Nanoporous Silica Entrapped Lipid-Drug Complexes for the Solubilization and Absorption Enhancement of Poorly Soluble Drugs

Redistribution of hydrophobic hypericin from nanoporous particles of SBA-15 silica in vitro, in cells and in vivo

Nanoporous silica is nowadays used in various fields of nano- and micro-materials research. The advantage of nanoporous material is that it can be filled with various hydrophilic and hydrophobic molecules, which are then delivered to the target cells and tissues. In the present study, we have studied the interaction of nanoporous silica with hydrophobic and photodynamically active molecule - hypericin. Hypericin was adsorbed on/in SBA-15 silica, which led to the disappearance of its fluorescence due to hypericin aggregate formation. However, it was observed here that hypericin can be easily redistributed from these particles towards proteins and lipids in serum and cells in vitro and in vivo. Moreover, the charged surface character of SBA-15 pores forced the creation of protein/lipid corona on particles. Such complex enabled monomerization of hypericin on the surface of particles presented by fluorescence in the corona and singlet oxygen production suitable for photodynamic therapy (PDT). The PDT efficacy achieved by introducing the new construct into the PDT protocol was comparable to the efficacy of hypericin PDT. In conclusion, this study demonstrates a promising approach for the delivery of hydrophobic photosensitizers to cancer cells by nanoporous silica using fluorescence techniques.

Development of Clinically Optimized Sitagliptin and Dapagliflozin Complex Tablets: Pre-Formulation, Formulation, and Human Bioequivalence Studies

The purpose of this study is to derive an optimal drug release formulation with human clinical bioequivalence in developing a sitagliptin phosphate monohydrate-dapagliflozin propanediol hydrate fixed-dose combination (FDC) tablet as a treatment for type 2 diabetes mellitus. As a treatment for type 2 diabetes mellitus, the combined prescription of dipeptidyl peptidase-4 (DPP-4) inhibitors and sodium-glucose cotransporter-2 (SGLT-2) inhibitors is common. Therefore, this study simplified the number of individual drugs taken and improved drug compliance by developing FDC tablets containing sitagliptin phosphate monohydrate as a DPP-4 inhibitor and dapagliflozin propanediol hydrate as an SGLT-2 inhibitor. To derive the optimal dosage form, we prepared single-layer tablets, double-layer tablets, and dry-coated tablets and evaluated the drug control release ability, tableting manufacturability, quality, and stability. Single-layer tablets caused problems with stability and drug dissolution patterns. When the dissolution test was performed on the dry-coated tablets, a corning effect occurred, and the core tablet did not completely disintegrate. However, in the quality evaluation of the double-layer tablets, the hardness was 12-14 kilopond, the friability was 0.2%, and the disintegration was within 3 min. In addition, the stability test revealed that the double-layer tablet was stable for 9 months under room temperature storage conditions and 6 months under accelerated storage conditions. In the drug release test, only the FDC double-layer tablet showed the optimal drug release pattern that satisfied each drug release rate. In addition, the FDC double-layer tablet showed a high dissolution rate of over 80% in the form of immediate-release tablets within 30 min in a pH 6.8 dissolution solution. In the human clinical trial, we co-administered a single dose of a sitagliptin phosphate monohydrate-dapagliflozin propanediol hydrate FDC double-layered tablet and the reference drug (Forxiga^®, Januvia^®) in healthy adult volunteers. This study showed clinically equivalent results in the stability and pharmacodynamic characteristics between the two groups.

In Vitro-In Vivo Correlation of Tianeptine Sodium Sustained-Release Dual-Layer Tablets

Tianeptine tablets are currently marketed to be designed for immediate-release tablets. The tianeptine has a short half-life, making it difficult to design for sustained-release tablets and achieve bioequivalence with the tianeptine immediate-release tablet (Stablon^®). We established the in vitro-in vivo correlation (IVIVC) of three formulations of tianeptine sustained-release tablets according to their granule size. To evaluate sustained drug release, in vitro tests were performed in pH 1.2 media for 24 h. In vivo pharmacokinetic analysis was performed following oral administration of reference drug and test drug to beagle dogs. The dissolution profile revealed delayed release as the size of the granules increased. The dissolution results were confirmed in pharmacokinetic analysis, showing that the half-life was delayed as granule size increased. The final formulation and reference drug showed an equivalent area under the curve (AUC). Through this, IVIVC was established according to the size of the tianeptine sodium granules, which is the purpose of this study, and was used to predict in vivo pharmacokinetics from the formulation composition. This approach may be useful for determining optimal formulation compositions to achieve the desired pharmacokinetics when developing new formulations.

Studies on Preformulation and Formulation of JIN-001 Liquisolid Tablet with Enhanced Solubility

This study aimed to develop a heat shock protein 90 (Hsp90) inhibitor liquisolid tablet with improved solubility to overcome low bioavailability issues. As an active pharmaceutical ingredient (API), JIN-001, a novel Hsp90 inhibitor, was reported to have substantial in vitro antiproliferative and in vivo antitumor activity; however, JIN-001 was a crystalline solid with very low solubility in an aqueous solution, and therefore, Capryol 90, which has excellent solubilization ability, was selected as an optimal liquid vehicle based on solubility studies. JIN-001 liquisolid (JLS) powder was successfully prepared by dissolving JIN-001 in Capryol 90 and mixing colloidal silicon dioxide (CSD) used as an oil adsorption agent. The prepared JLS was confirmed to be amorphous. Based on the result of the solubility test of JLS, compared to JIN-001, the solubility of the former was significantly improved in all solvents regardless of pH. JLS tablets were prepared through wet granulation using JIN-001 and stable excipients based on the compatibility test. The developed JLS tablet significantly increased the drug release rate in all tested solutions; however, the liquisolid method had no significant effect on bioavailability in the pharmacokinetics study in beagle dogs. In conclusion, the liquisolid system influenced the solubility and dissolution rate of JIN-001.

