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Introduction: An adequate hydration level is essential to maintain epidermal barrier functions and normal physiological activities of skin tissues. Diverse moisturizing agents and pharmaceutical formulations for dermal deliveries have thus extensively been investigated. This review comprehensively discusses scientific outcomes of moisturizing agents and pharmaceutical vehicles for skin moisturization, thereby providing insight into designing innovative pharmaceutical formulations for effective skin moisturization., Areas Covered: We discussed the functions of various moisturizing agents ranging from conventional creams to novel moisturizers which has recently been explored. In addition, novel pharmaceutical formulations for efficient dermal delivery of the moisturizers, in particular, nanocarriers, were discussed along with their uses in commercial products., Expert Opinion: Although various moisturizing agents have demonstrated their promising effects, exploitation of pharmaceutical formulations for their dermal delivery have been limited to few commonly used moisturizing agents. Thus, combinatorial investigation of novel moisturizers and pharmaceutical vehicles should be further conducted. As a new concept for improving skin moisturization, skin regeneration technologies using therapeutic cells have recently shown great promise for skin moisturization, but major challenges remain, such as efficient delivery and prolonged survival of such cells. Thus, novel approaches for improving skin moisturization require continuous efforts of pharmaceutical scientists to address the remaining problems.

The ocean contains numerous marine organisms, including algae, animals, and plants, from which diverse marine polysaccharides with useful physicochemical and biological properties can be extracted. In particular, fucoidan, carrageenan, alginate, and chitosan have been extensively investigated in pharmaceutical and biomedical fields owing to their desirable characteristics, such as biocompatibility, biodegradability, and bioactivity. Various therapeutic efficacies of marine polysaccharides have been elucidated, including the inhibition of cancer, inflammation, and viral infection. The therapeutic activities of these polysaccharides have been demonstrated in various settings, from in vitro laboratory-scale experiments to clinical trials. In addition, marine polysaccharides have been exploited for tissue engineering, the immobilization of biomolecules, and stent coating. Their ability to detect and respond to external stimuli, such as pH, temperature, and electric fields, has enabled their use in the design of novel drug delivery systems. Thus, along with the promising characteristics of marine polysaccharides, this review will comprehensively detail their various therapeutic, biomedical, and miscellaneous applications.

In this study, we examined the effect of pharmaceutical excipients preferred in lipid-based formulations for lymphatic delivery on in vitro association of probucol with chylomicron (CM). CM stability study was performed under the conditions of room temperature, refrigeration and deep freezing to optimize the storage condition of CM dispersion prior to CM-binding study. The mean particle size, size distribution and zeta potential value were considerably maintained for 48 h under the refrigeration condition. CM-binding study was conducted using probucol incorporated in vehicles composed of solubilizer (Transcutol HP or ethanol or propylene glycol) or surfactant (Tween-80 or Tween-20 or Cremophor ELP), and CM dispersion obtained by a density-gradient ultracentrifugation. Levels of the association of probucol with CM were largely governed by solubility of probucol in pharmaceutical excipients tested in this study, and the ability of solubilizers tested to enhance the affinity of probucol with CM was much greater than that of surfactants tested. Furthermore, the association of probucol with CM was enhanced by increasing the amount of the drug solubilized in propylene glycol or Transcutol HP. Together, the result of this CM-binding study showed that solubilizers tested in this study can increase levels of the association of probucol with CM, potentially leading to an increase in lymphatic exposure of drugs. Thus, identifying pharmaceutical excipients having better solubilizing ability would be advantageous for enhanced lymphatic delivery.

As an initial step to develop the transdermal delivery system of glucosamine hydrochloride (GL-HCl), the permeation study across the rat skin in vitro was performed to identify the most efficient vehicle with regard to the ability to deliver GL-HCl transdermally. The GL-HCl formulations such as o/w cream, liposome suspension, liposomal gel, and liquid crystalline vehicles were prepared and compared for transdermal flux of GL-HCl. The liquid crystalline vehicles were more effective in increasing the skin permeation of GL-HCl than o/w cream and liposomal vehicles. Of the liquid crystalline vehicles tested, the permeation enhancing ability of the cubic phase was greater than that of the hexagonal phase when the nanoparticle dispersion was used. The skin permeation enhancing ability of the cubic nanoparticles for GL-HCl was further increased by employing both oleic acid and polyethylene glycol 200. Therefore, the cubic liquid crystalline nanodispersion containing oleic acid and PEG 200 can provide a possibility of clinical application of transdermal GL-HCl.

