DSC, TGA-FTIR and FTIR Assisted by Chemometric Factor Analysis and PXRD in Assessing the Incompatibility of the Antiviral Drug Arbidol Hydrochloride with Pharmaceutical Excipients.

Arbidol hydrochloride is an antiviral product widely used in Russia and China for the treatment of, among other diseases, influenza. In recent years, it has turned out to be highly effective against COVID-19. However, there is little knowledge about its physicochemical properties and its behavior in the presence of various pharmaceutical excipients, which could be useful in the development of new preparations by increasing its solubility and bioavailability. For this reason, binary mixtures composed of arbidol hydrochloride and selected pharmaceutical excipients such as chitosan, polyvinylpyrrolione K-30 and magnesium stearate were prepared and subjected to differential scanning calorimetry (DSC), thermogravimetry combined with Fourier transform infrared spectrometry (TGA-FTIR) and Fourier transform infrared spectrometry (FTIR) analyses. In order to obtain clarity in the interpretation of the outcomes, chemometric calculations with factor analysis (FA) were used. Additionally, a powder X-ray diffraction (PXRD) and an intrinsic dissolution rate study were performed for arbidol hydrochloride itself and in the presence of excipients. As a result of the study, it was revealed that arbidol hydrochloride may undergo polymorphic transformations and be incompatible with chitosan and magnesium stearate. However, mixing arbidol hydrochloride with polyvinylpyrrolidone K-30 guarantees the obtaining of durable and safe pharmaceutical preparations.

Evaluation of Physicochemical Properties of Ipsapirone Derivatives Based on Chromatographic and Chemometric Approaches.

Drug discovery is a challenging process, with many compounds failing to progress due to unmet pharmacokinetic criteria. Lipophilicity is an important physicochemical parameter that affects various pharmacokinetic processes, including absorption, metabolism, and excretion. This study evaluated the lipophilic properties of a library of ipsapirone derivatives that were previously synthesized to affect dopamine and serotonin receptors. Lipophilicity indices were determined using computational and chromatographic approaches. In addition, the affinity to human serum albumin (HSA) and phospholipids was assessed using biomimetic chromatography protocols. Quantitative Structure-Retention Relationship (QSRR) methodologies were used to determine the impact of theoretical descriptors on experimentally determined properties. A multiple linear regression (MLR) model was calculated to identify the most important features, and genetic algorithms (GAs) were used to assist in the selection of features. The resultant models showed commendable predictive accuracy, minimal error, and good concordance correlation coefficient values of 0.876, 0.149, and 0.930 for the validation group, respectively.

Evaluation of the Effect of Antibacterial Peptides on Model Monolayers.

The aim of the study was to assess the effect of the synthesized antibacterial peptides: P2 (WKWK)2-KWKWK-NH2, P4 (C12)2-KKKK-NH2, P5 (KWK)2-KWWW-NH2, and P6 (KK)2-KWWW-NH2 on the physicochemical properties of a model biological membrane made of azolectin or lecithin. The Langmuir Wilhelmy method was used for the experiments. Based on the compressibility factor, it was determined that the monolayers formed of azolectin and peptides in the aqueous subphase are in the condensed liquid phase. At the boundary between the condensed and expanded liquid phases, there was a monolayer made of lecithin and P4, P5 or P6 in the aqueous subphase. In turn, the film consisting of lecithin alone (37.7 mN/m) and lecithin and P2 (42.6 mN/m) in the water subphase was in the expanded liquid phase. All peptides change, to varying degrees, the organization and packing of molecules in the monolayer, both those made of azolectin and of lecithin. The test results can be used for further research to design a system with the expected properties for specific organisms.

Modeling of Anticancer Sulfonamide Derivatives Lipophilicity by Chemometric and Quantitative Structure-Retention Relationships Approaches.

Sulfonamides are a classic group of chemotherapeutic drugs with a broad spectrum of pharmacological action, including anticancer activity. In this work, reversed-phase high-performance liquid chromatography and biomimetic chromatography were applied to characterize the lipophilicity of sulfonamide derivatives with proven anticancer activities against human colon cancer. Chromatographically determined lipophilicity parameters were compared with obtained logP, employing various computational approaches. Similarities and dissimilarities between experimental and computational logP were studied using principal component analysis, cluster analysis, and the sum of ranking differences. Furthermore, quantitative structure-retention relationship modeling was applied to understand the influences of sulfonamide's molecular properties on lipophilicity and affinity to phospholipids.

