Study of equilibrium solubility measurement by saturation shake-flask method using hydrochlorothiazide as model compound

Amelioration of tableting properties and dissolution rate of naproxen co-grinded with nicotinamide: preparation and characterization of co-grinded mixture

OBJECTIVE AND SIGNIFICANCE

Reducing the dimensions, when other additives are present, shows potential as a method to improve the dissolution and solubility of biopharmaceutical classification system class II drugs that have poor solubility. In this investigation, the process involved grinding naproxen with nicotinamide with the aim of improving solubility and the rate of dissolution.

METHODS

Naproxen was subjected to co-milling with urea, dimethylurea, and nicotinamide using a planetary ball mill for a duration of 90 min, maintaining a 1:1 molar ratio for the excipients (screening studies). The co-milled combinations, naproxen in its pure milled form, and a physical mixture were subjected to analysis using X-ray powder diffraction (XRPD), scanning electron microscopy (SEM), and solubility assessment. The mixture displaying the highest solubility (naproxen-nicotinamide) was chosen for further investigation, involving testing for intrinsic dissolution rate (IDR) and Fourier-transform infrared spectroscopy (FTIR) after co-milling for both 90 and 480 min.

RESULTS AND CONCLUSION

The co-milled combination, denoted as S-3b and consisting of the most substantial ratio of nicotinamide to naproxen at 1:3, subjected to 480 min of milling, exhibited a remarkable 45-fold increase in solubility and a 9-fold increase in IDR. XRPD analysis of the co-milled samples demonstrated no amorphization, while SEM images portrayed the aggregates of naproxen with nicotinamide. FTIR outcomes negate the presence of any chemical interactions between the components. The co-milled sample exhibiting the highest solubility and IDR was used to create a tablet, which was then subjected to comprehensive evaluation for standard attributes. The results revealed improved compressibility and dissolution properties.

Nutraceutically-enhanced oral delivery of vitamin D3 via Bio-SNEDDS: Demonstrating in vivo superiority over pediatric formulations

BACKGROUND

Vitamin D3 (VD3) deficiency among children in Saudi Arabia remains a pressing concern due to its poor bioavailability and the limitations of current pediatric formulations. To address this challenge, we developed a groundbreaking pediatric self-nanoemulsifying drug delivery system (Bio-SNEDDS) for VD3, fortified with black seed oil and moringa seed oil for dual therapeutic benefits. Through meticulous formulation optimization using ternary phase diagrams and comprehensive testing, our Bio-SNEDDS demonstrated exceptional performance.

METHODS

Bio-SNEDDS were manufactured by incorporating Black seed oil and moringa seed oil as bioactive nutraceutical excipients along with various cosurfactant and surfactants. Bio-SNEDDS were systematically optimized through ternary phase diagrams, visual tests, droplet size analysis, drug solubilization studies, dispersion assessments, and pharmacokinetic testing in rats compared to Vi-De 3®.

RESULTS

Pseudoternary phase diagrams identified oil blends producing large nanoemulsion regions optimal for SNEDDS formation. The optimized F1 Bio-SNEDDS showed a mean droplet diameter of 33.7 nm, solubilized 154.46 mg/g VD3 with no metabolite formation, and maintained >88% VD3 in solution during 24 h dispersion testing. Notably, in vivo pharmacokinetic evaluation at a high VD3 dose demonstrated an approximately two-fold greater relative bioavailability over Vi-De 3®, validating the superb oral delivery performance of Bio-SNEDDS even under challenging high-dose conditions.

CONCLUSIONS

The Bio-SNEDDS provides an effective VD3 delivery strategy with established in vivo superiority over marketed products, along with offering additional health benefits from the natural oils.

Evaluation of Silybin Nanoparticles against Liver Damage in Murine Schistosomiasis mansoni Infection

Silybin (SIB) is a hepatoprotective drug known for its poor oral bioavailability, attributed to its classification as a class IV drug with significant metabolism during the first-pass effect. This study explored the potential of solid lipid nanoparticles with (SLN-SIB-U) or without (SLN-SIB) ursodeoxycholic acid and polymeric nanoparticles (PN-SIB) as delivery systems for SIB. The efficacy of these nanosystems was assessed through in vitro studies using the GRX and Caco-2 cell lines for permeability and proliferation assays, respectively, as well as in vivo experiments employing a murine model of Schistosomiasis mansoni infection in BALB/c mice. The mean diameter and encapsulation efficiency of the nanosystems were as follows: SLN-SIB (252.8 ± 4.4 nm, 90.28 ± 2.2%), SLN-SIB-U (252.9 ± 14.4 nm, 77.05 ± 2.8%), and PN-SIB (241.8 ± 4.1 nm, 98.0 ± 0.2%). In the proliferation assay with the GRX cell line, SLN-SIB and SLN-SIB-U exhibited inhibitory effects of 43.09 ± 5.74% and 38.78 ± 3.78%, respectively, compared to PN-SIB, which showed no inhibitory effect. Moreover, SLN-SIB-U demonstrated a greater apparent permeability coefficient (25.82 ± 2.2) than PN-SIB (20.76 ± 0.1), which was twice as high as that of SLN-SIB (11.32 ± 4.6) and pure SIB (11.28 ± 0.2). These findings suggest that solid lipid nanosystems hold promise for further in vivo investigations. In the murine model of acute-phase Schistosomiasis mansoni infection, both SLN-SIB and SLN-SIB-U displayed hepatoprotective effects, as evidenced by lower alanine amino transferase values (22.89 ± 1.6 and 23.93 ± 2.4 U/L, respectively) than those in control groups I (29.55 ± 0.7 U/L) and I+SIB (34.29 ± 0.3 U/L). Among the prepared nanosystems, SLN-SIB-U emerges as a promising candidate for enhancing the pharmacokinetic properties of SIB.

In Vitro Drug Release Testing Method For Nepafenac Ophthalmic Suspension

In vitro release test (IVRT) method is important to monitor batch-to-batch quality variations during pharmaceutical manufacturing and also to show the pharmaceutical equivalence of a generic product with the innovator. To fulfil regulatory requirements for approval of a generic ophthalmic suspension product, in vitro release study is required. No compendial or non-compendial method is available for IVRT of nepafenac ophthalmic suspension. Current research is aimed to screen various approaches using different conventional and non-conventional instruments to suggest the most suitable technique appropriate for nepafenac ophthalmic suspension followed by optimization of method parameters and validation. The trials used the paddle apparatus (USP Type-2) with dialysis sacs, the flow-through cell apparatus (USP Type-4), the rotating bottle apparatus, and the Franz diffusion cell apparatus. With the USP Type-4 apparatus drug release was found to be ∼ 83% in the simulated tear fluid (STF) of pH 7.4 in 120 min that increased to ∼ 97% upon the addition of surfactant sodium lauryl sulfate (SLS). With USP Type-2 and Franz diffusion cell apparatus, the drug release was either slow or not reaching close to the complete release. Whereas, in the case of the rotating bottle apparatus, a burst release profile was observed. The estimation of the drug release was done by the HPLC method and all the method validation parameters like specificity, accuracy, linearity, and precision were found to be within acceptance criteria.

Homogeneous crystallization and buried interface passivation for perovskite tandem solar modules

Scalable fabrication of all-perovskite tandem solar cells is challenging because the narrow-bandgap subcells made of mixed lead-tin (Pb-Sn) perovskite films suffer from nonuniform crystallization and inferior buried perovskite interfaces. We used a dopant from Good's list of biochemical buffers, aminoacetamide hydrochloride, to homogenize perovskite crystallization and used it to extend the processing window for blade-coating Pb-Sn perovskite films and to selectively passivate defects at the buried perovskite interface. The resulting all-perovskite tandem solar module exhibited a certified power conversion efficiency of 24.5% with an aperture area of 20.25 square centimeters.