To enhance skin permeation of ascorbyl palmitate (AsP), it was encapsulated in liposomes, and formulated into liposomal hydrogel (lipogel) by dispersing the liposome into poloxamer hydrogel matrix. To improve the skin permeation of AsP, we applied electric current supplying system that mimics an electric skin massager. We evaluated the effects of composition and surface charge of the liposomes and electrical assistance on the skin permeation of AsP. In the passive transport study, the permeated amounts of AsP from all the lipogels tested were higher than that of control hydrogel which contains Transcutol used to solubilize AsP. In the cathodal delivery condition with a fixed cathodal current of 0.4 mA/cm2, the skin permeation characteristics of the negative lipogels were superior to that obtained with the neutral lipogels and the drug permeation was more increased with increased surface negative charge of the liposomes. In conclusion, the lipogel system was thought as a helpful drug delivery system to enhance skin permeation of AsP. Combined use of negative lipogel with cathodal electric assistance was found to be promising in enhancing the skin delivery of AsP.

Hydrotropic polymer micelle system has been developed for delivery of poorly water-soluble drugs such as paclitaxel. Hydrotropic polymers based on N,N-diethylnicotinamide were synthesized and used as a hydrophobic block for constructing amphiphilic block copolymers. The hydrotropic block copolymers self-assembled to form micelles in aqueous media. The size of the prepared polymer micelles was in the range of 30-50 nm, and increased to 100-120 nm after paclitaxel loading. The critical micelle concentrations (CMCs) of the block copolymers were higher by an order of magnitude than those of other typical polymer micelles, due to less hydrophobicity of the hydrotropic blocks. The drug loading capacity and physical stability of the polymer micelles were characterized and compared with those of other polymer micelles. The hydrotropic polymer micelles containing hydrotrope-rich cores showed not only higher loading capacity but also enhanced physical stability in aqueous media. They could be redissolved in aqueous media by simple vortexing and/or a mild heating. The hydrotropic polymer micelles provide an alternative approach for formulation of poorly soluble drugs.

The purpose of this study is to investigate the recoverability of freeze-dried chitosan microspheres (MS). The factors influencing the integrity of chitosan MS during freeze-drying and rehydration procedures were determined, with focusing on choosing a suitable rehydration method and a freeze-drying excipient. Mean MS size, size distribution and sphericity of recovered chitosan MS were evaluated. Furthermore, the impacts of freeze-drying and rehydration procedure on the elasticity of chitosan MS were explored and the release profiles were evaluated. The recoverability of lyophilized chitosan MS was largely dependent on rehydration method and freeze-drying excipients. When using the optimized recovery processes, deformable drug-loaded chitosan MS can be rapidly recovered to exhibit the initial physicomechanical properties such as elasticity. Release profiles also were not significantly changed after rehydration procedure. It is therefore expected drug-loaded chitosan MS can be stably freeze-dried with the prevention of drug release during storage and rapidly recovered to be used as deformable embolic materials possibly applicable for anti-cancer embolotherapy. [ABSTRACT FROM AUTHOR]

Background: Drug release from a solid form of self-emulsifying drug delivery system (SEDDS) has greatly been limited due to strong adsorption and physical interaction with carriers. To facilitate drug release process in the stomach, an acid-soluble powderizing carrier, Fujicalin® was evaluated together with different disintegrants and hydrophilic lubricants. Method: Immediate-release self-emulsifying tablets (IR-SETs) of ibuprofen (IBU) was prepared with solidified SEDDS of IBU, various disintegrants, and lubricants, and drug release was evaluated to develop IR-SET that can release IBU with a similar IBU release rate to that obtained with liquid SEDDS. Results: The liquid SEDDS consisted of Capryol 90, Cremophor EL, Labrasol, and IBU at a ratio of 3:4:3:3, and was solidified with various adsorbents. The powderized SEDDS was tabletted by a direct compression. Fujicalin®-based SEDDS tablets demonstrated remarkably higher dissolution rate of IBU compared with Neusilin® and Neosyl®-based SEDDS tablets. The IR-SET formula of IBU prepared with Fujicalin® as an adsorbent, Polyplasdone® as a disintegrant, and sodium bicarbonate as a co-disintegrant showed over 90% of initially loaded dose of IBU released within 5 min in a stimulated gastric juice (pH 1.2), exhibiting almost equivalent rate of IBU release to that shown by liquid SEDDS. The particle size analysis revealed no significant differences in droplet sizes of the microemulsions formed from liquid (116 nm) and IR-SET (110 nm). Conclusion: The novel IR-SET can be promising as a fast-releasing SEDDS tablet of IBU for fast onset of action. [ABSTRACT FROM AUTHOR]

