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In recent years, core-shell nanofibrous drug delivery systems have received increasing attention due to their ability to incorporate two or more active pharmaceutical ingredients (APIs) individually into the desired layer (either core or sheath) and thereby finely tune the release profiles of even incompatible drugs in one system. This study aims to perform formulation and solid-state characterisation of levofloxacin-loaded polylactic acid (PLA) - naproxen-sodium-loaded polyvinyl pyrrolidone (PVP) bicomponent core-shell fibrous sheets and examine the electro spinnability of the precursor combinations. The selected drugs have potential therapeutic relevance in similar systems intended for wound healing; however, in this study, they are used as model drugs to understand the physicochemical properties of a drug loaded system. In order to determine the best core- and shell-solution combination, a full factorial experimental design is used. A combination of various morphological (scanning electron microscopy and transmission electron microscopy) and microstructural characterisation techniques (X-ray photoelectron spectroscopy and Raman spectroscopy) was applied to non-invasively obtain information about the structure of the fibres and the embedded drugs. The results indicate that core-shell fibres of different compositions could be successfully prepared with various structural homogeneities. The best core-shell structure was obtained using a combination of 15% (w/w) shell concentration and 8% (w/w) PLA solution concentration. In addition to the conventional core-shell structural verification methods, the Raman spectroscopy method was implemented to reveal not only the core-shell structure of the PLA/PVP nanofibers but also the form of the embedded drugs. The Raman mapping of the fibres confirm the above results, and it is shown that an amorphous solid dispersion is formed as a result of the coaxial electrospinning process., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Over the past several decades, the formulation of novel nanofiber-based drug delivery systems focusing on specific delivery purposes has been investigated worldwide with a continuous level of interest. The unique structure and properties of nanoscale fibrous systems, such as their high specific-area-to-volume ratio and high porosity and the possibility of controlling their crystalline-amorphous phase transitions, make them a desirable formulation pathway to satisfy the needs of recent pharmaceutical development. Fibrous delivery systems can facilitate the accelerated dissolution and increased solubility of small molecules and can also be useful in controlling drug delivery over time (for local or systemic drug administration). In the latter case, the release periods can be tuned over a wide range (from hours to weeks), e.g., by adjusting the fiber diameter and selecting the appropriate polymers. The solubility of the polymer, the fiber diameter and the fiber structure are the primary parameters affecting drug release. In addition to immediate and sustained release, other release profiles, such as biphasic release, can also be achieved. Chemical conjugation and surface functionalization offer further possibilities for the control of drug release. In the case of small molecules, developments focus mostly on overcoming the unfavorable physicochemical nature of the active agents. By contrast, in the preparation of macromolecule-loaded nanofibers, maximizing the biological activity of the macromolecules presents the greatest challenge. The authors' intent is to provide a comprehensive overview of the key parameters of advanced drug delivery systems of this type., (Copyright © 2015 Elsevier B.V. All rights reserved.)

Preformulation study of rotary spun hydroxypropyl cellulose fibers was carried out using the combination of textural characterization of gels in the concentration range of 42-60% w/w and optical microscopic evaluation of formed fibers. High adhesiveness values resulted in bead formation at lower polymer concentration, meanwhile fiber formation was hindered when high adhesiveness values were associated with high polymer content. The optimum gel concentration for fiber formation was given to 50% w/w. Drug loaded microfibers were prepared using a model drug of biopharmaceutical drug classification system class II. Fibers were milled, sieved and mixed with tableting excipients in order to directly compress orodispersible tablets. Hardness, friability, in vitro disintegration time values complied with the pharmacopoeial requirements. In vitro dissolution profiles obtained from three distinct dissolution media (pH 1.0; 4.5; 6.8) were quite differentiated compared to the compressed physical mixture of the same composition. Difference and similarity factors confirmed that the drug dissolution from microfiber based formula was almost independent from the pH value of the media. X-ray diffraction patterns indicated that the drug embedded in microfibers was in amorphous state, and the decrease of o-Ps lifetime values suggested that fiber formation enabled the development of a more ordered fibrous system., (Copyright © 2014 Elsevier B.V. All rights reserved.)

The active pharmaceutical ingredient can be administered by several different routes. Although the oral route (per os) has been one of the most convenient and widely accepted delivery system for most drugs, it has number of disadvantages like the very low pH of the stomach, the high enzymatic activity, and extensive first-pass metabolism. Difficulty in swallowing (dysphagia) is common among all age groups, especially in "problematic" subpopulations like children and the elderly. Several novel intraoral dosage forms (IODs) have recently become available to modulate the physicochemical and pharmacokinetic characteristics of drugs, while improving patient compliance. The present article summarizes and categorizes their formulation possibilities.

