The Synergetic Effects of Nonpolar and Polar Protic Solvents on the Properties of Felodipine and Soluplus in Solutions, Casting Films, and Spray-Dried Solid Dispersions

Amorphous Solid Dispersion of Hesperidin with Polymer Excipients for Enhanced Apparent Solubility as a More Effective Approach to the Treatment of Civilization Diseases

The present study reports amorphous solid dispersions (ASDs) of hesperidin (Hes) prepared by ball milling to improve its solubility and apparent solubility over the unmodified compound. The carriers were Soluplus^® (Sol), alginate sodium (SA), and hydroxypropylmethylcellulose (HPMC). XRPD analysis confirmed full amorphization of all binary systems in 1:5 w/w ratio. One glass transition (T_g) observed in DSC thermograms of hesperidin:Soluplus^® (Hes:Sol) and hesperidin:HPMC (Hes:HPMC) 1:5 w/w systems confirmed complete miscibility. The mathematical model (Gordon-Taylor equation) indicates that the obtained amorphous systems are characterized by weak interactions. The FT-IR results confirmed that hydrogen bonds are responsible for stabilizing the amorphous state of Hes. Stability studies indicate that the strength of these bonds is insufficient to maintain the amorphous state of Hes under stress conditions (25 °C and 60 °C 76.4% RH). HPLC analysis suggested that the absence of degradation products indicates safe hesperidin delivery systems. The solubility and apparent solubility were increased in all media (water, phosphate buffer pH 6.8 and HCl (0.1 N)) compared to the pure compound. Our study showed that all obtained ASDs are promising systems for Hes delivery, wherein Hes:Sol 1:5 w/w has the best solubility (about 300-fold in each media) and apparent solubility (about 70% in phosphate buffer pH 6.8 and 63% in HCl).

Development and Characterization of Eudragit® EPO-Based Solid Dispersion of Rosuvastatin Calcium to Foresee the Impact on Solubility, Dissolution and Antihyperlipidemic Activity

Poor solubility is the major challenge involved in the formulation development of new chemical entities (NCEs), as more than 40% of NCEs are practically insoluble in water. Solid dispersion (SD) is a promising technology for improving dissolution and, thereby, the bioavailability of poorly soluble drugs. This study investigates the influence of a pH-sensitive acrylate polymer, EPO, on the physicochemical properties of rosuvastatin calcium, an antihyperlipidemic drug. In silico docking was conducted with numerous polymers to predict drug polymer miscibility. The screened-out polymer was used to fabricate the binary SD of RoC in variable ratios using the co-grinding and solvent evaporation methods. The prepared formulations were assessed for physiochemical parameters such as saturation solubility, drug content and in vitro drug release. The optimized formulations were further ruled out using solid-state characterization (FTIR, DSC, XRD and SEM) and in vitro cytotoxicity. The results revealed that all SDs profoundly increased solubility as well as drug release. However, the formulation RSE-2, with a remarkable 71.88-fold increase in solubility, presented 92% of drug release in the initial 5 min. The molecular interaction studied using FTIR, XRD, DSC and SEM analysis evidenced the improvement of in vitro dissolution. The enhancement in solubility of RoC may be important for the modulation of the dyslipidemia response. Therefore, pharmacodynamic activity was conducted for optimized formulations. Our findings suggested an ameliorative effect of RSE-2 in dyslipidemia and its associated complications. Moreover, RSE-2 exhibited nonexistence of cytotoxicity against human liver cell lines. Convincingly, this study demonstrates that SD of RoC can be successfully fabricated by EPO, and have all the characteristics that are favourable for superior dissolution and better therapeutic response to the drug.

Analytical and Computational Methods for the Determination of Drug-Polymer Solubility and Miscibility

In the pharmaceutical industry, poorly water-soluble drugs require enabling technologies to increase apparent solubility in the biological environment. Amorphous solid dispersion (ASD) has emerged as an attractive strategy that has been used to market more than 20 oral pharmaceutical products. The amorphous form is inherently unstable and exhibits phase separation and crystallization during shelf life storage. Polymers stabilize the amorphous drug by antiplasticization, reducing molecular mobility, reducing chemical potential of drug, and increasing glass transition temperature in ASD. Here, drug-polymer miscibility is an important contributor to the physical stability of ASDs. The current Review discusses the basics of drug-polymer interactions with the major focus on the methods for the evaluation of solubility and miscibility of the drug in the polymer. Methods for the evaluation of drug-polymer solubility and miscibility have been classified as thermal, spectroscopic, microscopic, solid-liquid equilibrium-based, rheological, and computational methods. Thermal methods have been commonly used to determine the solubility of the drug in the polymer, while other methods provide qualitative information about drug-polymer miscibility. Despite advancements, the majority of these methods are still inadequate to provide the value of drug-polymer miscibility at room temperature. There is still a need for methods that can accurately determine drug-polymer miscibility at pharmaceutically relevant temperatures.

