Utilization of a fattigation platform gelatin-oleic acid sodium salt conjugate as a novel solubilizing adjuvant for poorly water-soluble drugs via self-assembly and nanonization

Self-assembled nanonization of fatty acid-conjugated vaccine antigen for enhanced thermal stability

The aim of this study was to evaluate the enhanced thermal stability and physicochemical properties of fattigated vaccine antigens. High molecular weight influenza hemagglutinin (Heg) was used as a model antigen because of low heat stability requiring cold chamber. Heg was conjugated with long-chain oleic acid (C18) and short-chain 3-decenoic acid (C10) to prepare fattigated Heg. Circular dichroism analysis revealed no significant changes in the three-dimensional structure post-conjugation. In the liquid state, the fattigated Heg was self-assembled into nanoparticles (NPs) due to its amphiphilic nature, with sizes of 136.27 ± 12.78 nm for oleic acid-conjugated Heg (HOC) and 88.73 ± 3.27 nm for 3-decenoic acid-conjugated Heg (HDC). Accelerated thermal stability studies at 60 °C for 7 days demonstrated that fattigated Heg exhibited higher thermal stability than Heg in various liquid or solid states. The longer-chained HOC showed better thermal stability than HDC in the liquid state, attributed to increased hydrophobic interactions during self-assembly. In bio-mimicking liquid states at 37 °C, HOC exhibited higher thermal stability than Heg. Furthermore, solid-state HOC with cryoprotectants (trehalose, mannitol, and Tween® 80) had significantly increased thermal stability due to reduced exposure of protein surface area via nanonization behavior. The current fattigation platform could be a promising strategy for developing thermostable nano vaccines of heat-labile vaccine antigens.

Investigation of Cannabinoid Acid/Cyclodextrin Inclusion Complex for Improving Physicochemical and Biological Performance

This study aimed to investigate the enhancement of cannabinoid acid solubility and stability through the formation of a cannabinoid acid/cyclodextrin (CD) inclusion complex. Two cannabinoid acids, tetrahydro-cannabinolic acid (THCA) and cannabidiolic acid (CBDA), were selected as a model drug along with five types of CD: α-cyclodextrin (α-CD), β-cyclodextrin (β-CD), γ-cyclodextrin (γ-CD), hydroxypropyl-β-cyclodextrin (HP-β-CD), and methylated-β-cyclodextrin (M-β-CD). Phase solubility studies were conducted using various types of CD to determine the complex stoichiometry. The preparation methods of the CD inclusion complex were optimized by adjusting the loading pH solution and the drying processes (spray-drying, freeze-drying, spray-freeze-drying). The drying process of the cannabinoid acid/M-β-CD inclusion complex was further optimized through the spray-freeze-drying method. These CD complexes were characterized using solubility determination, differential scanning calorimetry (DSC), field-emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), and 1H NMR spectroscopy. DSC, XRD, and FE-SEM studies confirmed the non-crystalline state of the cannabinoid acid/CD inclusion complex. The permeation of THCA or CBDA from the M-β-CD spray-freeze-dried inclusion complex was highly improved compared to those of cannabis ethanolic extracts under simulated physiological conditions. The stability of the cannabinoid acid/M-β-CD inclusion complex was maintained for 7 days in a simulated physiological condition. Furthermore, the minimum inhibitory concentration of cannabinoid acid/M-β-CD inclusion complex had superior anti-cancer activity in MCF-7 breast cancer cell lines compared to cannabinoid acid alone. The improved physicochemical and biological performances indicated that these CD inclusion complexes could provide a promising option for loading lipophilic cannabinoids in cannabis-derived drug products.

A Novel Semi-Solid Self-Emulsifying Formulation of Aprepitant for Oral Delivery: An In Vitro Evaluation

Aprepitant is the first member of a relatively new antiemetic drug class called NK₁ receptor antagonists. It is commonly prescribed to prevent chemotherapy-induced nausea and vomiting. Although it is included in many treatment guidelines, its poor solubility causes bioavailability issues. A particle size reduction technique was used in the commercial formulation to overcome low bioavailability. Production with this method consists of many successive steps that cause the cost of the drug to increase. This study aims to develop an alternative, cost-effective formulation to the existing nanocrystal form. We designed a self-emulsifying formulation that can be filled into capsules in a melted state and then solidified at room temperature. Solidification was achieved by using surfactants with a melting temperature above room temperature. Various polymers have also been tested to maintain the supersaturated state of the drug. The optimized formulation consists of Capryol^TM 90, Kolliphor^® CS20, Transcutol^® P, and Soluplus^®; it was characterized by DLS, FTIR, DSC, and XRPD techniques. A lipolysis test was conducted to predict the digestion performance of formulations in the gastrointestinal system. Dissolution studies showed an increased dissolution rate of the drug. Finally, the cytotoxicity of the formulation was tested in the Caco-2 cell line. According to the results, a formulation with improved solubility and low toxicity was obtained.