Antimicrobial and Antioxidative Activity of Newly Synthesized Peptides Absorbed into Bacterial Cellulose Carrier against Acne vulgaris.

The ongoing search for effective treatment of Acne vulgaris is concentrated, i.a., on natural peptides with antimicrobial properties. The aim of this work was the development of new amino acid derivatives with potential activity on dermal infections against selected microorganisms, including the facultative anaerobe C. acne. The peptides P1-P6 were synthesized via Fmoc solid phase peptide synthesis using Rink amide AM resin, analyzed by RP-HPLC-MS, FTIR, DPPH radical scavenging activity, and evaluated against C. acne and S. aureus, both deposited and non-deposited in BC. Peptides P1-P6 presented a lack of cytotoxicity, antimicrobial activity, or antioxidative properties correlated with selected structural properties. P2 and P4-P6 sorption in BC resulted in variable data, i.a., confirming the prospective topical application of these peptides in a BC carrier.

A Novel Approach to Optimize Hot Melt Impregnation in Terms of Amorphization Efficiency.

In this study, an innovative methodology to optimize amorphization during the hot melt impregnation (HMI) process was proposed. The novelty of this report revolves around the use of thermal analysis in combination with design of experiments (DoEs) to reduce residual crystallinity during the HMI process. As a model formulation, a mixture of ibuprofen (IBU) and Neusilin was used. The main aim of the study was to identify the critical process parameters of HMI and determine their optimal values to assure a robust impregnation process and possibly the highest possible amorphization rate of IBU. In order to realize this, a DoE approach was proposed based on a face-centered composite design involving three factors. The IBU/Neusilin ratio, the feeding rate, and the screw speed were considered as variables, while the residual crystallinity level of IBU, determined using differential scanning calorimetry (DSC), was measured as the response. Additionally, the stability of IBU under HMI was analyzed using high-performance liquid chromatography to estimate the extent of potential degradation. In order to verify the correctness of the DoE model, tested extrudates were manufactured by HMI and the obtained extrudates were thoroughly examined using scanning electron micrography, X-ray powder diffraction, and DSC.

Affinity of Antifungal Isoxazolo[3,4-b]pyridine-3(1H)-Ones to Phospholipids in Immobilized Artificial Membrane (IAM) Chromatography.

Currently, rapid evaluation of the physicochemical parameters of drug candidates, such as lipophilicity, is in high demand owing to it enabling the approximation of the processes of absorption, distribution, metabolism, and elimination. Although the lipophilicity of drug candidates is determined using the shake flash method (n-octanol/water system) or reversed phase liquid chromatography (RP-LC), more biosimilar alternatives to classical lipophilicity measurement are currently available. One of the alternatives is immobilized artificial membrane (IAM) chromatography. The present study is a continuation of our research focused on physiochemical characterization of biologically active derivatives of isoxazolo[3,4-b]pyridine-3(1H)-ones. The main goal of this study was to assess the affinity of isoxazolones to phospholipids using IAM chromatography and compare it with the lipophilicity parameters established by reversed phase chromatography. Quantitative structure-retention relationship (QSRR) modeling of IAM retention using differential evolution coupled with partial least squares (DE-PLS) regression was performed. The results indicate that in the studied group of structurally related isoxazolone derivatives, discrepancies occur between the retention under IAM and RP-LC conditions. Although some correlation between these two chromatographic methods can be found, lipophilicity does not fully explain the affinities of the investigated molecules to phospholipids. QSRR analysis also shows common factors that contribute to retention under IAM and RP-LC conditions. In this context, the significant influences of WHIM and GETAWAY descriptors in all the obtained models should be highlighted.

Lipophilicity Determination of Quaternary (Fluoro)Quinolones by Chromatographic and Theoretical Approaches.