Effect of solvents and cellulosic polymers on quality attributes of films loaded with a poorly water-soluble drug

The combined effect of solvent, cellulosic polymer, and a poorly water-soluble drug, fenofibrate (FNB) on solution-cast pharmaceutical film quality attributes, e.g., morphology, drug recrystallization, content uniformity, mechanical properties, dissolution rate and supersaturation level, was investigated. Film morphology, content uniformity, and mechanical properties were impacted by the extent of FNB recrystallization which was strongly affected by FNB solubility in the solvent as compared to the polymer type, hydroxypropyl methylcellulose or hydroxypropyl cellulose. FNB recrystallization affected drug dissolution rates and supersaturation under non-sink conditions. Specifically, the area under the curve linearly correlated with recrystallization. After one-year storage, FNB recrystallization reached very high levels even for the films with no initial recrystallization, suggesting low initial crystallinity does not guarantee stability. Thus, uncontrolled recrystallization and poor time-stability would be unavoidable for solution-cast films. Overall, both the polymer and the solvent strongly impact drug recrystallization, film structure, mechanical properties, dissolution rate, and supersaturation.

Bile acid transporter mediated STC/Soluplus self-assembled hybrid nanoparticles for enhancing the oral drug bioavailability

The nano-particulate system for oral delivery faces a big challenge across the gastrointestinal bio-barriers. The aim was to explore the potential applications of bile acid transporter mediated the self-assembled hybrid nanoparticles (SHNPs) of sodium taurocholate (STC) and polyvinyl caprolactam-polyvinyl acetate-polyethylene glycol (Soluplus) for augmenting the oral delivery of poorly water-soluble drugs. Felodipine (FLDP) was chosen as a model drug. The self-assembly of STC with Soluplus to load FLDP and the microstructure of the SHNPs were confirmed using molecular simulation, STC determination by high performance liquid chromatography (HPLC) and transmission electron microscope. Results showed that STC was integrated with Soluplus on the surface of nanoparticles by hydrophobic interactions. The permeability of FLDP loaded STC/Soluplus SHNPs was STC dependent in the ileum, which was inhibited by the higher concentrations of STC and the inhibitor of apical sodium-dependent bile acid transporter (ASBT). STC/Soluplus (1:9) SHNPs significantly improved the drug loading of FLDP, achieved the highest permeability of FLDP and realized 1.6-fold of the area under the curve (AUC) of Soluplus self-assembled nanoparticles (SNPs). A water-quenching fluorescent probe P4 was loaded into the STC/Soluplus SHNPs, which verified that the SHNPs were transferred intactly across the ileum. In conclusion, STC/Soluplus SHNPs via ASBT are a potential strategy for enhancing the oral bioavailability of poorly water-soluble drugs.

A Novel Micron-Size Particulate Formulation of Felodipine with Improved Release and Enhanced Oral Bioavailability Fabricated by Coaxial Electrospray

The antihypertensive drug felodipine (FD) is a typical biopharmaceutics classification system (BCS) II drug; thus, improving the dissolution rate of FD is very important to enhance its bioavailability. Besides, according to the in situ "close loop" perfusion assay, we found that the jejunum is the main absorptive site, then the duodenum and ileum. Consequently, a novel micron-size particulate of FD in a core-shell structure was fabricated by a coaxial electrospray technique; within the drug delivery system, Hypromellose K4M (HPMC K4M) was selected as a sheath material to prolong the retention time in the upper GI tract, while povidone K30 (PVP K30) was mixed with FD in the inner layer. The dissolution study in three different media (0.02% Tween-80 solution; phosphate buffer containing 0.02% Tween-80, pH 6.8; and HCl solution containing 0.02% Tween-80, pH 1.2) demonstrated that FD-loaded coaxial electrospray particles (F-COES) could greatly improve the dissolution of FD. Furthermore, in vivo pharmacokinetics revealed that F-COES emerged no changes in the half-life but significantly prolonged the t_max and increased the oral bioavailability. Collectively, this work supplies a promising drug release system that will improve the dissolution and enhance the bioavailability simultaneously for those poorly water-soluble drugs mainly absorbed in the upper GI tract.