Targeted liposomes encapsulated iridium(III) compound greatly enhance anticancer efficacy and induce cell death via ferroptosis on HepG2 cells

In this study, ligands 2-phenyl-1H-imidazo[4,5-f][1,10]phenanthroline (PIP), 2-(2-nitrophenyl)-1H-imidazo[4,5-f][1,10]phenanthroline (NPIP), 2-(2-nitronaphthalen-1-yl)-1H-imidazo[4,5-f][1,10]phenanthroline (NNIP) and their iridium(III) metal compounds [Ir(ppy)2(PIP)](PF6) (ppy = 2-phenylpyridine, 1a), [Ir(ppy)2(NPIP)](PF6) (1b), [Ir(ppy)2(NNIP)](PF6) (1c) were designed and synthesized. The anti-cancer activities of 1a, 1b and 1c on BEL-7402, HepG2, SK-Hep1 and non-cancer LO2 were detected using MTT method. 1a shows moderate, 1b and 1c display low or no anti-cancer activities. To elevate the anti-cancer effectiveness, encapsulating the compounds 1a, 1b and 1c into the ordinary or targeted liposomes to produce 1alip, 1blip, 1clip, or targeted 1aTlip, 1bTlip and 1cTlip. The IC50 values of 1alip, 1blip, 1clip, 1aTlip, 1bTlip and 1cTlip against HepG2 cells are 7.9 ± 0.1, 8.6 ± 0.2, 16.9 ± 0.5, 5.9 ± 0.2, 7.3 ± 0.1 and 9.7 ± 0.7 μM, respectively. Specifically, the anti-tumor activity assays in vivo found that the inhibitory rates are 23.24 % for 1a, 61.27 % for 1alip, 76.06 % for 1aTlip. It is obvious that the targeted liposomes entrapped iridium(III) compound greatly enhance anti-cancer efficacy. Additionally, 1alip, 1blip and 1clip or targeted 1aTlip, 1bTlip and 1cTlip can effectively restrain the cell colony and proliferation in the G0/G1 period. 1alip, 1blip, 1clip, 1aTlip, 1bTlip and 1cTlip can increase reactive oxygen species (ROS) concentration, arouse a decline in the mitochondrial membrane potential and promote Ca2+ release. RNA-sequence was applied to examine the signaling pathways. Taken together, the liposomes or targeted liposomes encapsulated compounds trigger cell death by way of apoptosis, autophagy, ferroptosis, disruption of mitochondrial function and PI3K/AKT/mTOR signaling pathways.

A comparison of USP 2 and µDISS Profiler™ apparatus for studying dissolution phenomena of ibuprofen and its salts

BACKGROUND

Pharmaceutical salts of poorly soluble drugs typically dissolve faster than their corresponding free acid or base, resulting in supersaturation under some circumstances. The key questions relevant to drug bioavailability "does the salt invoke the supersaturated state?" and, if so, "does precipitation occur?" remain. To answer these questions, different types of dissolution equipment are often used at different stages of the development process.

AIM

To compare the dissolution behaviour of ibuprofen and its sodium and lysine salts in the USP 2 apparatus and the µDISS Profiler™ apparatus. The dissolution, supersaturation of the salt forms and precipitation to the free acid of ibuprofen were characterized along with the dissolution of the free acid form.

METHODS

Media containing different concentrations of the salt-forming counterions - sodium and lysine - were used to investigate the influence of the type of dissolution apparatus used for the study on dissolution, supersaturation and precipitation behaviour.

KEY RESULTS

Supersaturation was observed for both the sodium and lysinate salts of ibuprofen in all USP 2 apparatus and µDISS Profiler™ experiments. However, precipitation tended to be far greater in the µDISS Profiler™ than in the USP 2 apparatus. The difference was most pronounced in pH 4.5 acetate buffer, in which precipitation was observed exclusively in experiments with the µDISS Profiler™.

CONCLUSION

Choice of dissolution apparatus can affect the dissolution/supersaturation/precipitation characteristics of pharmaceutical salts. This has to be carefully taken into account when investigating salts over different stages of pharmaceutical research and development.

Integrated workflow for the identification of new GABAA R positive allosteric modulators based on the in silico screening with further in vitro validation. Case study using Enamine's stock chemical space

Numerous studies reported an association between GABAA R subunit genes and epilepsy, eating disorders, autism spectrum disorders, neurodevelopmental disorders, and bipolar disorders. This study was aimed to find some potential positive allosteric modulators and was performed by combining the in silico approach with further in vitro evaluation of its real activity. We started from the GABAA R-diazepam complexes and assembled a lipid embedded protein ensemble to refine it via molecular dynamics (MD) simulation. Then we focused on the interaction of α1β2γ2 with some Z-drugs (non-benzodiazepine compounds) using an Induced Fit Docking (IFD) into the relaxed binding site to generate a pharmacophore model. The pharmacophore model was validated with a reference set and applied to decrease the pre-filtered Enamine database before the main docking procedure. Finally, we succeeded in identifying a set of compounds, which met all features of the docking model. The aqueous solubility and stability of these compounds in mouse plasma were assessed. Then they were tested for the biological activity using the rat Purkinje neurons and CHO cells with heterologously expressed human α1β2γ2 GABAA receptors. Whole-cell patch clamp recordings were used to reveal the GABA induced currents. Our study represents a convenient and tunable model for the discovery of novel positive allosteric modulators of GABAA receptors. A High-throughput virtual screening of the largest available database of chemical compounds resulted in the selection of 23 compounds. Further electrophysiological tests allowed us to determine a set of 3 the most outstanding active compounds. Considering the structural features of leader compounds, the study can develop into the MedChem project soon.

Resolution of trans-1,2-cyclohexanedicarboxylic acid containing two carboxylic groups by forming diastereomeric salts based on feeding molar ratio control

To investigate the thermodynamic and molecular self-assembly mechanism of trans-1,2-cyclohexane dicarboxylic acid containing two carboxylic acid groups in the chiral resolution process, (S)-phenylethylamine was used as the chiral resolving agent. Two stoichiometric salts were formed when the raw materials were fed at different molar ratios: cyclohexane dicarboxylate monophenylethylamine salt and cyclohexane dicarboxylate diphenylethylamine salt. When the molar ratio of the (S)-phenylethylamine to trans-1,2-cyclohexane dicarboxylic acid was less than 3:1, trans-(1S,2S)-cyclohexane dicarboxylic acid was obtained with 97 e.e% purity. But when the molar ratio exceeded 3:1, the product was the racemic trans-(1,2)-cyclohexane dicarboxylic acid. In addition, single crystal structures of more soluble mono-salt, less soluble mono-salt, and less soluble di-salt were obtained. The weak intermolecular interactions and the way of the molecules packing in the crystals were analyzed. The hydrogen bond was stronger in the less soluble salt than that in the more soluble salt. And a "lock-and-key" structure in the hydrophobic layers makes it more tightly packed through the van der Waals interaction, which is responsible for the stability of less soluble salts.