Lipophilicity is a vital physicochemical parameter of a molecule, which affects several biological processes such as absorption, tissue distribution, and pharmacokinetic properties. In this study, evaluation of lipophilicities of a series of novel fluoroquinolone-Safirinium dye hybrids using chromatographic and computational methods is presented. Fluoroquinolone-Safirinium dye hybrids have been synthesized as new dual-acting hydrophilic antibacterial agents. Reversed phase thin-layer chromatography and micellar electrokinetic chromatography experiments were carried out. Furthermore, logP values of the target structures were predicted by means of different software platforms and algorithms. In order to assess similarities and dissimilarities of the obtained lipophilicity indexes, cluster analysis and sum of ranking differences were performed. The significant differences of calculated logP values (α = 0.05, p < 0.001) indicated that an experimental approach is necessary for lipophilicity prediction of this class of antibiotics. Chromatographic data indicated that the newly synthesized hybrid (fluoro)quinolone-based quaternary ammonium derivatives show less lipophilic character than the parent (fluoro)quinolones. Additionally, the chromatographically obtained lipophilicity indexes were evaluated for possible application in quantitative retention-activity relationships. The established lipophilicity models have the potential to predict antimicrobial activities of a series of quaternary (fluoro)quinolones against Bacillus subtilis, Escherichia coli, and Proteus vulgaris.

Antibacterial Activities of Lipopeptide (C10)2-KKKK-NH2 Applied Alone and in Combination with Lens Liquids to Fight Biofilms Formed on Polystyrene Surfaces and Contact Lenses.

The widespread use of biomaterials such as contact lenses is associated with the development of biofilm-related infections which are very difficult to manage with standard therapies. The formation of bacterial biofilms on the surface of biomaterials is associated with increased antibiotic resistance. Owing to their promising antimicrobial potential, lipopeptides are being intensively investigated as novel antimicrobials. However, due to the relatively high toxicity exhibited by numerous compounds, a lot of attention is being paid to designing new lipopeptides with optimal biological activities. The principal aim of this study was to evaluate the potential ophthalmic application of lipopeptide (C10)2-KKKK-NH2. This lipopeptide was synthesized according to Fmoc chemistry using the solid-phase method. The antibiofilm activities of the lipopeptide, antibiotics used in ocular infections, and commercially available lens liquids were determined using the broth dilution method on polystyrene 96-well plates and contact lenses. Resazurin was applied as the cell-viability reagent. The effectiveness of the commercially available lens liquids supplemented with the lipopeptide was evaluated using the same method and materials. (C10)2-KKKK-NH2 exhibited stronger anti-biofilm properties compared to those of the tested conventional antimicrobials and showed the ability to enhance the activity of lens liquids at relatively low concentrations (4⁻32 mg/L). Estimation of the eye irritation potential of the lipopeptide using Toxtree software 2.6.13 suggests that the compound could be safely applied on the human eye. The results of performed experiments encourage further studies on (C10)2-KKKK-NH2 and its potential application in the prophylaxis of contact lens-related eye infections.

Characterization of antimicrobial and hemolytic properties of short synthetic cationic lipopeptides based on QSAR/QSTR approach.

In this study, we investigated the influence of molecular descriptors of cationic lipopeptides on their antimicrobial activity and hemolytic properties. The quantitative structure-activity relationship and quantitative structure-property relationship models were constructed. The antimicrobial, hemolytic and retention data were used as dependent variable and structural parameters as the independent ones. The obtained results suggest that the chromatographic indexes can be employed for prediction of antibacterial activity and that lipopeptides present nonspecific interaction between erythrocytes and bacterial membranes.

Synergistic Effect of Polyvinyl Alcohol and Copovidone in Itraconazole Amorphous Solid Dispersions.