QbD Consideration for Developing a Double-Layered Tablet into a Single-Layered Tablet with Telmisartan and Amlodipine

The aim of this study was to develop a single-layered version of commercially available Twynstar^® (Telmisartan + Amlodipine) double-layered tablets to improve the dosing convenience. A quality-by-design approach was applied to develop the single-layered version. To evaluate the range and cause of risks for a single-layered tablet in the formulation design research, we used the tools of the risk assessment, initial risk assessment of preliminary hazard analysis and main risk assessment of failure mode and effect analysis to determine the parameters affecting formulation, drug dissolution, and impurities. The critical material attributes were the stabilizer and disintegrant, and the critical process parameters were the wet granulation and tableting process. The optimal range of the design space was determined using the central composite design in the wet granulation and tablet compression processes. The stabilizer, kneading time, and disintegrant of the wet granulation were identified as X values affecting Y values. The compression force and turret speed in the tablet compression were identified as X values affecting Y values. After deciding on the design space with the deduced Y values, the single-layered tablets were formulated, and their dissolution patterns were compared with that of the double-layered tablet. The selected quality-by-design (QbD) approach single-layered tablet formulated using design space were found to be bioequivalent to the Twynstar^® double-layered tablets. Hence, the development of single-layered tablets with two API using the QbD approach could improve the medication compliance of patients and could be used as a platform to overcome time-consuming and excessive costs and the technical and commercial limitations related to various multi-layered tablets.

Formation of Self-Assembled Liquid Crystalline Nanoparticles and Absorption Enhancement of Ω-3s by Phospholipids and Oleic Acids

This study aimed to optimize and evaluate self-assembled liquid crystalline nanoparticles (SALCs) prepared from phospholipids and oleic acid for enhancing the absorption of Ω-3s. We explored the structure and optimal formulation of SALCs, which are composed of Ω-3 ethyl ester (Ω-3 EE), phospholipids, and oleic acid, using a ternary diagram and evaluated the improvement in Ω-3 dissolution, permeation, and oral bioavailability. The in vitro dissolution and pharmacokinetics of Ω-3 SALCs were compared with those of Omacor soft capsules (as the reference). The shape of the liquid crystal was determined according to the composition of phospholipids, oleic acids, and Ω-3s and was found to be in cubic, lamellar, and hexagonal forms. The dissolution rates of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) obtained from Ω-3 SALCs were 1.7 to 2.3-fold higher than those of the Omacor soft capsules. Furthermore, a pharmacokinetic study in male beagle dogs revealed that Ω-3 SALCs increased the oral bioavailability of Ω-3 EE by 2.5-fold for EPA and 3.1-fold for DHA compared with the reference. We found an optimal formulation that spontaneously forms liquid crystal-based nanoparticles, improving the bioavailability of EPA and DHA, not found in the existing literature. Our findings offer insight into the impact of nanoparticle phase on the oral delivery of oil-soluble drugs and provide a novel Ω-3 EE formulation that improves the bioavailability of EPA and DHA.

New Peceol™/Span™ 60 Niosomes Coated with Chitosan for Candesartan Cilexetil: Perspective Increase in Absolute Bioavailability in Rats

PURPOSE

Candesartan cilexetil (CC), a prodrug of candesartan (CDT), is a class II BCS drug that suffers from poor oral bioavailability because of low aqueous solubility, P-gp efflux and first-pass metabolism. The absolute bioavailability reported for CC was only 15% and the methods to increase it remain elusive, thus the aim of our work was to prepare new CC-loaded niosomes encompassing, for the first time, glycerol monooleate GMO (Peceol™), as P-gp efflux inhibitor and promoter of lymphatic transport with Span™ 60 as bioenhancer. The prepared niosomes were further coated with chitosan for augmenting the CC oral absorption.

METHODS

The niosomes were prepared by thin film hydration method through quality by design approach, using two levels of each of three critical process parameters (CPPs), namely, XA (the molar ratio of surfactant mixture to cholesterol) at a ratio of 1:1 or 2:1; XB (the molar ratio of Span™ 60 to Peceol™) at a ratio of 1:1 or 2:1; and XC (the drug amount) at 15 mg or 30 mg. The investigated critical quality attributes (CQAs) were entrapment efficiency percent, particle size, and polydispersity index. The optimized uncoated and chitosan coated formulations were subjected to DSC and stability study. In vitro drug release, biocompatibility with Caco-2 cells and lastly the absolute bioavailability evaluation in rats were assessed.

RESULTS

The physical properties of the optimized and stable niosomes were satisfactory. The ingredients were compatible with each other and biocompatible with Caco-2 cells. The synergistic combination of Peceol™ and Span™ 60 probably surmounted the P-gp efflux with an increase in oral absolute bioavailability of niosomes to five times that of CC suspension.

CONCLUSION

The new niosomal formulations of CC containing Peceol™ with Span™ 60 and cholesterol either uncoated or coated with chitosan were a successful paradigm in achieving high oral absolute bioavailability and increased Caco-2 cells biocompatibility.