Hyphenation of lipophilic ruthenium(II)-diphosphine core with 5-fluorouracil: an effective metallodrug against glioblastoma brain cancer cells

Glioblastoma multiforme (GBM) is the most common highly aggressive malignant brain tumor, with a very limited chance for survival post-diagnosis and post-treatment. Despite significant advancement in GBM genomics implicated in molecularly targeted chemotherapies, the prognosis remains poor and requires new drug discovery approaches. We used fluoropyrimidine 5-fluorouracil (5-FU), an antimetabolite anticancer drug conjugated or 'caged' within a lipophilic Ru(II)-diphosphine (dppe) core formulated as [RuII(dppe)2(5-FU)]PF6 (Ru-DPPE-5FU), where dppe = 1,2-bis(diphenylphosphino)ethane, and evaluated its in vitro cytotoxicity in depth with aggressive GBM cells (LN229). The hydrophilic nature of 5-FU limits its passage through the blood-brain barrier (BBB), which prevents its effective accumulation and efficacy for GBM tumors. Herein, we attempted to modulate the lipophilicity of 5-FU by inserting it within a well-designed lipophilic {Ru(dppe)2}-core with anticipated higher efficiency towards GBM. The physicochemical properties of [RuII(dppe)2(5-FU)]PF6 (Ru-DPPE-5FU) were studied using various spectroscopic and analytical techniques. The molecular structure was determined using X-ray crystallography, showing a distorted {RuP4NO} octahedral geometry with bidentate (N, O) binding of 5-FU and its aromatization in the Ru(II)-bound form. The 31P-NMR spectra of Ru-DPPE-5FU showed four closely spaced distinct 31P-signals, indicating four unique chemical environments around P, and the strong coupling constants between them make it a second-order spectrum. The RuII/RuIII redox potential in Ru-DPPE-5FU shifted by ∼0.91 V towards the anodic region as compared to its precursor complex cis-[Ru(dppe)2Cl2] (Ru-DPPE-Cl). DFT-based theoretical calculations have been performed to correlate the experimental electronic absorption spectra and redox behaviours of the complexes. The electrostatic potential (ESP) plots indicate the delocalization of the charge density on the O-/F-atom from the 5-FU ligand towards Ru(II) upon its complexation. The antioxidant properties of all the compounds were quantified by a 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay. The hyphenation of the 5-fluorouracil (5-FU) ligand to the lipophilic {Ru(dppe)2}-core endowed lipophilicity to Ru-DPPE-5FU with higher in vitro cytotoxicity (IC50 = 2.37 μM) against the LN229 GBM cells as compared to the hydrophilic 5-FU, suggesting efficient cellular uptake. Further biological assays indicated that the complex is highly potent in inhibiting significant proliferation and spheroid formation and restricting the migratory potentials of the GBM cells. Increased caspase 3/7 activity and the presence of apoptotic bodies at the center of 3-D GBM spheroids as revealed by AO/EB dual staining indicated a deeper penetration of the lipophilic complex. The Ru-DPPE-5FU complex displayed lower cytotoxicity in HaCaT normal cells (IC50 = 7.27 μM) in comparison to LN229 cancer cells with a selectivity index (S.I.) of ≥3. Overall, the synergism and caging of 5-FU within the hydrophobic {Ru(dppe)2}-core improves the pharmacokinetic profile of Ru-DPPE-5FU as a potent anticancer agent for glioblastoma.

The Development of an Oral Solution Containing Nirmatrelvir and Ritonavir and Assessment of Its Pharmacokinetics and Stability

Paxlovid®, a co-packaged medication comprised of separate tablets containing two active ingredients, nirmatrelvir (NRV) and ritonavir (RTV), exhibits good effectiveness against coronavirus disease 2019 (COVID-19). However, the size of the NRV/RTV tablets makes them difficult for some patients to swallow, especially the elderly and those with dysphagia. Therefore, an oral liquid formulation that can overcome this shortcoming and improve patient compliance is required. In this study, we developed a liquid formulation containing NRV and RTV by adopting strategies that used co-solvents and surfactants to enhance the solubility and inhibit possible recrystallization. The in vitro release results showed that NRV and RTV could be maintained at high concentrations in solution for a certain period in the investigated media. In vivo studies in rats showed that the oral bioavailability of NRV/RTV solution was significantly enhanced. Compared to Paxlovid® tablets, the AUC(0-t) of NRV and RTV increased by 6.1 and 3.8 times, respectively, while the Cmax increased by 5.5 times for both. Furthermore, the promoting effect of the absorption of RTV on the bioavailability of NRV was confirmed. Experiments with a beagle showed a similar trend. Stability studies were also conducted at 4 °C, 25 °C, and 40 °C for 90 days, indicating that the oral liquid formulation was physically and chemically stable. This study can be used as a valuable resource for developing and applying oral liquid NRV/RTV formulations in a clinical context.

Design and Synthesis of a Water-Based Nanodelivery Pesticide System for Improved Efficacy and Safety

Developing an environmentally friendly and safe nanodelivery system is crucial to improve the efficacy of pesticides and minimize environmental and health risks. However, preparing a completely water-based nanopesticide without using harmful solvents is a technical challenge. In this study, a water-based nanodelivery pesticide system was constructed to improve the efficacy and safety of Emamectin Benzoate (EB). A specific surfactant, 29-(4-(5-hydroxynonan-5-yl)phenoxy)-3,6,9,12,15,18,21,24,27-nonaoxanonacosan-1-ol (SurEB) was designed and synthesized to form a water-based nanodelivery system (EBWNS) with EB. Molecular dynamics simulations revealed the self-assembly and interaction forces between SurEB and EB in water, providing insights into the formation mechanism of EBWNS nanoparticles. The nanodelivery system showed the prolonged effectivity of EB with reduced degradation and demonstrated a good control efficacy for multiple target pests, such as red spider mite, beet armyworm larvae (Lepidoptera: Noctuidae), and rice stem borers (Chilo suppressalis). Toxicology tests on various objects demonstrated that the EBWNS has low toxicity for seeds, HaCaT cells, zebrafish, earthworm, and E. coli. This study provides a distinctive perspective for developing environmentally friendly nanopesticide formulations, which clarified a water-based treatment method for specific lipid-soluble pesticides. The water-based nanodelivery pesticide system has the potential to improve the efficacy and safety of pesticides in the process of field applications.

Comparative Drug Solubility Studies Using Shake-Flask Versus a Laser-Based Robotic Method

Drug solubility is of central importance to the pharmaceutical sciences, but reported values often show discrepancies. Various factors have been discussed in the literature to account for such differences, but the influence of manual testing in comparison to a robotic system has not been studied adequately before. In this study, four expert researchers were asked to measure the solubility of four drugs with various solubility behaviors (i.e., paracetamol, mesalazine, lamotrigine, and ketoconazole) in the same laboratory with the same instruments, method, and material sources and repeated their measurements after a time interval. In addition, the same solubility data were determined using an automated laser-based setup. The results suggest that manual testing leads to a handling influence on measured solubility values, and the results were discussed in more detail as compared to the automated laser-based system. Within the framework of unavoidable uncertainties of solubility testing, it is a possibility to combine minimal experimental testing that is preferably automated with mathematical modeling. That is a practical suggestion to support future pharmaceutical development in a more efficient way.

Study on Sulfamethoxazole-Piperazine Salt: A Mechanistic Insight into Simultaneous Improvement of Physicochemical Properties

Multidrug salts represent more than one drug in a crystal lattice and thus could be used to deliver multiple drugs in a single dose. It showcases unique physicochemical properties in comparison to individual components, which could lead to improved efficacy and therapeutic synergism. This study presents the preparation and scale-up of sulfamethoxazole-piperazine salt, which has been thoroughly characterized by X-ray diffraction and thermal and spectroscopic analyses. A detailed mechanistic study investigates the impact of piperazine on the microenvironmental pH of the salt and its effect on the speciation profile, solubility, dissolution, and diffusion profile. Also, the improvement in the physicochemical properties of sulfamethoxazole due to the formation of salt was explored with lattice energy contributions. A greater ionization of sulfamethoxazole (due to pH changes contributed by piperazine) and lesser lattice energy of sulfamethoxazole-piperazine contributed to improved solubility, dissolution, and permeability. Moreover, the prepared salt addresses the stability issues of piperazine and exhibits good stability behavior under accelerated stability conditions. Due to the improvement of physicochemical properties, the sulfamethoxazole-piperazine salt demonstrates better pharmacokinetic parameters in comparison to sulfamethoxazole and provides a strong suggestion for the reduction of dose. The following study suggests that multidrug salts can concurrently enhance the physicochemical properties of drugs and present themselves as improved fixed-dose combinations.