PURPOSE: The first objective is to evaluate the feasibility of melt-extruding polyvinyl alcohol-based amorphous solid dispersions for oral drug delivery. The second objective is to investigate the miscibility between polyvinyl alcohol 4-88 and copovidone, and to characterize the properties of ternary itraconazole amorphous solid dispersions comprising both polymers. METHODS: Samples were prepared using a co-rotating, twin-screw extruder. A solution precipitation study was conducted to compare the precipitation inhibition of polyvinyl alcohol against other commonly used polymers for amorphous solid dispersions. Miscibility between polyvinyl alcohol 4-88 and copovidone was determined using DSC and XRD analyses. All extrudates were characterized using DSC, XRD, and non-sink dissolution. RESULTS: Polyvinyl alcohol demonstrated the highest capacity for inhibiting the precipitation of itraconazole. Itraconazole was found to be more soluble in copovidone (>30%) than in polyvinyl alcohol 4-88 (<5%) in binary extrudates. Polyvinyl alcohol and copovidone are miscible when the proportion of polyvinyl alcohol 4-88 does not exceed 30% (w/w). Compared to binary extrudates, the ternary extrudate demonstrated a higher degree of supersaturation and more sustained supersaturation of itraconazole in purified water and phosphate buffer pH 6.8 solution. CONCLUSION: As a surface-active material, polyvinyl alcohol was effective in inhibiting precipitation of itraconazole in aqueous media. Solubility of itraconazole in polyvinyl alcohol in solid state was limited because of the high polarity of the polymer. Ternary systems comprising a mixture of polyvinyl alcohol and copovidone demonstrated better supersaturation in aqueous media than binary systems. Ternary systems benefited from both the high solubilizing capacity of copovidone and high precipitation inhibition capacity of polyvinyl alcohol.

In Vitro Evaluation of Cytotoxicity and Permeation Study on Lysine- and Arginine-Based Lipopeptides with Proven Antimicrobial Activity.

Owing to their excellent antimicrobial activities with a relatively low cost of production, lipopeptides are being intensively investigated as potential alternatives to popular antimicrobials. However, a critical obstacle for their application is a relatively high toxicity, hence a lot of attention has been paid to designing new molecules with optimal properties. In this study we synthesized the following lipopeptides: C16-KK-NH2, C16-KεK-NH2, C16-KKK-NH2, C16-KRK-NH2, C16-RR-NH2, C16-RRR-NH2, (C10)2-KKKK-NH2 and (C12)2-KKKK-NH2. Their antimicrobial activity against representative strains of Gram-positive bacteria, Gram-negative bacteria and fungi has been confirmed. The compounds have been evaluated with regard to the safety of their application in dermatology. The cytotoxicity was determined in HaCaT keratinocytes using MTT assay, whereas Strat M membranes placed in Franz diffusion cells were used to assess their ability to skin permeation. The compounds containing one hexadecanoic acid chain turned out to be very toxic towards human keratinocytes, while lipopeptides containing two fatty acid chains (decanoic and dodecanoic) demonstrated much lower cytotoxicity. For the most promising lipopeptide, (C10)2-KKKK-NH2, the measured IC50 on HaCaT keratinocytes was few times higher as compared to MICs obtained for the tested bacteria. Both groups of lipopeptides did not permeate the model membranes and therefore lack of permeation through human skin could be expected. The results of this work encourage further research on the potential application of lipopeptides with two fatty acids as novel antimicrobials.

Formulation and In Vitro Characterization of Bioactive Mesoporous Silica with Doxorubicin and Metronidazole Intended for Bone Treatment and Regeneration.

The purpose of this study was to evaluate the surface mineralization activity and in vitro drug behavior potential of two forms of mesoporous silica: powder and granulate. Ordered mesoporous SiO2 powder was synthesized by surfactant-assisted sol-gel process using tetraethoxysilane as a silica precursor and hexadecyltrimethylammonium bromide as the structure-directing agent. The granulate was prepared using silica powder and ethyl cellulose as a binding agent. Metronidazole (MT)-an anti-inflammatory substance and doxorubicin hydrochloride (ChD)-an anti-cancer drug were chosen as drug models for delivery studies. The results of structural characteristic studies, utilizing transmission electron microscope (TEM) and scanning electron microscope (SEM) images, powder X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and nitrogen adsorption-desorption (BET) measurements, show that obtained materials have two-dimensional hexagonal p6mm symmetry, high specific surface area, narrow pore size, and a satisfactory mineralization behavior in the simulated body solution (SBF, pH = 7.4). The release rate of drugs depends upon the structural features of the drug molecules and the form of the carrier material. Of both the drugs analyzed, faster release was observed for small MT molecules characterized by weaker interactions with the carrier. In addition, the slower drug release was observed with granulate form due to increased diffusion barrier for drugs. Obtained results prove that the MT/ChD-loaded silica formulations could be attractive materials for filling bone defects and for local delivery systems.

INFLUENCE OF MICROCRYSTALLINE CELLULOSE MODIFICATION ON THE PHYSICAL PARAMETERS' STABILITY OF DIRECTLY COMPRESSED PLACEBO TABLETS.