In order to facilitate the intracellular delivery of macromolecules, Pep-1 peptide-modified liposomal (Pep1-Lipo) nanocarriers were designed and examined for their in vitro cell translocation capability. Pep-1 peptides were coupled via thiol-maleimide linkage to small unilamellar vesicles composed of phosphatidylcholine, Tween 80, and N-[4-(p-maleimidophenyl)butyryl]-phosphatidylethanolamine (MPB-PE). The amount of Pep-1 peptide conjugated to the vesicle was effectively controlled by the amounts of maleimide groups on the vesicular surface, ranging from 70 to 700 molecules per vesicle. Systems were evaluated for cell uptake capacity by monitoring entrapped fluorescence-labeled bevacizumab, a model protein for poorly permeable macromolecule, using confocal microscopy. The novel carriers rapidly bound to the cell membrane and migrated into the cells within 1 h, exhibiting better translocation of macromolecules compared to that of conventional liposomes. Cellular uptake of Pep1-Lipo was proportional to the amount of Pep-1 peptide on the liposomal surface. In conclusion, we found that the Pep1-Lipo formulation was a promising nanocarrier system for intracellular delivery of macromolecules. [ABSTRACT FROM AUTHOR]

Simultaneous evaluation of the permeation and washout of a peptide from the mucoadhesive liquid crystalline phases of glyceryl monooleate (GMO) has been investigated using a donor compartment flow-through diffusion cell. [d-Ala2, d-Leu5]enkephalin (DADLE) was incorporated into the cubic and lamellar liquid crystalline phases of GMO and applied to excised porcine buccal mucosa mounted in the donor compartment flow-through cell. Phosphate-buffered saline pH 7.4 (PBS) was pumped across the upper surface of the liquid crystalline phases to mimic salivary flow. The steady-state fluxes of DADLE and GMO from the cubic phase were significantly greater than that from the lamellar phase (P<0.01). There was no statistical difference between the amounts of DADLE and GMO washed out from the lamellar and cubic phases (P>0.05). The donor compartment flow-through diffusion cell was found to be a useful tool to evaluate the impact of salivary washout on mucoadhesive oral mucosal delivery systems. [ABSTRACT FROM AUTHOR]

This study aimed to design phosphatidylcholine (PC)-based solid dispersion (SD) systems for enhancing the apparent aqueous solubility and dissolution of celecoxib (CLC), a selective cyclooxygenase-2 inhibitor with a highly hydrophobic property. Although PC-based dispersion formulations considerably increased solubilities of CLC, the lipidic texture of PC was not appropriate as a solid dosage form for oral administration of CLC. To mask the lipidic texture of PC-based matrices, Neusilin® US2, an adsorbent material with a porous structure and large surface area widely used in the pharmaceutical industry, was employed and thereby fully powderized PC-based dispersion formulations could be fabricated. However, PC matrices containing CLC strongly adsorbed to the pores of Neusilin® US2 was not able to be rapidly released. To address this problem, different hydrophilic materials were examined to promote the release of the CLC-dispersed PC matrices from Neusilin® US2. Among tested hydrophilic materials, croscarmellose sodium was the most suitable to facilitate fast drug dissolution from Neusilin® US2 particles, showing significantly enhanced apparent aqueous solubility and dissolution behavior of CLC. Through differential scanning calorimetry, X-ray diffraction, and Fourier transform infrared spectroscopy (FT-IR) analysis, a considerably reduced crystallinity of CLC dispersed in the PC-based dispersion formulations was demonstrated. The PC-based SD formulations developed in this study would be useful for improving the oral bioavailability of poorly soluble drugs such as CLC. [ABSTRACT FROM AUTHOR]

Abstract: Sustained release (SR) tablets containing solid dispersions (SD) granules of a poorly water-soluble drug were prepared to investigate the controlled pH-independent release of the drug. Losartan potassium (LST), an anti-hypertensive agent was chosen as a model drug because of its pH-dependent solubility and short elimination half-life. Poloxamer 188 was used as an SD carrier. A free-flowing SD granule was prepared by adsorbing the melt of the drug and poloxamer 188 onto the surface of an adsorbent, Aerosil 300 (fumed silicon dioxide), followed by direct compression with polyethylene oxide (PEO, 5×106) to obtain an SD-loaded SR (SD-SR) matrix tablet. Differential scanning calorimetry (DSC) and powder X-ray diffraction (PXRD) revealed partially amorphous structures of the drug in the SD granules. Scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) images indicated adsorption of SD granules onto the surface of the adsorbent. The SD granules dissolved completely within 10min, a dissolution rate much higher than that of pure LST. Moreover, pH-independent sustained release of LST from the SD-SR tablet was achieved for 2h in gastric fluid (pH 1.2) and for 10h in intestinal fluid (pH 6.8). A combination of SD techniques using surface adsorption and SR concepts is a promising approach to control the release rate of poorly water-soluble drugs in a pH-independent manner. [Copyright &y& Elsevier]