Improving solubility of poorly water-soluble drugs by protein-based strategy: A review

Poorly water-soluble drugs are frequently encountered and present a most challengeable difficulty in pharmaceutical development. Poor solubility of drugs can lead to suboptimal bioavailability and therapeutic efficiency. Increasing efforts have been contributed to improve the solubility of poorly water-soluble drugs for better pharmacokinetics and pharmacodynamics. Among various solubility enhancement technologies, protein-based strategy to address poorly water-soluble drugs issues has special interests for natural advantages including versatile interactions between proteins and hydrophobic drugs, biocompatibility, biodegradation, and metabolization of proteins. The protein-drug formulations could be formed by covalent conjugations or noncovalent interactions to facilitate solubility of poorly water-soluble drugs. This review is to summarize the advances using proteins including plant proteins, mammalian proteins, and recombinant proteins, to enhance water solubility of poorly water-soluble drugs.

Prostate-specific membrane antigen targeted, glutathione-sensitive nanoparticles loaded with docetaxel and enzalutamide for the delivery to prostate cancer

Prostate cancer (PCa) is the most common malignant tumor in men. Chemotherapy with docetaxel (DTX) and novel hormonal agents such as enzalutamide (EZL) and abiraterone are the preferred first-line therapeutic regimens. Prostate-specific membrane antigen (PSMA) is overexpressed on the surface of PCa cells. This study aimed to prepare a PSMA targeted (Glutamate-Urea-Lysine, GUL ligand modified), glutathione (GSH)-sensitive (Cystamine, SS), DTX and EZL co-loaded nanoparticles (GUL-SS DTX/EZL-NPs) to treat PCa. Polyethylene glycol (PEG) was conjugated with oleic acid (OA) using a GSH-sensitive ligand: cystamine (PEG-SS-OA). GUL was covalently coupled to PEG-SS-OA to achieve GUL-PEG-SS-OA. GUL-PEG-SS-OA was used to prepare GUL-SS DTX/EZL-NPs. To evaluate the in vitro and in vivo efficiency of the system, human prostate cancer cell lines and PCa cells bearing mice were applied. Single drug-loaded nanoparticle and free drugs systems were utilized for the comparison of the anticancer ability. GUL-SS DTX/EZL-NPs showed a size of 143.7 ± 4.1 nm, with a PDI of 0.162 ± 0.037 and a zeta potential of +29.1 ± 2.4 mV. GUL-SS DTX/EZL-NPs showed high cancer cell uptake of about 70%, as well as higher cell growth inhibition efficiency (a maximum 79% of cells were inhibited after treatment) than single drug-loaded NPs and free drugs. GUL-SS DTX/EZL-NPs showed the most prominent tumor inhibition ability and less systemic toxicity. The novel GUL-SS DTX/EZL-NPs could be used as a promising system for PCa therapy.

Hydroxyl Group-Targeted Conjugate and Its Self-Assembled Nanoparticle of Peptide Drug: Effect of Degree of Saturation of Fatty Acids and Modification of Physicochemical Properties

Purpose

To conjugate different degree of saturation of C18 fatty acids (stearic acid, oleic acid, and linoleic acid) with the hydroxyl groups of leuprolide acetate (LEU acetate) and to investigate the controlled release and enhanced permeability through self-assembled nanoparticles (L18FNs).

Methods

Yamaguchi esterification with benzoyl chloride and DMAP (4-Dimethylaminopyridine) allowed the conjugation of the fatty acid to the hydroxyl group of LEU. The three conjugates were then designated as stearic acid-conjugated LEU, LSC, oleic acid-conjugated LEU, LOC, and linoleic acid-conjugated LEU, LLC, respectively. The conjugates (L18FCs) were purified using preparative HPLC (Prep-HPLC) and identified through various instrumental analyses.

Results

The zeta potential, particle size, and morphology of each L18FNs were evaluated. In the case of LSNs, the zeta potential value was relatively low and the particle size was larger than LONs and LLNs owing to the higher hydrophobicity of saturated fatty chain, while the LLNs showed a higher zeta potential and smaller particle size. In human plasma, LLC showed the fastest degradation rate with the highest accumulative drug release. The permeability of L18FNs was analyzed through the Franz diffusion cell experiment, confirming that the degree of saturation of fatty acids affects the permeability of LFNs. While the permeability of LSNs was not significantly enhanced due to higher particle size after nanonization, LONs and LLNs increased 1.56 and 1.85 times in permeation, respectively, compared to LEU.