Enhanced biopharmaceutical performance of brick dust molecule nilotinib via stabilized amorphous nanosuspension using a facile acid-base neutralization approach

"Brick dust" compounds have high lattice energy as manifested by the poor aqueous solubility and suboptimal bioavailability. Nilotinib being a weakly basic brick dust molecule exhibits erratic and limited absorption during gastrointestinal transit, attributed to pre-absorptive factors like pH-dependent solubility, poor dissolution kinetics, and post-absorptive factors including P-gp-mediated drug efflux. In our study, these problems are addressed holistically by the successful fabrication of amorphous nanosuspension by an acid-base neutralization approach. The nanosuspension was obtained via rapid precipitation of nilotinib in an amorphous form and the generated in situ sodium chloride salt assisted in stabilizing the drug-loaded nanosuspension in a cage of salt and micellar stabilizer. Soluplus® and hypromellose acetate succinate (HPMCAS) were employed as a novel combination of stabilizers. Systematic optimization was carried out by employing the I-optimal method using Design Expert® software with a concentration of HPMCAS and Soluplus® as independent variables and evaluating them for responses viz particle size, polydispersity index (PDI), and zeta potential. The resultant nanosuspension showed a mean particle size of 130.5 ± 1.22 nm with a PDI value of 0.27 ± 0.01, and a zeta potential of - 5.21 ± 0.91 mV. The nanosuspension was further characterized for morphology, dissolution, and in vivo pharmacokinetics study. X-ray powder diffraction study of the nano-formulation displayed a halo pattern revealing the amorphous form. Stability studies showed that the nanosuspension remained stable at 40 °C ± 2 °C and 75% RH ± 5% RH for a period of three months. In vitro drug release and solubility study showed threefold and 36-fold enhancement in dissolution and solubility of the nanosuspension. Furthermore, an in vivo pharmacokinetic study in Sprague-Dawley rats following oral administration displayed a 1.46-fold enhancement in the relative bioavailability of the nanosuspension in contrast to neat nilotinib.

Avoid missing pKas: High-throughput workflow using solution pH-metric in tandem with UV-metric measurements

We describe a new high-throughput automated pKa workflow using potentiometry starting with 10 mM DMSO stock (solution pH-metric). Two approaches using either neat DMSO stock solution or removal of DMSO were evaluated with different sample amounts and cosolvent schemes. These were validated against traditional potentiometric measurements for optimal conditions. Further, we detail how high throughput solution pH-metric experiments are performed in tandem with established UV-metric measurements to capitalize on the advantages of both approaches. This new workflow maintains the sample and time savings required for measuring a large number of samples in a drug discovery setting, while avoiding "missing pKas" due to lack of sufficient UV chromophores. The combination of the two assays is key to tackle the challenges of low solubility, overlapping pKas, and preliminary assignment of pKas for Structure-Activity Relationship (SAR) understanding.

In vivo evaluation of time-dependent antithrombotic effect of rivaroxaban-loaded poly(lactic-co-glycolic acid)/sodium lauryl sulfate or didodecyl dimethylammonium bromide nanoparticles in Wistar rats

Rivaroxaban (RVX), an oral direct factor Xa inhibitor, is being explored as an alternative to traditional anticoagulans. However, RVX still faces pharmacokinetic limitations and adverse effects, highlighting the need for more effective formulations. In this regard, pharmaceutical nanotechnology, particularly the use of polymeric nanoparticles (PNPs), offers a promising approach for optimizing RVX delivery. This study aimed to develop and physicochemically characterize RVX-loaded poly(lactic-co-glycolic acid) (PLGA)/sodium lauryl sulfate (SLS) or didodecyl dimethylammonium bromide (DMAB) nanoparticles, and also evaluate their pharmacological and toxicological profiles as a potential therapeutic strategy. The PNPs exhibited sizes below 300 nm and spherical morphology, with both negative and positive surface charges, according to surfactant used. They demonstrated high encapsulation efficiency and suitable yields, as well as rapid initial liberation followed by sustained release in different pH environments. Importantly, in vivo evaluations revealed a time-dependent antithrombotic effect surpassing the free form of RVX when administered orally in SLS or DMAB PNP. No hemolytic or cytotoxic effects were observed at various concentrations of the PNPs. Interestingly, the PNPs did not induce hemorrhagic events or cause liver enzyme alterations in vivo. These findings suggest that RVX-loaded SLS or DMAB PNPs are promising innovative therapeutic alternatives for the treatment of thromboembolic diseases.

Quality-by-Design-Based Development of Rivaroxaban-Loaded Liquisolid Compact Tablets with Improved Biopharmaceutical Attributes

Rivaroxaban (RXN) finds use in the management of pulmonary embolism and deep vein thrombosis. Its poor solubility (5-7 µg/mL) and P-gp-mediated efflux from intestinal lining limits the oral application of RXN. This work assessed the impact of liquisolid compact technique in augmenting the solubility and bioavailability of RXN. PEG 400, Avicel PH 200, and Aerosil 200 were used as non-volatile liquid, carrier, and coating material, respectively, to formulate RXN liquid-solid compacts (RXN LSCs). A 32-factor factorial design was used in the optimisation to assess the impacts of factors (load factor and carrier:coating ratio) on the responses (angle of repose and Q30 min). Pre-compression parameters of RXN LSCs suggested adequate flow and compressibility. Optimisation data suggested significant influence of factors on both the responses. Optimised RXN LSC-based tablets showed a significantly higher in vitro dissolution rate than RXN API and Xarelto® tablets due to improved solubility, reduced crystallinity, greater surface area, and enhanced wetting of RXN particles. XRD, DSC, and SEM data supported RXN's amorphization. The cytotoxicity (MTT assay) and permeation studies indicated the nontoxicity of prepared RXN LSC tablets and the role of PEG 400 in inhibiting P-gp. Pharmacokinetic study of RXN LSC-based tablets in Albino Wistar rats exhibited 2.51- and 1.66-times higher AUC in comparison to RXN API and Xarelto® tablets respectively, demonstrating that developed formulation had a greater oral bioavailability. The RXN LSC tablets showed longer bleeding times and higher rates of platelet aggregation than RXN API. Thus, RXN LSC tablets can be considered a facile, scalable technology.

A Novel Betulinic Acid Analogue: Synthesis, Solubility, Antitumor Activity and Pharmacokinetic Study in Rats

Betulinic acid (BA) and betulin (BE) are naturally pentacyclic triterpenes with documented biological activities, especially antitumor and anti-inflammatory activity. However, their bioavailability in vivo is not satisfactory in terms of medical applications. Thus, to improve the solubility and bioavailability so as to improve the efficacy, 28-O-succinyl betulin (SBE), a succinyl derivative of BE, was synthesized and its solubility, in vitro and in vivo anti-tumor activities, the apoptosis pathway as well as the pharmacokinetic properties were investigated. The results showed that SBE exhibited significantly higher solubility in most of the tested solvents, and showed a maximum solubility of 7.19 ± 0.66 g/L in n-butanol. In vitro and in vivo anti-tumor activity assays indicated both BA and SBE exhibited good anti-tumor activities, and SBE demonstrated better potential compared to BA. An increase in the ratio of Bad/Bcl-xL and activation of caspase 9 was found in SBE treated Hela cells, suggesting that the intrinsic mitochondrial pathway is involved in SBE induced apoptosis. Compared with BA, SBE showed much-improved absorption and bioavailability in pharmacokinetic studies.