Directly compressed tablets manufactured with high concentrations of microcrystalline cellulose tend to soften when exposed to high humidity. Modification/co-processing of microcrystalline cellulose with hydrophobic agents using two methods was proposed to prevent hardness decrease of placebo tablets upon moisture absorption. Hardness of placebo tablets before and after exposure to humidity of 75% RH was compared. Hardness of all tested placebo tablets decreased after exposure to humidity of 75% RH, however the extent of decrease was different. Relative hardness decrease was the lowest for modification with use of hydrogenated castor oil. Co-processing of microcrystalline cellulose by 20% addition of hydrogenated castor oil allows to reduce a hardness decrease upon moisture uptake.

EVALUATION OF CASES WITH THE USAGE OF COMMERCIALLY AVAILABLE TABLETS IN THE PEDIATRIC FORMULA.

Lack of availability, of either the medicinal product intended to be used for children, or such in a dose which is fitting for the individual child's needs, results in physicians administering medicines meant for the adult. The target of the thesis was to evaluate the cases with the usage of commercially avaible conventional tablet-formulated medicinal products intended for the adult in the pediatric formula. The subjects of the evaluation were the form of the pediatric drug, prepared from commercially available tablets and capsules, as well as the legitimacy of their usage in the treatment of the pediatric population. One hundred and fifty-four prescriptions filled in community pharmacies of Warminsko-Mazurskie Voivodeship in 2011 were chosen. A total of 5805 divided powders in starch capsules were prepared. The prescribing practice included 6 groups of manufactured medicinal products in the form of conventional tablets, containing as follows: anti-hypertensive medicines (ACE inhibitors--enalapril, captopril, ramipril, loop diuretics--furosemide, potassium sparing diuretics--spironolactone, ß-adrenolytics--propranolol, α- and ß-adrenolytics--carvedilol), medicines for heart failure (foxglove glycosides--digoxin, methyldigoxin), anti-clotting medicines (acetylsalicylic acid), peristalsis stimulating agents (metoclopramide), antibacterial medicines (furagin), and dopaminergic (carbidopa-levodopa). The only compounded forms ordered by the physicians were divided powders for an internal use. Starch capsules for powder preparation provided the only 'package' for the dose of the compounded powder, which after pouring, solving or suspending in water was administered to children. Such a shift of the form, between an oral tablet and divided powder for an internal use, did not cause a change in the method of administration. The information on indications and the way of dosage for children, inserted in the Summary of Product Characteristics, enables the administration which follows the registered indications, despite the shortage of an appropriate dose in the pharmaceutical market. In contrast, an absence of the information regarding the indications and a dosage for children in the Summary of Product Characteristic, results in an off-label administration, in case of a child.

Biological and surface-active properties of double-chain cationic amino acid-based surfactants.

Cationic amino acid-based surfactants were synthesized via solid phase peptide synthesis and terminal acylation of their α and ε positions with saturated fatty acids. Five new lipopeptides, N-α-acyl-N-ε-acyl lysine analogues, were obtained. Minimum inhibitory concentration and minimum bactericidal (fungicidal) concentration were determined on reference strains of bacteria and fungi to evaluate the antimicrobial activity of the lipopeptides. Toxicity to eukaryotic cells was examined via determination of the haemolytic activities. The surface-active properties of these compounds were evaluated by measuring the surface tension and formation of micelles as a function of concentration in aqueous solution. The cationic surfactants demonstrated diverse antibacterial activities dependent on the length of the fatty acid chain. Gram-negative bacteria and fungi showed a higher resistance than Gram-positive bacterial strains. It was found that the haemolytic activities were also chain length-dependent values. The surface-active properties showed a linear correlation between the alkyl chain length and the critical micelle concentration.

Biopharmaceutical evaluation of new slow release tablets obtained by hot tableting of coated pellets with tramadol hydrochloride.