Conclusion

Utilization of different degree of saturation of fatty acids to conjugate a peptide drug could provide pharmaceutical versatility via self-assembly and modification of physicochemical properties.

Electrostatic molecular effect of differently charged surfactants on the solubilization capacity and physicochemical properties of salt-caged nanosuspensions containing pH-dependent and poorly water-soluble rebamipide

In this study, the electrostatic molecular effect of differently charged surfactants on the solubilization capacity and physicochemical properties of salt-caged nanosuspensions (NSPs) containing poorly water-soluble drug was investigated. Anionic rebamipide (RBM) was chosen as a model drug because of its poor water solubility in low pH condition and ionizable acidic forms. Negatively charged sodium lauryl sulfate (SLS) and positively charged cetyltrimethylammonium bromide (CTAB) were selected as surfactants for the preparation of NSPs or in the dissolution medium. Salt-caged NSPs surrounded by NaCl were prepared by the HCl-NaOH neutralization method in the presence of poloxamer 407. Interestingly, the addition of positively charged CTAB in the preparation process or the dissolution media could interfere with the solubilization capacity of salt-caged NSPs containing a negatively charged drug via intermolecular electrostatic attraction. In the presence of positively charged CTAB, the salt-caged NSP was disordered in structure via electrostatic attractive interaction with partially ionizable anionic RBM resulting in changes in the physicochemical properties of the salt-caged NSP such as low drug content, increased particle size, decreased dissolution rate, and the formation of water-insoluble precipitates with rough and irregular crystals. This inhibitory effect of CTAB on the dissolution rate of pure RBM and the salt-caged NSP in pH 6.8 intestinal fluid was pronounced in a concentration-dependent manner mainly owing to the formation of precipitates, so-called poorly soluble complexes. When the salt-caged NSP (F1) was dissolved in DW containing CTAB, the dissolution rate decreased more significantly, dissolving less than 20% within 2 h. Depending on the surfactant charges, the charge density and the initial potential were varied during the dissolution of NSPs in deionized water (DW). In contrast, the negatively charged SLS did not significantly change the physicochemical properties of the salt-caged NSP. For example, the dissolution rate of the salt-caged NSP containing SLS in DW or pH 1.2 gastric fluid remained over 90% for 2 h. Surfactants for the formulation or dissolution media should be chosen carefully because of their effect on the physicochemical properties and solubilization capacity of salt-caged NSPs containing poorly water-soluble and ionizable drugs via electrostatic molecular interactions.

Antifungal Drugs TDM: Trends and Update

PURPOSE

The increasing burden of invasive fungal infections results in growing challenges to antifungal (AF) therapeutic drug monitoring (TDM). This review aims to provide an overview of recent advances in AF TDM.

METHODS

We conducted a PubMed search for articles during 2016-2020 using "TDM" or "pharmacokinetics" or "drug-drug-interaction" with "antifungal," consolidated for each AF. Selection was limited to English language articles with human data on drug exposure.

RESULTS

More than 1000 articles matched the search terms. We selected 566 publications. The latest findings tend to confirm previous observations in real-life clinical settings. The pharmacokinetic variability related to special populations is not specific but must be considered. AF benefit-to-risk ratio, drug-drug interaction (DDI) profiles, and minimal inhibitory concentrations for pathogens must be known to manage at-risk situations and patients. Itraconazole has replaced ketoconazole in healthy volunteers DDI studies. Physiologically based pharmacokinetic modeling is widely used to assess metabolic azole DDI. AF prophylactic use was studied more for Aspergillus spp. and Mucorales in oncohematology and solid organ transplantation than for Candida (already studied). Emergence of central nervous system infection and severe infections in immunocompetent individuals both merit special attention. TDM is more challenging for azoles than amphotericin B and echinocandins. Fewer TDM requirements exist for fluconazole and isavuconazole (ISZ); however, ISZ is frequently used in clinical situations in which TDM is recommended. Voriconazole remains the most challenging of the AF, with toxicity limiting high-dose treatments. Moreover, alternative treatments (posaconazole tablets, ISZ) are now available.

CONCLUSIONS

TDM seems to be crucial for curative and/or long-term maintenance treatment in highly variable patients. TDM poses fewer cost issues than the drugs themselves or subsequent treatment issues. The integration of clinical pharmacology into multidisciplinary management is now increasingly seen as a part of patient care.