Solubility of hesperidin drug in aqueous biodegradable acidic choline chloride-based deep eutectic solvents

Important efforts have been made over the past years to improve the drug acts, which leads to the discovery of novel drug preparations and delivery systems. The selection of suitable green solvents for novel drug discovery and drug delivery depends on a molecular-level understanding of the interaction between drug molecules and the solvents. Deep eutectic solvents (DESs) are already used in sustainable extraction methods of natural products for their very high solvent power, high chemical and thermal stability, non-toxicity, and non-flammable. The thermodynamic investigation provides deep and complete knowledge of interactions and the choice of appropriate and suitable production compounds in pharmaceutical fields. Particularly, the analysis of drugs+DESs in aqueous media is a central issue in many types of research. This research is aimed to determine hesperidin (HES) solubility in water and DES solvents [choline chloride/citric acid (ChCl/CA), choline chloride/oxalic acid (ChCl/OA), choline chloride/malonic acid (ChCl/MA), and choline chloride/lactic acid (ChCl/LA)] at temperature range (298.15-313.15 K). Furthermore, the measured solubility data of HES in studied aqueous DESs solutions was fitted by models of Van't Hoff-Jouyban-Acree and Modified Apelblat-Jouyban-Acree. Finally, the Hansen solubility parameters as thermodynamic aspect for analyzing the dissolution processes for the four investigated aqueous DESs solutions were estimated.

Wedelolactone induces natural killer cell activity and the improvement to bioavailability using polysaccharides from Ligustri Lucidi Fructus

Wedelolactone (WDL) is the major bioactive component in Ecliptae Herba. This present study investigated the effects of WDL on natural killer cell functions and possible underlying mechanisms. It was proved that wedelolactone enhanced the killing ability of NK92-MI by upregulating the expression of perforin and granzyme B through the JAK/STAT signaling pathway. Additionally, wedelolactone could induce the migration of NK-92MI cells by promoting CCR7 and CXCR4 expressions. However, the application of WDL is limited due to poor solubility and bioavailability. Accordingly, this study investigated the impact of polysaccharides from Ligustri Lucidi Fructus (LLFPs) on WDL. The biopharmaceutical properties and pharmacokinetic characteristics were determined to compare WDL individually and in combination with LLFPs. The results showed that LLFPs could benefit the biopharmaceutical properties of WDL. Specifically, stability, solubility, and permeability were increased by 1.19-1.82-fold, 3.22-fold, and 1.08-fold higher than those of WDL alone, respectively. Furthermore, the pharmacokinetic study revealed that LLFPs could remarkably improve AUC_(0-t) (150.34 vs. 50.47 ng/mL ∗ h), t_1/2 (40.78 vs. 2.81 h), and MRT_(0-∞) (46.64 vs. 5.05 h) for WDL. In conclusion, WDL would be considered a potential immunopotentiator, and LLFPs could overcome the instability and insolubility, ultimately improving the bioavailability of this plant-derived phenolic coumestan.

Significant increase of anticancer efficacy in vitro and in vivo of liposome entrapped ruthenium(II) polypyridyl complexes

Two polypyridyl ruthenium(II) complexes [Ru(DIP)₂(BIP)](PF₆)₂ (DIP = 4,7-diphenyl-1,10-phenanthrolie, BIP = 2-(1,1'-biphenyl-4-yl)-1H-imidazo[4,5-f][1,10]phenanthroline, Ru1) and [Ru(DIP)₂(CBIP)](PF₆)₂ (CBIP = 2-(4'-chloro-1,1'-biphenyl-4-yl)-1H-imidazo[4,5-f][1,10]phenanthroline, Ru2) were synthesized. The cytotoxic activities in vitro of Ru1, Ru2 toward B16, A549, HepG2, SGC-7901, HeLa, BEL-7402, non-cancer LO2 were investigated using MTT method (3-(4,5-dimethylthiazole)-2,5-diphenltetraazolium bromide). Unexpectedly, Ru1, Ru2 can't prevent these cancer cells proliferation. To improve the anti-cancer effect, we used liposomes to entrap the complexes Ru1, Ru2 to form Ru1lipo, Ru2lipo. As expectation, Ru1lipo and Ru2lipo exhibit high anti-cancer efficacy, especially, Ru1lipo (IC₅₀ 3.4 ± 0.1 μM), Ru2lipo (IC₅₀ 3.5 ± 0.1 μM) display strong ability to block the cell proliferation in SGC-7901. The cell colony, wound healing, and cell cycle distribution show that the complexes can validly inhibit the cell growth at G2/M phase. Apoptotic studied with Annex V/PI doubling method showed that Ru1lipo and Ru2lipo can effectively induce apoptosis. Reactive oxygen species (ROS), malondialdehyde, glutathione and GPX4 demonstrate that Ru1lipo and Ru2lipo improve ROS and malondialdehyde levels, inhibit generation of glutathione, and finally result in a ferroptosis. Ru1lipo and Ru2lipo interact on the lysosomes and mitochondria and damage mitochondrial dysfunction. Additionally, Ru1lipo and Ru2lipo increase intracellular Ca²⁺ concentration and induce autophagy. The RNA-sequence and molecular docking were performed, the expression of Bcl-2 family was investigated by Western blot analysis. Antitumor in vivo experiments confirm that 1.23 mg/kg, 2.46 mg/kg of Ru1lipo possesses a high inhibitory rate of 53.53% and 72.90% to prevent tumor growth, hematoxylin-eosin (H&E) results show that Ru1lipo doesn't cause chronic organ damage and strongly promotes the necrosis of solid tumor. Taken together, we conclude that Ru1lipo and Ru2lipo cause cell death through the following pathways: autophagy, ferroptosis, ROS-regulated mitochondrial dysfunction, and blocking the PI3K/AKT/mTOR.

Development of Miconazole-Loaded Microemulsions for Enhanced Topical Delivery and Non-Destructive Analysis by Near-Infrared Spectroscopy

The antifungal drug miconazole nitrate has a low solubility in water, leading to reduced therapeutic efficacy. To address this limitation, miconazole-loaded microemulsions were developed and assessed for topical skin delivery, prepared through spontaneous emulsification with oleic acid and water. The surfactant phase included a mixture of polyoxyethylene sorbitan monooleate (PSM) and various cosurfactants (ethanol, 2-(2-ethoxyethoxy) ethanol, or 2-propanol). The optimal miconazole-loaded microemulsion containing PSM and ethanol at a ratio of 1:1 showed a mean cumulative drug permeation of 87.6 ± 5.8 μg/cm² across pig skin. The formulation exhibited higher cumulative permeation, permeation flux, and drug deposition than conventional cream and significantly increased the in vitro inhibition of Candida albicans compared with cream (p < 0.05). Over the course of a 3-month study conducted at a temperature of 30 ± 2 °C, the microemulsion exhibited favorable physicochemical stability. This outcome signifies its potential suitability as a carrier for effectively administering miconazole through topical administration. Additionally, a non-destructive technique employing near-infrared spectroscopy coupled with a partial least-squares regression (PLSR) model was developed to quantitatively analyze microemulsions containing miconazole nitrate. This approach eliminates the need for sample preparation. The optimal PLSR model was derived by utilizing orthogonal signal correction pretreated data with one latent factor. This model exhibited a remarkable R² value of 0.9919 and a root mean square error of calibration of 0.0488. Consequently, this methodology holds potential for effectively monitoring the quantity of miconazole nitrate in various formulations, including both conventional and innovative ones.

Versatile Solid Modifications of Multicomponent Pharmaceutical Salts: Novel Metformin-Rhein Salts Based on Advantage Complementary Strategy Design

This study aimed to develop an effective treatment for diabetes and diabetic complications, based on the advantage complementary strategy of drug-drug salt, by designing and synthesizing the multicomponent molecular salts containing metformin (MET) and rhein (RHE). Finally, the salts of MET-RHE (1:1), MET-RHE-H₂O (1:1:1), MET-RHE-ethanol-H₂O (1:1:1:1), and MET-RHE-acetonitrile (2:2:1) were obtained, indicating the polymorphism of salts formed by MET and RHE. The structures were analyzed by the combination of characterization experiments and theoretical calculation, and the formation mechanism of polymorphism was discussed. The obtained results of in vitro evaluation showed that MET-RHE had a similar hygroscopicity with metformin hydrochloride (MET·HCl), and the solubility of the component of RHE increased by approximately 93 times, which laid a foundation for improving the bioavailability of MET and RHE in vivo. The evaluation of hypoglycemic activity in mice (C57BL/6N) indicated that MET-RHE exhibited better hypoglycemic activity than the parent drugs and the physical mixtures of MET and RHE. The above findings demonstrate that this study achieved the complementary advantages of MET and RHE through the multicomponent pharmaceutical salification technique, and provides new possibilities for the treatment of diabetic complications.

