The potential of synergism between ultrasonic energy and Soluplus ® as a tool for solubilization and dissolution enhancement of a poorly water soluble drug. A statistically based process optimization

Development of eplerenone nano sono-crystals using factorial design: enhanced solubility and dissolution rate via anti solvent crystallization technique

OBJECTIVE

The purpose of this work was to improve EP solubility by using a sono-crystalization approach to reduce particle size and hence, increase the dissolution rate. Significance Eplerenone (EP) is an antagonist of the aldosterone receptor and is used for the treatment of hypertension and chronic heart failure. EP was classed as biopharmaceutical classification (BCS) class II because of its poor solubility and high permeability, which retards dissolution rate and drug absorption, and decreases bioavailability.

METHODS

Three-factors and two-level (2³) multifactorial design have been employed to study the effect of independent variables which are drug concentration; (X1), stabilizer type (X2), and stabilizer concentration (X3) on responses; saturated solubility of EP in distilled water (Y1), saturated solubility in acidic media pH 1.2 (Y2), particle size (Y3), and polydispersity index, PDI (Y4). Also, they were characterized by Fourier transformed infrared spectroscopy (FTIR), Powder X-ray diffraction (PXRD), Differential scanning calorimetry (DSC), and yield percentage. The optimum formula was further subjected to an in-vitro release study.

RESULTS

The optimized formulation showed a saturated solubility of EP as 1.29, and 1.86 (mg/ml) in distilled water and acidic media (pH 1.2) respectively. Also, the particle size of 133 nm, and PDI of 0.824 with a small percentage of the difference between the observed and predicted values. Ninety-one percent of EP was released within 10 min., and it was completely released within 45 min. with a significantly higher release rate compared to raw drug.

CONCLUSION

This work resulted in a satisfactory enhancement of solubility and dissolution rate which, is suitable for further in-vivo analysis.

Preparation of solid dispersion systems for enhanced dissolution of poorly water soluble diacerein: In-vitro evaluation, optimization and physiologically based pharmacokinetic modeling

Diacerein (DCN), a BCS II compound, suffers from poor aqueous solubility and limited bioavailability. Solid dispersion systems (SD) of DCN were prepared by solvent evaporation, using hydrophilic polymers. In-vitro dissolution studies were performed and dissolution parameters were evaluated. I-Optimal factorial design was employed to study the effect of formulation variables (drug:polymer ratio and polymer type) on the measured responses including; drug content (DC) (%), dissolution efficiency at 15 min (DE _{(15 min)}%) and 60 min (DE _{(60 min)}%) and mean dissolution time (MDT) (min). The optimized SD was selected, prepared and evaluated, allowing 10.83 and 3.42 fold increase in DE _{(15 min)}%, DE _{(60 min)}%, respectively and 6.07 decrease in MDT, compared to plain drug. DSC, XRD analysis and SEM micrographs confirmed complete amorphization of DCN within the optimized SD. Physiologically based pharmacokinetic (PBPK) modeling was employed to predict PK parameters of DCN in middle aged healthy adults and geriatrics. Simcyp^® software established in-vivo plasma concentration time curves of the optimized SD, compared to plain DCN. Relative bioavailability of the optimized SD compared to plain drug was 229.52% and 262.02% in healthy adults and geriatrics, respectively. Our study reports the utility of PBPK modeling for formulation development of BCS II APIs, via predicting their oral bio-performance.

Development of orally disintegrating tablets containing solid dispersion of a poorly soluble drug for enhanced dissolution: In-vitro optimization/in-vivo evaluation

Diacerein (DCN), a potent anti-inflammatory API used to treat osteoarthritis yet, it suffers from poor water solubility which affects its oral absorption. Unabsorbed colonic DCN is converted into rhein, which is responsible for laxation as a main side effect of DCN treatment. Therefore, in this study orally disintegrating tablets (ODTs) loaded with optimized DCN solid dispersion system were prepared using different co-processed excipients (Prosolv^® ODT, Pharmaburst^® 500 and F-melt^®), aiming to achieve improved solubility, rapid absorption and consequently limited amount of rhein reaching the colon. Prepared ODTs were evaluated for physical characteristics, in-vitro drug release, disintegration and wetting times. Dissolution parameters; dissolution efficiency percent at 10 (DE _{(10 min)}%) and 30 (DE _{(30 min)}%) min and mean dissolution time (MDT) were determined. The optimized ODT showed 1.50 and 1.12 fold increase in DE _{(10 min)}% and DE _{(30 min)}%, respectively and 2 fold decrease in MDT, compared to Diacerein^® capsules. In-vivo anti-inflammatory effect of optimized ODT, using rat paw edema revealed significant increase in edema inhibition (p < 0.0465) and promoted onset of action compared to Diacerein^® capsules at 0.5 hr. It could be concluded that optimized ODT could be promising for enhanced dissolution and rapid absorption of DCN from the oral cavity.