This study was aimed at a biopharmaceutical evaluation of a new oral dosage form of tramadol hydrochloride (TH)--slow release tablets obtained by hot tableting of coated pellets, 100 mg (TP), compared to the conventional slow release tablets, Tramal Retard, 100 mg (TR). Both TP and TR formulations showed a similar release profile of TH (f2 was 71) in in vitro release studies. The in vivo study was a two-treatment, two-period, two-sequence, single-oral dose 100 mg, crossover design using rabbit model with the phases separated by a washout period of 14 days. It was shown that the amount of TH absorbed into the systemic circulation is similar for TP and TR (the 90% confidence intervals for the AUC(0-1), AUC(0-infinity) and ratios were 85-122 and 92-107%, respectively). However, after administration of slow release tablets obtained by hot tableting of coated pellets, a prolonged absorption and elimination processes and a smoother and more extended plasma profile of TH were observed. It can be assumed that the use of a new oral dosage form of TH in patients affects the extension of analgesia after single administration of the drug, with its gradual absorption into the systemic circulation.

In vitro - in vivo evaluation of a new oral dosage form of tramadol hydrochloride--controlled-release capsules filled with coated pellets.

The aim of this study was an in vitro - in vivo evaluation of a new oral dosage form of tramadol hydrochloride (TH), controlled-release capsules filled with coated pellets, 100 mg (TC), compared to the sustained release tablets, Tramal Retard, 100 mg (TR). In vitro release study of both formulations showed a similar release profile of TH over 8 h (f2 was 52). In vivo study (single oral, 100 mg dose administration in 8 rabbits) showed that the amount of TH absorbed into the systemic circulation after TC and TR administration was also similar (90% CI for AUC(0-t) and AUC(0-infinity) were 90-124% and 97-109%, respectively). However, a comparison of AUC(0-t) of pharmacokinetics of TC and TR indicates significantly prolonged absorption and elimination processes of TH when the drug is given in controlled-release capsules filled with coated pellets. It was manifested by longer: mean absorption time (p = 0.0016), mean residence time (p = 0.0268), absorption half-life (p = 0.0016), elimination half-life (p = 0.0493) and lower: absorption rate constant (p = 0.0016), elimination rate constant (p = 0.0148) and total body clearance Cl/F (p = 0.0076). It may be concluded that the new TH formulation could be expected to have a more prolonged analgesic activity than commercial sustained release tablets.

Modification of gradient HPLC method for determination of small molecules' affinity to human serum albumin under column safety conditions: Robustness and chemometrics study.

In the early stages of drug discovery, beyond the biological activity screening, determining the physicochemical properties that affect the distribution of molecules in the human body is an essential step. Plasma protein binding (PPB) is one of the most important investigated endpoints. Nevertheless, the methodology for measuring %PPB is significantly less popular and standardized than other physicochemical properties, like lipophilicity. Here, we proposed how to modify protocols presented by Valko into column safety conditions and evaluated their robustness using fractional factorial design. For robustness testing, four factors were selected: column temperature, mobile phase flow rate, maximum isopropanol concentration in the mobile phase, and buffer pH. Elaborate methods have been applied for the analysis of HSA affinity for three groups of antibiotic-oriented substances that vary in chemical structure: fluoroquinolones, sulfonamides, and tetrazole derivatives. Furthermore, based on the reversed-phase chromatography the workflow of pilot studies was proposed to select molecules that have high affinity to HSA and can not be eluted from the HSA column using the concentration of organic modifier recommended by the column manufacturer.

Influence of surfactants on the release behaviour and structural properties of sol-gel derived silica xerogels embedded with metronidazole.

The aim of this study was to obtain stable and controlled release silica xerogels containing metronidazole (MT) prepared with surfactants with different charges: cetyltrimethylammonium bromide (CTAB), sodium dodecyl sulphate (SDS) and hydroxypropyl cellulose (HPC), which could be the promising carrier materials used as the implantable drug delivery systems. The xerogels were prepared by the sol-gel method. The influence of various formulation precursors on porosity parameters and drug release were investigated. Addition of surfactants showed a promising result in controlling the MT release. Dissolution study revealed increased release of MT from silica modified SDS and CTAB, whereas the release of MT from silica modified HPC considerably decreased, in comparison with unmodified silica. The addition of surfactants showed slight changes in porosity parameters. All xerogels are characterized by a highly developed surface area (701-642 m(2) g(-1)) and mesoporous structure. The correlation between pore size obtained matrices and release rate of drug was also observed. Based on the presented results of this study, it may be stated that applied xerogel matrices: pure silica and surfactants-modified silica could be promising candidates for the formulation in local delivery systems.