Developing a Formulation Strategy Coupled with PBPK Modeling and Simulation for the Weakly Basic Drug Albendazole

Albendazole (ABZ) is a weakly basic drug that undergoes extensive presystemic metabolism after oral administration and converts to its active form albendazole sulfoxide (ABZ_SO). The absorption of albendazole is limited by poor aqueous solubility, and dissolution is the rate-limiting step in the overall exposure of ABZ_SO. In this study, PBPK modeling was used to identify formulation-specific parameters that impact the oral bioavailability of ABZ_SO. In vitro experiments were carried out to determine pH solubility, precipitation kinetics, particle size distribution, and biorelevant solubility. A transfer experiment was conducted to determine the precipitation kinetics. A PBPK model for ABZ and ABZ_SO was developed using the Simcyp™ Simulator based on parameter estimates from in vitro experiments. Sensitivity analyses were performed to assess the impact of physiological parameters and formulation-related parameters on the systemic exposure of ABZ_SO. Model simulations predicted that increased gastric pH significantly reduced ABZ absorption and, subsequently, ABZ_SO systemic exposure. Reducing the particle size below 50 µm did not improve the bioavailability of ABZ. Modeling results illustrated that systemic exposure of ABZ_SO was enhanced by increasing solubility or supersaturation and decreasing the drug precipitation of ABZ at the intestinal pH level. These results were used to identify potential formulation strategies to enhance the oral bioavailability of ABZ_SO.

Preparation and Characterization of Poly(vinyl Acetate-co-2-hydroxyethyl Methacrylate) and In Vitro Application as Contact Lens for Acyclovir Delivery

A series of poly(vinyl acetate-co-2-hydroxyethylmethacrylate)/acyclovir drug carrier systems (HEMAVAC) containing different acyclovir contents was prepared through bulk free radical polymerization of 2-hydroxyethyl methacrylate with vinyl acetate (VAc) in presence of acyclovir (ACVR) as the drug using a LED lamp in presence of camphorquinone as the photoinitiator. The structure of the drug carrier system was confirmed by FTIR and 1HNMR analysis, and the uniform dispersion of the drug particles in the carrier was proved by DSC and XRD analysis. The study of the physico-chemical properties of the prepared materials, such as the transparency, swelling capacity, wettability and optical refraction, was carried out by UV–visible analysis, a swelling test and measurement of the contact angle and the refractive index, respectively. The elastic modulus and the yield strength of the wet prepared materials were examined by dynamic mechanical analysis. The cytotoxicity of the prepared materials and cell adhesion on these systems were studied by LDH assay and the MTT test, respectively. The results obtained were comparable to those of standard lenses with a transparency of 76.90–89.51%, a swelling capacity of 42.23–81.80% by weight, a wettability of 75.95–89.04 o, a refractive index of 1.4301–1.4526 and a modulus of elasticity of 0.67–1.50 MPa, depending on the ACVR content. It was also shown that these materials exhibit no significant cytotoxicity; on the other hand, they show significant cell adhesion. The in vitro dynamic release of ACVR in water revealed that the HEMAVAC drug carrier can consistently deliver uniformly adequate amounts of ACVR (5.04–36 wt%) over a long period (7 days) in two steps. It was also found that the solubility of ACVR obtained from the release process was improved by 1.4 times that obtained by direct solubility of the drug in powder form at the same temperature.

Multi-Compartmental Dissolution Method, an Efficient Tool for the Development of Enhanced Bioavailability Formulations Containing Poorly Soluble Acidic Drugs

The purpose of this study was to investigate the applicability of the Gastrointestinal Simulator (GIS), a multi-compartmental dissolution model, to predict the in vivo performance of Biopharmaceutics Classification System (BCS) Class IIa compounds. As the bioavailability enhancement of poorly soluble drugs requires a thorough understanding of the desired formulation, the appropriate in vitro modelling of the absorption mechanism is essential. Four immediate release ibuprofen 200 mg formulations were tested in the GIS using fasted biorelevant media. In addition to the free acid form, ibuprofen was present as sodium and lysine salts in tablets and as a solution in soft-gelatin capsules. In the case of rapid-dissolving formulations, the dissolution results indicated supersaturation in the gastric compartment, which affected the resulting concentrations in the duodenum and the jejunum as well. In addition, a Level A in vitro-in vivo correlation (IVIVC) model was established using published in vivo data, and then the plasma concentration profiles of each formulation were simulated. The predicted pharmacokinetic parameters were consistent with the statistical output of the published clinical study. In conclusion, the GIS method was found to be superior compared to the traditional USP method. In the future, the method can be useful for formulation technologists to find the optimal technique to enhance the bioavailability of poorly soluble acidic drugs.

Nuclear Magnetic Resonance Method for Measuring Water Solubility of Organic Compounds

Water solubility measurements are required in drug discovery, in toxicological or environmental studies, and in developing industrial processes which employ extractions or crystallizations. The gold-standard shake-flask method is tedious and takes at least 24 h. We developed a nuclear magnetic resonance (NMR) method for automation, which has the same accuracy and solubility range as the shake-flask method, but a measurement can be made faster, since the analysis does not require separation of the phases. Samples of saturated solutions are analyzed in the presence of excess solute, since the NMR spectra do not show signals for the dispersed solids, and they tend to show separate signals for the dissolved and dispersed liquids. Spectra are acquired with water suppression, using a pulse sequence appropriate for quantitation. A sample of water is used as the external reference, and the concentration of the solute is determined using the PULCON relationship. An evaluation of the method in terms of selectivity, accuracy, precision, and limit of quantitation is presented in detail.

The Effect of the Particle Size Reduction on the Biorelevant Solubility and Dissolution of Poorly Soluble Drugs with Different Acid-Base Character

Particle size reduction is a commonly used process to improve the solubility and the dissolution of drug formulations. The solubility of a drug in the gastrointestinal tract is a crucial parameter, because it can greatly influence the bioavailability. This work provides a comprehensive investigation of the effect of the particle size, pH, biorelevant media and polymers (PVA and PVPK-25) on the solubility and dissolution of drug formulations using three model compounds with different acid-base characteristics (papaverine hydrochloride, furosemide and niflumic acid). It was demonstrated that micronization does not change the equilibrium solubility of a drug, but it results in a faster dissolution. In contrast, nanonization can improve the equilibrium solubility of a drug, but the selection of the appropriate excipient used for nanonization is essential, because out of the two used polymers, only the PVPK-25 had an increasing effect on the solubility. This phenomenon can be explained by the molecular structure of the excipients. Based on laser diffraction measurements, PVPK-25 could also inhibit the aggregation of the particles more effectively than PVA, but none of the polymers could hold the nanonized samples in the submicron range until the end of the measurements.

The Solubility Studies and the Complexation Mechanism Investigations of Biologically Active Spiro[cyclopropane-1,3'-oxindoles] with β-Cyclodextrins

In this work, we first improved the aqueous solubility of biologically active spiro[cyclopropane-1,3′-oxindoles] (SCOs) via their complexation with different β-cyclodextrins (β-CDs) and proposed a possible mechanism of the complex formation. β-CDs significantly increased the water solubility of SCOs (up to fourfold). Moreover, the nature of the substituents in the β-CDs influenced the solubility of the guest molecule (MβCD > SBEβCD > HPβCD). Complexation preferably occurred via the inclusion of aromatic moieties of SCOs into the hydrophobic cavity of β-CDs by the numerous van der Waals contacts and formed stable supramolecular systems. The phase solubility technique and optical microscopy were used to determine the dissociation constants of the complexes (Kc~102 M−1) and reveal a significant decrease in the size of the formed crystals. FTIR-ATR microscopy, PXRD, and 1H-1H ROESY NMR measurements, as well as molecular modeling studies, were carried out to elucidate the host−guest interaction mechanism of the complexation. Additionally, in vitro experiments were carried out and revealed enhancements in the antibacterial activity of SCOs due to their complexation with β-CDs.

