Improved Dissolution Properties of Co-amorphous Probucol with Atorvastatin Calcium Trihydrate Prepared by Spray-Drying

A co-amorphous model drug was prepared by the spray-drying (SD) of probucol (PC) and atorvastatin calcium trihydrate salt (ATO) as low water solubility and co-former components, respectively. The physicochemical properties of the prepared samples were characterized by powder X-ray diffraction (PXRD) analysis, thermal analysis, Fourier transform infrared spectroscopy (FTIR), and dissolution tests. Stability tests were also conducted under a stress environment of 40 °C and 75% relative humidity. The results of PXRD measurements and thermal analysis suggested that PC and ATO form a co-amorphous system by SD. Thermal analysis also indicated an endothermic peak that followed an exotherm in amorphous PC and a physical mixture (PM) of amorphous PC and ATO; however, no endothermic peak was detected in the co-amorphous system. The dissolution profiles for PC in the co-amorphous sample composed of PC and ATO were improved compared to those for raw PC crystals or the PM. Stability tests indicated that the co-amorphous material formed by PC and ATO can be stored for 35 d without crystallization, whereas amorphous PC became crystallized within a day. Therefore, co-amorphization of PC and ATO prepared by SD is considered to be a useful method to improve the solubility of PC in water.

Bio Micro-Nano Technologies of Antioxidants Optimised Their Pharmacological and Cellular Effects, ex vivo, in Pancreatic β-Cells

Introduction

Recent formulation and microencapsulation studies of probucol (PB) using the polymer sodium alginate (SA) and bile acids have shown promising results but PB stability, and pharmacology profiles remain suboptimal. This study aimed to investigate novel polymers for the nano and micro encapsulation of PB, with the anti-inflammatory bile acid ursodeoxycholic acid (UDCA).

Material and methods

Six formulations using three types of polymers were investigated with and without UDCA. The polymers were NM30D, RL30D, and RS30D and they were mixed with SA and PB at set ratios and microencapsulated using oscillating-voltage-mediated nozzle technology coupled with ionic gelation. The microcapsules were examined for physical and biological effects using pancreatic β-cells.

Results and discussion

UDCA addition did not adversely affect the morphology and physical features of the microcapsules. Despite thermal stability remaining unchanged, bile acid incorporation did enhance the electrokinetic stability of the formulation system for NM30D and RL30D polymers. Mechanical stability remained similar in all groups. Enhanced uptake of PB from the microcapsule by pancreatic β-cells was only seen with NM30D-UDCA-intercalated microcapsules and this effect was sustained at both glucose levels of 5.5 and 35.5 mM.

Conclusion

UDCA addition enhanced PB delivery and biological effects in a formulation-dependent manner.

Improved dissolution and oral absorption by co-grinding active drug probucol and ternary stabilizers mixtures with planetary beads-milling method

The objective of this work is to construct a nanosuspension drug delivery system of probucol, a BCS II drug, in order to improve its dissolution and oral bioavailability. The wet milling procedure using planetary beads-milling equipment was utilized to grind the raw probucol to ultrafine nanoparticle/nanocrystal aqueous suspension that was further solidified by freeze-drying process. Cellulose derivatives of different substitution groups and molecular weights, including HPMC, HPC, and MC, were evaluated as the primary stabilizer of probucol nanosuspension. Ternary stabilizers system composed of a primary stabilizer (cellulose derivative, i.e. HPC), a nonionic surfactant (Pluronic® F68), and an anionic surfactant (SDS) was employed to obtain probucol nanosuspension of finer particle size and enhanced dissolution in aqueous media. The probucol nanosuspension with good physical stability showed no obvious change of particle size even after storing over 7 d at 4 °C or 25 °C. The solidified probucol nanosuspension with trehalose as the cryoprotectant showed the highest dissolution rate (> 60% at 2 h) compared to other cryoprotectant. The in vivo pharmacokinetic evaluation indicated about 15-folds higher AUC value of the probucol nanosuspension compared to that of coarse probucol suspension after oral administration to rats. The probucol nanosuspension prepared by wet-milling and ternary stabilizers system may find wide applications for improving the dissolution and oral absorption of water-insoluble drugs.

