Development and Evaluation of Sunscreen Cream Containing Benzophenone-3 Microspheres for Enhancing Sunscreen Activity

In present work, sunscreen cream containing Benzophenone – 3 microspheres were prepared and an attempt were made to deliver sunscreening agent in sustained release manner from microspheres containing cream. Microspheres are prepared by emulsion cum thermal gelation technique and the o/w emulsion was selected as cream. Optimized batch of microspheres were taken and mixed with cream. This cream was subjected to determination of various parameters like color, pH, rancidity, viscosity, spreadability and extrudability. In vitro drug release study and SPF were determined. Cream has also been evaluated for in vivo ocular toxicity testing, skin irritancy testing, testing for sensitizing potential, and photosensitivity test. Results revealed that no ocular irritation and skin irritation occurs. Physical stability and chemical stability were tested. Sunscreen cream is homogeneous, smooth on application, having good spreadability and extrudability and milky white in color. The pH was found to be 7.1. Cream shows viscosity 32840 cps, no rancidity and no phase separation on centrifugation were observed. In vitro drug release study revealed that both 1% and 2% microspheres containing cream follow zero order release kinetics which means release rate was found constant. In vitro SPF was evaluated mean SPF of 1% cream was 13.74 and mean SPF of 2% cream was 31.47. Physical stability testing revealed that cream was not greatly affected by various stress conditions like freeze-thaw (-5 to +5°C), shaking (100-500 rpm) and centrifugation (1000-5000 rpm) except 5000 rpm. Results of chemical stability revealed that the formulations exhibited good stability at elevated temperature between 25-45°C and slight changes may occur which are reversible in nature. In present work attempt were made to develop microspheres containing sunscreen cream and it was characterized for various parameters. Sunscreen cream was safe and effective and also showed sustain drug release.

Thermal Gelation for Synthesis of Surface-Modified Silica Aerogel Powders

A spherical silica aerogel powder with hydrophobic surfaces displaying a water contact angle of 147° was synthesized from a water glass-in-hexane emulsion through ambient pressure drying. Water glass droplets containing acetic acid and ethyl alcohol were stabilized in n-hexane with a surfactant. Gelation was performed by heating the droplets, followed by solvent exchange and surface modification using a hexamethyldisilazane (HMDS)/n-hexane solution. The pH of the silicic acid solution was crucial in obtaining a highly porous silica aerogel powder with a spherical morphology. The thermal conductivity, tapped density, pore volume, and BET surface area of the silica aerogel powder were 22.4 mW·m−1K−1, 0.07 g·cm−3, 4.64 cm3·g−1, and 989 m2·g−1, respectively. Fourier transform infrared (FT–IR) spectroscopy analysis showed that the silica granule surface was modified by Si-CH3 groups, producing a hydrophobic aerogel.

Photocrosslinkable liver extracellular matrix hydrogels for the generation of 3D liver microenvironment models

Liver extracellular matrix (ECM)-based hydrogels have gained considerable interest as biomimetic 3D cell culture environments to investigate the mechanisms of liver pathology, metabolism, and toxicity. The preparation of current liver ECM hydrogels, however, is based on time-consuming thermal gelation and limits the control of mechanical properties. In this study, we used detergent-based protocols to produce decellularized porcine liver ECM, which in turn were solubilized and functionalized with methacrylic anhydride to generate photocrosslinkable methacrylated liver ECM (LivMA) hydrogels. Firstly, we explored the efficacy of two protocols to decellularize porcine liver tissue using varying combinations of commonly used chemical agents such as Triton X-100, Sodium Dodecyl Sulphate (SDS) and Ammonium hydroxide. Then, we demonstrated successful formation of stable, reproducible LivMA hydrogels from both the protocols by photocrosslinking. The LivMA hydrogels obtained from the two decellularization protocols showed distinct mechanical properties. The compressive modulus of the hydrogels was directly dependent on the hydrogel concentration, thereby demonstrating the tuneability of mechanical properties of these hydrogels. Immortalized Human Hepatocytes cells were encapsulated in the LivMA hydrogels and cytocompatibility of the hydrogels was demonstrated after one week of culture. In summary, the LivMA hydrogel system provides a simple, photocrosslinkable platform, which can potentially be used to simulate healthy versus damaged liver for liver disease research, drug studies and cancer metastasis modelling.