Fabrication and characterization of orodispersible films loaded with solid dispersion to enhance Rosuvastatin calcium bioavailability

The present study was aimed to formulate and evaluate fast dissolving oral film of Rosuvastatin calcium to improve its bioavailability in comparison to typical solid oral dosage forms. The drug was formulated as solid dispersion with hydrophilic polymers and assessed for different constraints such as drug content, saturated solubility, and drug-polymer interaction. Best formula was selected and prepared in the form of orodispersible film. The films were developed by solvent casting method and examined for weight variations, drug content, folding endurance, pH, swelling profile, disintegration time, and in vitro dissolution. Further pharmacokinetic study was also performed on rabbit and compared with that of the marketed oral formulation. The drug and the polymers were found to be compatible with each other by FTIR study. Maximum solubility was found at drug polymer ratio of 1:4 and that was 54.53 ± 2.05 µg/mL. The disintegration time of the developed film was observed to be 10 ± 2.01 s, while release of the Rosuvastatin from the film was found to be 99.06 ± 0.40 in 10 min. Stability study shown that developed film was stable for three months. Further pharmacokinetic study revealed that developed orodispersible film had enhance oral bioavailability as compared to marketed product (Crestor® tablets). Conclusively, the study backs the development of a viable ODF of Rosuvastatin with better bioavailability.

Orally delivered rutin in lipid-based nano-formulation exerts strong antithrombotic effects by protein disulfide isomerase inhibition

Thrombosis occurs in both macrovasculature and microvasculature, causing various cardio-cerebral vascular diseases. The lack of effective and safe antithrombotic drugs leads to a public health crisis. Mounting evidence suggests that protein disulfide isomerase (PDI) plays a critical role in the initial stage of thrombus formation, motivating the research of the feasibility of PDI inhibitors as novel anti-thrombotics. Rutin, one of the most potent PDI inhibitors, was reported to suppress platelet aggregation and thrombosis in animal models, but further studies and clinical translation were restricted due to its low aqueous solubility and oral bioavailability. In this work, we fabricated rutin-loaded lipid-based nano-formulation (NanoR) and characterized their physical-chemical properties, release profiles, pharmacokinetic process, and pharmacodynamic function against thrombosis in macrovessels and microvessels. NanoR provided increased solubility and dissolution of rutin to achieve earlier T_max and higher C_max than the sodium salt of rutin (NaR) after oral gavage. Ex vivo studies demonstrated that NanoR significantly inhibited thrombin generation and clot formation in the plasma of mice. Importantly, such effect was reversed by exogenous recombinant PDI, demonstrating the specificity of the NanoR. In direct current-induced arterial thrombosis model and ferric chloride-induced microvascular thrombosis model, NanoR exhibited greatly enhanced antithrombotic activity compared with NaR. NanoR also showed good safety performance according to tail bleeding assay, global coagulation tests, and histological analysis. Overall, our current results indicated that NanoR offers a promising antithrombotic treatment with potential for clinical translation.

Novel Ru(II)-bipyridine/phenanthroline-lapachol complexes as potential anti-cancer agents

For the first time, we herein report on the syntheses of two new Ru(II)/bipyridine/phenanthroline complexes containing lapachol as ligand: complex (1), [Ru (bipy)₂(Lap)]PF₆ and complex (2), [Ru(Lap)(phen)₂]PF₆, where bipy = 2,2'-bipyridine and ph en = 1,10-phenanthroline; Lap = lapachol (2-hydroxy-3-(3-methylbut-2-en-1- yl)naphthalene-1,4-dione). The complexes were synthesized and characterized by elemental analyses, molar conductivity, mass spectrometry, ultraviolet-visible and infrared spectroscopies, nuclear magnetic resonance (¹H, ¹³C), and single crystal X-ray diffraction, for complex (2). In addition, in vitro cytotoxicity was tested against six cancer cells: A549 (lung carcinoma); DU-145 (human prostate carcinoma); HepG2 (human hepatocellular carcinoma), PC-3 (human prostate adenocarcinoma); MDA-MB-231 (human breast adenocarcinoma); Caco-2 (human colorectal adenocarcinoma), and against two non-cancer cells, FGH (human gingival normal fibroblasts) and PNT-2 (prostate epithelial cells). Complex (1) was slightly more toxic and selective than complex (2) for all cell lines, except against the A549 cells, where (2) was more potent than complex (1). The complexes induced an increase in the reactive oxygen species, and the co-treatment with N-acetyl-L-cysteine remarkably suppressed the ROS generation and prevented the reduction of cell viability, suggesting that the cytotoxicity of the complexes is related to the ROS-mediated pathway. Further studies indicated that the complexes may bind to DNA via minor groove interaction. Our studies also revealed that free Lap induces gene mutations in Salmonella Typhimurium, nevertheless, the complexes demonstrated the absence of genotoxicity by the Ames test. The present study provides a relevant contribution to understanding the anti-cancer potential and genetic toxicological events of new ruthenium complexes containing the lapachol molecule as a ligand.

Understanding the pH Dependence of Supersaturation State-A Case Study of Telmisartan

Creating supersaturating drug delivery systems to overcome the poor aqueous solubility of active ingredients became a frequent choice for formulation scientists. Supersaturation as a solution phenomenon is, however, still challenging to understand, and therefore many recent publications focus on this topic. This work aimed to investigate and better understand the pH dependence of supersaturation of telmisartan (TEL) at a molecular level and find a connection between the physicochemical properties of the active pharmaceutical ingredient (API) and the ability to form supersaturated solutions of the API. Therefore, the main focus of the work was the pH-dependent thermodynamic and kinetic solubility of the model API, TEL. Based on kinetic solubility results, TEL was observed to form a supersaturated solution only in the pH range 3–8. The experimental thermodynamic solubility-pH profile shows a slight deviation from the theoretical Henderson–Hasselbalch curve, which indicates the presence of zwitterionic aggregates in the solution. Based on pK_a values and the refined solubility constants and distribution of macrospecies, the pH range where high supersaturation-capacity is observed is the same where the zwitterionic form of TEL is present. The existence of zwitterionic aggregation was confirmed experimentally in the pH range of 3 to 8 by mass spectrometry.

Cyclodextrin Derivative Enhances the Ophthalmic Delivery of Poorly Soluble Azithromycin

Azithromycin (AZM), a macrolide antibiotic used for the treatment of chlamydial conjunctivitis, is less effective for the treatment of this disease due to its poor bioavailability (38%). Various alternatives have been developed for improving the physicochemical properties (i.e., solubility) of the AZM without much success. To overcome the problems associated with AZM, an inclusion complex employing a modified cyclodextrin, i.e., sulfobutylether-β-cyclodextrin (SBE-β-CD), was prepared and characterized by phase solubility studies and PXRD techniques. The results portrayed the formation of an inclusion complex of AZM with SBE-β-CD in 1:2 molar stoichiometric ratios. This inclusion complex was later incorporated into a polymer matrix to prepare an in situ gel. Various combinations of Carbopol 934P and hydroxypropyl methylcellulose (HPMC K4M) polymers were used and evaluated by rheological and in vitro drug release studies. The optimized formulation (F4) containing Carbopol 934P (0.2% w/v) and HPMC K4M (0.2% w/v) was evaluated for clarity, pH, gelling capacity, drug content, rheological properties, in vitro drug release pattern, ocular irritation test, and antimicrobial efficacy. Finally, owing to the improved antimicrobial efficacy and increased residence time, the AZM:SBE-β-CD in situ gel was found to be a promising formulation for the efficient treatment of bacterial ocular disease.

