric fluids and/or high fist pass metabolism. Self microemulsifying drug delivery system (SMEDDS), a lipidic type IV nano-formulation has been of interest in the field of pharmaceutical research due to its potential for tailoring the physicochemical properties of pharmaceutical molecules.

METHODS

This review provides insights on various recent innovations and reports from the past seven years (2012-2019) of self-emulsifying formulations for the delivery of various types of poorly soluble drugs, phytoconstituents and high molecular peptides and gives exhaustive details of the outcome of the endeavors in this field.

RESULTS

Various types of innovative formulations have been molded from SMEDDS like selfemulsifying powders, granules, tablets, pellets, eutectic and cationic formulations. Till date, many research reports and patents have been filed on self-emulsifying dosage forms and many formulations have gained US-FDA approvals which are summarized in the review article.

CONCLUSION

This review content highlighted the increasing scope of SMEDDS in augmenting the physiochemical properties of an API, the variegated formulation types and the attributes of API that can be improved by SMEDD based formulations.

Experimental design-based optimization of lipid nanocarrier as delivery system against Mycobacterium species: in vitro and in vivo evaluation

The study aimed to optimize self-nanoemulsifying drug delivery system using experimental design using excipients holding innate anti-mycobacterium activities followed with characterizations for responses such as optical clarity (Y₁), zone of inhibition (ZOI) against Mycobacterium smegmatis strains (Y₂, Y₃), and globular size (Y₄). The optimized formulations (OF1-OF3) were further characterized for responses and evaluated for zeta potential, minimum inhibition concentration (MIC) against non-pathogenic and tubercular strains, morphological (electron microscopy and atomic force microscopy), and confocal laser scanning microscopy (CLSM) studies. The desirability analysis suggested that the predicted values of the OF1 for the responses Y₁, Y₂, Y₃, and Y₄ were 0.137, 22.77 mm, 21.9 mm, and 191.11 nm, respectively. The morphological assessment confirmed the in vitro studies and established the inhibition mechanism as evidenced with oozing, ablation, and cell-wall fragmentation followed with cell disruption. The OF1, OF2, and OF3 showed an MIC value at 8.8 ± 0.56 mg/ml, 12.5 ± 0.22 mg/ml, and 15.0 ± 0.4 mg/ml, respectively, corroborating effectiveness against tubercular strain. CLSM studies revealed 75.1, 80.3, and 88.7% as an intense fluorescence intensity of OF1, OF2, and OF3, respectively, as compared with dye solution (∼53%). Conclusively, it can be inferred that the delivery of anti-tubercular drugs might be reassessed using excipients with inherent anti-mycobacterium activities.

A novel monolithic controlled delivery system of resveratrol for enhanced hepatoprotection: nanoformulation development, pharmacokinetics and pharmacodynamics

The current investigation aims to present a novel solid lipid-based nanoparticulate system of resveratrol (RV) for the effective treatment of liver cirrhosis. A simplified solvent injection method was employed and the Box-Behnken experimental design was applied for optimization to get a window particle size of 150-200 nm having maximum entrapment efficiency as well as % release. Optimized resveratrol solid lipid nanoparticles (RV-SLNs) (SR-1) of appropriate characteristics (particle size = 191.1 ± 10.44 nm; zeta potential= -13.56 ± 4.14 mV; entrapment efficiency = 75.23 ± 3.85%; maximum % release = 80.53 ± 3.99%) were produced. Differential scanning calorimetry and X-ray diffraction studies were carried out which collectively proved the reduced crystallinity and stability enhancing the effect of the SLNs. Improved drug stability was further established by the appreciable shelf-life of the formulation from International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use (ICH)-recommended accelerated stability studies. In vivo studies revealed nearly five-fold increase in the bioavailability of SR-1 (AUC0→∞=3411 ± 170.34 µg/ml/h) as compared to RV suspension (AUC0→∞=653.5 ± 30.10 µg/ml/h). Pharmacodynamic data exhibited a significant decrease in the serum biomarker enzymes (serum glutamic oxalo-acetic transaminase (SGOT), serum glutamic pyruvic transaminase (SGPT) and alkaline phosphatase) after oral administration of RV-SLNs as compared to control and marketed (SILYBON(®)) formulations against paracetamol-induced liver cirrhosis. The effect of the treatment was confirmed by the histopathology of the liver microtome sections. Finally, reverse transcriptase-polymerase chain reaction studies were conducted on isolated liver mRNA from SR-1 treated animals and significant down-regulation of tissue inhibitor of metalloproteinases-1 and nuclear factor-kB was witnessed.

Evidences for anti-mycobacterium activities of lipids and surfactants

Tuberculosis is the most widespread and deadly airborne disease caused by Mycobacterium tuberculosis. The two-pronged lethal effect on the bacteria using lipids/surfactants and anti-tubercular drugs may render the miniaturization of dose owing to synergistic and tandem effect of both. The current research has been focused on screening and evaluating various lipids/surfactants possessing inherent anti-mycobacterium activity that can ferry the anti-tubercular drugs. In vitro anti-mycobacterium activity was evaluated using agar well diffusion method. Furthermore, time-concentration dependent killing and DNA/RNA content release studies were performed to correlate the findings. The exact mechanism of bacterial killing was further elucidated by electron/atomic force microscopy studies. Finally, to negate any toxicity, in vitro hemolysis and toxicity studies were performed. The study revealed that capmul MCM C-8, labrasol and acconon C-80 possessed highest in vitro anti-mycobacterium activity. Electron/atomic force microscopy results confirmed in vitro studies and verified the killing of Mycobacterium owing to the release of cytoplasmic content after cell wall fragmentation and disruption. Moreover, the least hemolysis and hundred percent survivals rate of mice using the excipients demonstrated the safety aspects of explored excipients that can ferry the anti-tubercular drugs. The present study concluded the safe, efficient and synergistic activity of the explored excipients and anti-tubercular drugs in controlling the menace of tuberculosis.

Development and Evaluation of Liquid and Solid Self-Emulsifying Drug Delivery Systems for Atorvastatin

The objective of this work was to design and characterize liquid and solid self-emulsifying drug delivery systems (SEDDS) for poorly soluble atorvastatin. To optimize the composition of liquid atorvastatin-SEDDS, solubility tests, pseudoternary phase diagrams, emulsification studies and other in vitro examinations (thermodynamic stability, droplet size and zeta potential analysis) were performed. Due to the disadvantages of liquid SEDDS (few choices for dosage forms, low stability and portability during the manufacturing process), attempts were also made to obtain solid SEDDS. Solid SEDDS were successfully obtained using the spray drying technique from two optimized liquid formulations, CF3 and OF2. Despite liquid SEDDS formulation, CF3 was characterized by lower turbidity, higher percentage transmittance and better self-emulsifying properties, and based on the in vitro dissolution study it can be concluded that better solubilization properties were exhibited by solid formulation OF2. Overall, the studies demonstrated the possibility of formulating liquid and solid SEEDS as promising carriers of atorvastatin. SEDDS, with their unique solubilization properties, provide the opportunity to deliver lipophilic drugs to the gastrointestinal tract in a solubilized state, avoiding dissolution—a restricting factor in absorption rate of BCS Class 2 drugs, including atorvastatin.

Antioxidant and hepatoprotective effects of mixed micellar lipid formulation of phyllanthin and piperine in carbon tetrachloride-induced liver injury in rodents

Phyllanthin, a sparingly water-soluble hepatoprotective lignin obtained from Phyllanthus amarus Schum. et Thonn. (Euphorbiaceae) possesses low bioavailability.