Preparation and Evaluation of Probucol-Phospholipid Complex with Enhanced Bioavailability and No Food Effect

To enhance the oral bioavailability and eliminate the food effect of probucol. Probucol-phospholipid complex was prepared using solvent-evaporation method in this research. Several methods were used to validate the formation of complexes, such as FT-IR, SEM, DSC and PXRD, and the solubility of PRO and PRO-PLC was detected by HPLC. Pharmacokinetic testing was conducted in the fasted and fed state. FTIR, SEM, DSC and PXRD validated the existence of PRO-PLC. The solubility of PRO in complexes was 15.05 μg/mL, which was 215-fold of the PRO-API. The dissolution rate was increased by preparing PRO-PLC. Compared with commercial tablets, the PRO-PLC complexes exhibited higher peak plasma concentration (1.69 ± 0.44 μg/mL), increased AUC_0-24 h (6.8 ± 1.3 μg/mL h), which mean the bioavailability of PRO was increased. In addition, the absorption of PRO was not interfered with food. In conclusion, an improved solubility and bioavailability was achieved with the preparation of PRO-PLC. Additionally, the dissolution behaviour was good and the food effect was eliminated.

Improved oral bioavailability of 20(R)-25-methoxyl-dammarane-3β, 12β, 20-triol using nanoemulsion based on phospholipid complex: design, characterization, and in vivo pharmacokinetics in rats

The aim of the study was to improve the oral absorption of the compound 25-OCH3-PPD with poor hydrophilicity and lipophilicity. 25-OCH3-PPD-phospholipid complex was prepared by solvent evaporation, then characterized by differential scanning calorimetry, scanning electron microscopy, and infrared absorption spectroscopy. The aqueous solubility and oil-water partition coefficient were compared with the free compound. A nanoemulsion loaded with 25-OCH3-PPD-phospholipid complex was developed by dissolving the complex in water in the presence of hydrophilic surfactant under sonication. After oral administration of the nanoemulsion and the suspension of 25-OCH3-PPD in rats, the concentrations of 25-OCH3-PPD in plasma were determined by high-performance liquid chromatography-tandem mass spectrometry method. The results showed that the solubility of the complex in water and n-octanol was enhanced. The oil-water partition coefficient improved 1.7 times. Peak plasma concentration and area under the curve(0-24 h) of the nanoemulsion of 25-OCH3-PPD-phospholipid complex were higher than that of free compound by 3.9- and 3.5-folds.

Hunter screening design to understand the product variability of solid dispersion formulation of a peptide antibiotic

The focus of present research was to understand and control the variability of solid dispersion (SD) formulation of non-ribosomal peptide antibiotic, vancomycin (VCM). Hunter screening design was constructed using seven independent variables namely melting temperature (X1), congealing temperature (X2), mixing time (X3), type of capsule shell (X4), filling method (X5), molecular weight of polyethylene glycol (PEG, X6) and surfactant type (X7), and responses measured were cumulative percentage of VCM released in 45 min (Y1) and potency (Y2). The SD formulations were prepared by melt-fusion method, and tested for dissolution, potency, and characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), powder X-ray diffraction (PXRD) and near infrared chemical imaging (NIR-CI). Statistically significant (p<0.05) effect of congealing temperature (X2), type of capsule shell (X4), filling method (X5), molecular weight of PEG (X6) was revealed on Y1, and R(2) of 0.992 was obtained between experimental and predicted value. None of the factors have statistically significant (p>0.05) influence on Y2. SEM, DSC and PXRD indicated crystalline nature of SD formulations. Homogeneity of SD formulations was shown by NIR-CI images. In summary, the quality of VCM SD formulations could be assured by controlling the critical factors during manufacturing.