Enhanced stability and oral bioavailability of erlotinib by solid self nano emulsifying drug delivery systems

The present investigation demonstrates the preparation of solid self nanoemulsfying drug delivery system (sSNEDDS) to enhance stability and bioavailability of Erlotinib (ERL) via the oral route. Capmul®MCM EP (CPM EP, oil), Cremophor® RH 40 (CMR RH 40, surfactant), and LBF CS (LBF CS, cosurfactant) were chosen as chief components for preparing Liquids SNEDDS (L-ERL-SNEDDS) based on solubility and emulsion forming ability. Pseudo ternary phase diagram and constrained mixture designs were applied to identify the self-emulsifying area and it was found that CPM EP, CMR RH 40, and LBF CS in the ratio of 59:11:30 showed optimized particle size (110.08 nm), with narrow PDI (0.114) and high ERL loading capacity (14.31 mg/g). Adsorption method was implemented for solidification of L-ERL-SNEDDS. Among various solid carriers were studied, Aerosil® 200 (A200) was finalized based on free flowing property and reconstitution ability. DSC and XRD studies revealed that crystallinity of drug was reduced in developed system. The developed formulation (named as, A200-ERL-sSNEDDS) showed increased cytotoxicity and apoptosis in PANC-1 and MIA PaCa-2 cells. Pharmacokinetic studies revealed ∼2.2 times increase in AUC0-∞values in case of A200-ERL-sSNEDDS as compared to free ERL. Thus current strategy can be extrapolated for delivering of poorly soluble drugs via oral route.

Techno-Economic Analysis as a Driver for Optimisation of Cellobiose Lipid Fermentation and Purification

Cellobiose lipids (CL) are glycolipids synthesized by Ustilaginaceae species with potential application as detergents or in cosmetics. This study identified process optimisation potential for CL fermentation based on process modelling and techno-economic analysis. Using a stoichiometric equation based on laboratory data, we calculated the maximum possible CL yield YP/S of 0.45 gCL·gglucose−1 at the biomass yield of 0.10 gBiomass·gglucose−1 with an Ustilago maydis strain. Due to substrate inhibition that may occur at high glucose concentrations, a fed-batch process to increase biomass and CL concentrations was considered in our model. Simulation of different process scenarios showed that the choice of aeration units with high oxygen transfer rates and adaptation of power input to oxygen uptake can significantly decrease electricity consumption. We further assessed scenarios with different fermentation media and CL purification methods, suggesting additional process optimisation potential. Here the omission of vitamins from the fermentation medium proved to be a possible mean to enhance process economy, without compromising CL productivity.

Monolaurin-Loaded Gel-Like Microemulsion for Oropharyngeal Candidiasis Treatment: Structural Characterisation and In Vitro Antifungal Property

Recently, monolaurin (ML) has received great interest due to its possible use as an alternative antifungal. However, the limited water solubility of ML is still a major obstacle to its formulation and application. Gel-like microemulsions are one of the promising carriers for low-water-solubility substances due to both the advantages of gels and microemulsions and may be applied for ML. In this study, ML was incorporated into gel-like microemulsions and evaluated for its physicochemical and antifungal properties. The results indicated that the properties of gel-like microemulsion changed after the incorporation of ML, suggesting that ML can induce the transition of internal structure. When simulating the oral cavity environment, changes in the microstructure were observed and depended on the times of dilution. The lamellar structure was formed at 1.5-2 times dilution. However, this structure was disrupted after dilution five times or more. The structural change following dilution was associated with the release profiles. After contacting the formulations with the medium, ML was promptly released, with the majority of ML being released within 2 h. Regarding the antifungal assay, the ML-loaded gel-like microemulsions decreased the survival of Candida albicans within 3 h, although ML was immediately released, suggesting that the ML-loaded in oil droplets required time to permeate through the fungal cell wall. Additionally, the gel-like microemulsions possessed acceptable stability after the temperature cycling test. Therefore, gel-like microemulsions can be a possible carrier for ML loading, and ML-loaded gel-like microemulsions may be applied as an alternative antifungal preparation in the future. Graphical abstract.

Gastric ulcer healing by chebulinic acid solid dispersion-loaded gastroretentive raft systems: preclinical evidence

Background: Chebulinic acid (CA), a component in Terminalia chebula, exhibits antiulcer activity, but has poor aqueous solubility. Raft-forming systems incorporating solid dispersions (SDs) of CA, were developed to overcome its poor biopharmaceutical properties and to prolong the gastric residence time for maximum activity. Methods: SDs were formulated by a solvent evaporation method using Eudragit EPO. Raft formulations consisted of sodium alginate as a polymer. Results: Release of CA in the dissolution medium was 40%, whereas SDs showed 95.45% release. The CA raft system (20 mg/kg) showed curative efficacy in an alcohol-induced gastric ulcer model and increased protection when compared with omeprazole (10 mg/kg) and CA suspension (20 mg/kg). Conclusion: These studies demonstrated SD raft systems to be a promising approach for antiulcer therapy by CA.

Preparation and characterization of innovative electrospun nanofibers loaded with pharmaceutically applicable ionic liquids

Keeping up with cutting edge research in the field of drug delivery, the overall goal of this study was to develop innovative electrospun nanofibers loaded with ionic liquids (ILs) as active pharmaceutical ingredients (APIs). For the first time, a novel approach was examined by combining biocompatible polymer, poly (ethylene oxide) (PEO), and pharmaceutical ILs in an electrospinning process to develop nanofibers with high drug loading (up to 47%). Firstly, two well-known local anaesthetic drugs, lidocaine and procaine, were modified into ILs with the salicylate, forming lidocaine salicylate and procaine salicylate. Its dual-functional nature and increased water solubility for 4- to 10-fold depending on the drug used contribute to overcoming current hurdles encountered by APIs such as poor solubility, low bioavailability, and polymorphism of the solid-state. Nanofibers were formulated using solutions tested for density, viscosity, electrical conductivity, and small-angle X-ray scattering by varying PEO molecular weight and the PEO to IL mass ratio. Scanning electron microscopy showed the surface morphology of the obtained nanofibers, while Fourier transform infrared spectroscopy and differential scanning calorimetry confirmed IL in the nanofibers in an amorphous state. Thus, nanofibers with incorporated IL represent well-known drugs in the new form and a novel dermal application delivery system.

Integration of In Silico, In Vitro and In Situ Tools for the Preformulation and Characterization of a Novel Cardio-Neuroprotective Compound during the Early Stages of Drug Development

The main aim of this work is the biopharmaceutical characterization of a new hybrid benzodiazepine-dihydropyridine derivative, JM-20, derived with potent anti-ischemic and neuroprotective effects. In this study, the pKa and the pH-solubility profile were experimentally determined. Additionally, effective intestinal permeability was measured using three in vitro epithelial cell lines (MDCK, MDCK-MDR1 and Caco-2) and an in situ closed-loop intestinal perfusion technique. The results indicate that JM-20 is more soluble at acidic pH (9.18 ± 0.16); however, the Dose number (Do) was greater than 1, suggesting that it is a low-solubility compound. The permeability values obtained with in vitro cell lines as well as with the in situ perfusion method show that JM-20 is a highly permeable compound (Caco-2 value 3.8 × 10-5). The presence of an absorption carrier-mediated transport mechanism was also demonstrated, as well as the efflux effect of P-glycoprotein on the permeability values. Finally, JM-20 was provisionally classified as class 2 according to the biopharmaceutical classification system (BCS) due to its high intestinal permeability and low solubility. The potential good oral absorption of this compound could be limited by its solubility.