Aqueous Triple-Phase System in Microwell Array for Generating Uniform-Sized DNA Hydrogel Particles

DNA hydrogels are notable for their biocompatibility and ability to incorporate DNA information and computing properties into self-assembled micrometric structures. These hydrogels are assembled by the thermal gelation of DNA motifs, a process which requires a high salt concentration and yields polydisperse hydrogel particles, thereby limiting their application and physicochemical characterization. In this study, we demonstrate that single, uniform DNA hydrogel particles can form inside aqueous/aqueous two-phase systems (ATPSs) assembled in a microwell array. In this process, uniform dextran droplets are formed in a microwell array inside a microfluidic device. The dextran droplets, which contain DNA motifs, are isolated from each other by an immiscible PEG solution containing magnesium ions and spermine, which enables the DNA hydrogel to undergo gelation. Upon thermal annealing of the device, we observed the formation of an aqueous triple-phase system in which uniform DNA hydrogel particles (the innermost aqueous phase) resided at the interface of the aqueous two-phase system of dextran and PEG. We expect ATPS microdroplet arrays to be used to manufacture other hydrogel microparticles and DNA/dextran/PEG aqueous triple-phase systems to serve as a highly parallel model for artificial cells and membraneless organelles.

Silver Nanoparticles as an Effective Antimicrobial against Otitis Media Pathogens

Otitis Media (OM) is the most common reason for U.S. children to receive prescribed oral antibiotics, leading to potential to cause antibiotic resistance. To minimize oral antibiotic usage, we developed polyvinylpyrrolidone-coated silver nanoparticles (AgNPs-PVP), which completely eradicated common OM pathogens, i.e., Streptococcus pneumoniae and non-typeable Haemophilus influenzae (NTHi) at 1.04µg/mL and 2.13µg/mL. The greater antimicrobial efficacy against S. pneumoniae was a result of the HO-producing ability of S. pneumoniae and the known synergistic interactions between HO and AgNPs. To enable the sustained local delivery of AgNPs-PVP (e.g., via injection through perforated tympanic membranes), a hydrogel formulation of 18%(w/v)P407 was developed. Reverse thermal gelation of the AgNPs-PVP-P407 hydrogel could gel rapidly upon entering the warm auditory bullae and thereby sustained release of antimicrobials. This hydrogel-based local delivery system completely eradicated OM pathogens in vitro without cytotoxicity, and thus represents a promising strategy for treating bacterial OM without relying on conventional antibiotics.

Current Status of Mucoadhesive Gel Systems for Buccal Drug Delivery

Background: Buccal drug delivery is a fascinating research field. Gel-based formulations present potent characteristics as buccal systems since they have great physicochemical properties. Methods: Among the various gels, in situ gels that are viscous colloidal systems consisted of polymers when physiological conditions change (pH, temperature, ion activation) shift to the gel phase. These systems can improve bioavailability. Other systems such as nanogels or emulgels can be also applied for buccal delivery with promising results. Polymeric gel-based systems can be produced by natural, semisynthetic, and synthetic polymers. Their main advantage is that the active molecules can be released in a sustained and controllable manner. Several gels based on chitosan are produced for the entrapment of drugs demonstrating efficient retention time and bioavailability, due to chitosan mucoadhesion. Besides polysaccharides, poloxamers and Carbopol are also used in buccal gels due to their high swelling ability and reversed thermal gelation behavior. Results: Herein, the authors focused on the current development of mucoadhesive gel systems used in buccal drug delivery. After explaining buccal drug delivery and mucoadhesion, various studies with hydrogels, in situ gels, and nanogels were analyzed as buccal gel systems. Various mucoadhesive gel studies with mucoadhesive polymers have been studied and summarized. This review is presented as valuable guidance to scientists in formulating buccal mucoadhesive drug delivery systems. Conclusions: This review aimed to assist researchers working on buccal drug delivery by summarizing buccal drug delivery, mucoadhesion, and buccal mucoadhesive gel systems recently found in the literature.