In Vitro Evaluation of a Solid Supersaturated Self Nanoemulsifying Drug Delivery System (Super-SNEDDS) of Aprepitant for Enhanced Solubility

Aprepitant (APR) belongs to Class II of the Biopharmaceutical Classification System (BCS) because of its low aqueous solubility. The objective of the current work is to develop self-nanoemulsifying drug delivery systems (SNEDDS) of APR to enhance its aqueous solubility. Preformulation studies involving screening of excipients for solubility and emulsification efficiency were carried out. Pseudo ternary phase diagrams were constructed with blends of oil (Imwitor^® 988), cosolvent (Transcutol^® P), and various surfactants (Kolliphor^® RH40, Kolliphor^® ELP, Kolliphor^® HS15). The prepared SNEDDS were characterized for droplet size and nanoemulsion stability after dilution. Supersaturated SNEDDS (super-SNEDDS) were prepared to increase the quantity of loaded APR into the formulations. HPMC, PVP, PVP/VA, and Soluplus^® were used as polymeric precipitation inhibitors (PPI). PPIs were added to the formulations at 5% and 10% by weight. The influence of the PPIs on drug precipitation was investigated. In vitro lipolysis test was carried out to simulate digestion of formulations in the gastrointestinal tract. Optimized super-SNEDDS were formulated into free-flowing granules by adsorption on the porous carriers such as Neusilin^® US2. In vitro dissolution studies of solid super-SNEDDS formulation revealed an increased dissolution rate of the drug due to enhanced solubility. Consequently, a formulation to improve the solubility and potentially bioavailability of the drug was developed.

Double-Controlled Release of Poorly Water-Soluble Paliperidone Palmitate from Self-Assembled Albumin-Oleic Acid Nanoparticles in PLGA in situ Forming Implant

Purpose

To investigate the effects of solvents on the formation of self-assembled nanonization of albumin-oleic acid conjugates (AOCs) using a solvent exchange mechanism for the construction of in situ forming implants (ISFI).

Methods

A poorly water-soluble drug, paliperidone palmitate (PPP), was chosen as the model drug. AOC was synthesized with the 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) reaction. Dichloromethane, tetrahydrofuran, ethanol, N-methyl-2-pyrrolidone, dimethyl sulfoxide, and deionized water were selected to investigate the formation of self-assembled AOC nanoparticles (AONs). The volume ratios of organic solvents against water could determine the miscibility, injectability, and in situ nanonizing capability without aggregation.

Results

As the polarity of the organic solvents increased, the AONs exhibited a spherical shape, and the larger the volume of the solvent, the smaller the size of the AONs. To use AOC in ISFI for controlled release of PPP, poly(d,l-lactide-co-glycolide) (PLGA) was combined with the AOC in 2 mL of N-methyl-2-pyrrolidone and water solution (1.8/0.2 ratio). The release rates of all formulations exhibited similar curve patterns overall but were more controlled in decreasing order as follows: AOC, PLGA, and AOC/PLGA for 14 days.

Conclusion

A combined formulation of AOC and PLGA was found to effectively control the initial burst release of the drug.

Shear Stress-Dependent Targeting Efficiency Using Self-Assembled Gelatin-Oleic Nanoparticles in a Biomimetic Microfluidic System

Cellular properties and microenvironments, as well as the characteristics of nanoparticles (NPs), affect the cellular uptake and cytotoxic effects of drug-loaded NPs. Since there is fluid flow in the human blood system, fluid flow also affects the drug delivery efficiency of NPs. This study aimed to evaluate the cellular behaviors of drug-loaded soft NPs on A549 cancer cells under different levels of shear stress (0.5, 5, and 50 dynes/cm²) in the biomimetic microfluidic system. The soft self-assembled NPs were formed by the gelatin-oleic conjugate (GOC). The poorly water-soluble coumarin-6 or paclitaxel (PTX) were used as model markers for encapsulation within self-assembled NPs (C-GONs or PTX-GONs, respectively). The cellular uptake of C-GONs was found to be improved with shear-stress dependence. The inhibitory concentration (IC₅₀) of PTX-GONs at 0.5, 5, and 50 dynes/cm² was 0.106 µg/mL, 0.108 µg/mL, and 0.091 µg/mL, respectively, as compared to 0.138 µg/mL in a static condition. The cell killing efficiency of PTX-GONs was increased in the highest shear stress of 50 dynes/cm² in the static condition, and other levels of shear stress in dynamic conditions.