Beside the many advantages of intraarticular formulations (e.g., the systemic side effects are kept away), there is a big drawback. During the injections, there is the risk for infection therefore the number of injections in a year should be reduced. Also a long-term drug exposure should be achieved with an injection, and if it is possible, a combination of active ingredients should be used. At present there are only formulations with hyaluronic acid or glucocorticoid on the market. One of these formulations, a liposomal preparation, is of sustained drug release. Many different active ingredients could have a long-term drug exposure with carrier systems like micro- and nanoparticles, liposomes, hydrogels and physically activated delivery systems (thermoresponsive or magnetically modulated). The present paper gives an overview about these carrier systems, the novel scientific results and the aim of the future researches, as well.

The aim of the present study was to investigate how the drug release and FT-IR characteristics of metolose patches were influenced by the changes of Metolose SM 4000 (methylcellulose) and Metolose 90SH 100.000SR (hypromellose) proportions. FT-IR spectroscopy measurements were performed in parallel with the metoprolol tartrate release study to track the effect of the composition on the drug release. The metoprolol tartrate release profile of the patches was evaluated by Weibull distribution. Linear relationship was found with good correlation between the logarithm of time interval necessary to release 63.2% of metoprolol tartrate (tau(d) values) and the peak area measured within the characteristic FT-IR wavenumbers of patches. The application of FT-IR measurements can be recommended as a rapid, non-destructive screening method during the in-process control of patches., (Copyright 2010 Elsevier B.V. All rights reserved.)

The correlation between the release characteristics of metoprolol tartrate and the free volumes of Metolose patches containing Metolose 90SH 100.000SR (hypromellose) and Metolose SM 4000 (methylcellulose) of various proportions was studied. Positron annihilation lifetime spectroscopy (PALS) measurements were performed in parallel with the metoprolol tartrate release study to track the free volume changes of patches. Second-order polynomial relationship was found, with good correlation, between the metoprolol tartrate released at the 6th hour, the o-positronium lifetime, indicating the free volume of the polymer, and the Metolose SM 4000 relative proportions. The main reason for this correlation is the change in the free volume size of the polymer patches embedding metoprolol tartrate as a function of the relative proportion of Metolose 90SH 100.000SR containing hydroxypropoxy substitution. Since there were no significant changes between the free volumes of Metolose polymers at any ratio of the constituents in the case of lack of metoprolol tartrate, the free volume changes refer to a possible intermolecular interaction between the polymer and the active agent.

The aim of this study was to investigate the influence of two types of chlorhexidine species, chlorhexidine base and its salts, on the physico-chemical features of liquid crystalline systems and on drug transport through lipophilic membranes. A non-ionic surfactant, Synperonic A7 (PEG7-C13-15) was selected for the preparation of the liquid crystalline systems. Mixtures of different ratios of Synperonic A7 and water were prepared. The liquid crystalline systems were characterized using polarizing microscopy and dynamic oscillatory test. Membrane transport was also examined. The addition of chlorhexidine species to the liquid crystalline system modified the structure of the liquid crystalline system. As a result of the changes of liquid crystalline structures, the drug release of various types of chlorhexidine could be also modified. The combination of the base and salt forms of the drug in one dosage form could eliminate the drug release changes from liquid crystalline systems of dynamically changeable structures.

The physical stability of 2 types of total nutrient admixtures was studied as a function of storage time and temperature. One of them contained only structured triglycerides and the other exclusively long-chain triglycerides as lipid components. To evaluate the possible changes in the kinetic stability of the emulsions and in the surface characteristics of the droplets during storage, particle size analysis, zeta potential, and dynamic surface tension measurements were performed. To follow any chemical decomposition processes that occurred during storage, the pH of the emulsions was also monitored. The mean droplet size of emulsions prepared with lipids containing exclusively long-chain triglycerides showed a remarkable increase after 4 days of storage, in contrast with that of the mixtures containing structured lipids. A combination of size distribution, zeta potential, and dynamic surface tension measurements proved to be useful for an adequate tracking of the kinetic stability of total nutrient admixtures. Structured triglycerides not only provide advantageous metabolic effects but improve the physical stability of total parenteral nutrition admixtures.