The low water solubility of pharmacoactive molecules limits their pharmacological potential, but the solubility parameter cannot compromise, and so different approaches are employed to enhance their bioavailability. Pharmaceutically active molecules with low solubility convey a higher risk of failure for drug innovation and development. Pharmacokinetics, pharmacodynamics, and several other parameters, such as drug distribution, protein binding and absorption, are majorly affected by their solubility. Among all pharmaceutical dosage forms, oral dosage forms cover more than 50%, and the drug molecule should be water-soluble. For good therapeutic activity by the drug molecule on the target site, solubility and bioavailability are crucial factors. The pharmaceutical industry’s screening programs identified that around 40% of new chemical entities (NCEs) face various difficulties at the formulation and development stages. These pharmaceuticals demonstrate less solubility and bioavailability. Enhancement of the bioavailability and solubility of drugs is a significant challenge in the area of pharmaceutical formulations. According to the Classification of Biopharmaceutics, Class II and IV drugs (APIs) exhibit poor solubility, lower bioavailability, and less dissolution. Various technologies are discussed in this article to improve the solubility of poorly water-soluble drugs, for example, the complexation of active molecules, the utilization of emulsion formation, micelles, microemulsions, cosolvents, polymeric micelle preparation, particle size reduction technologies, pharmaceutical salts, prodrugs, the solid-state alternation technique, soft gel technology, drug nanocrystals, solid dispersion methods, crystal engineering techniques and nanomorph technology. This review mainly describes several other advanced methodologies for solubility and bioavailability enhancement, such as crystal engineering, micronization, solid dispersions, nano sizing, the use of cyclodextrins, solid lipid nanoparticles, colloidal drug delivery systems and drug conjugates, referring to a number of appropriate research reports.

Conventional thin film composite (TFC) nanofiltration (NF) membranes are positively or negatively charged with an active layer thickness of several nanometers depending on the preparation conditions. Low molecular weight cutoff (MWCO) ultrafiltration (UF) membranes obtained by the phase inversion process show low permeate flux due to the formation of a several micrometre thick skin layer. We have developed an extremely simple route to produce novel TFC NF (MCO∼180 Da) and UF (MWCO∼1 and 10 kDa) types of membranes with an active layer thickness in the range of 12–36 nm via supported interfacial polymerization using polyethyleneimine (PEI) as a monomer. The membrane charge, solute rejection, active layer thickness, and MWCO have been modulated by simple adjustment of diffusion of PEI towards the interfacial zone. TFC UF type of membranes were formed at PEI concentrations in the range of 0.01–0.03% w/v while NF membranes were formed at PEI concentrations in the range of 0.05–0.3% w/v. Our TFC NF membranes exhibited a permeate water flux of 19–24 L m⁻² h⁻¹ bar⁻¹ which is about 4–5 times higher than those of PEI-based membranes and 1.3–4 times higher than those of a few commercial NF membranes of similar MWCOs. The TFC UF membranes showed a permeate flux of ca. 48–69 L m⁻² h⁻¹ bar⁻¹, about 2–5 times higher than those of some UF membranes reported here. The process is scalable, and the membranes are useful for the separation of charge and neutral solutes with high efficiency.

The global energy market is shifting toward renewable, sustainable, and low-carbon hydrogen energy due to global environmental issues, such as rising carbon dioxide emissions, climate change, and global warming. Currently, a majority of hydrogen demands are achieved by steam methane reforming and other conventional processes, which, again, are very carbon-intensive methods, and the hydrogen produced by them needs to be purified prior to their application. Hence, researchers are continuously endeavoring to develop sustainable and efficient methods for hydrogen generation and purification. Membrane-based gas-separation technologies were proven to be more efficient than conventional technologies. This review explores the transition from conventional separation techniques, such as pressure swing adsorption and cryogenic distillation, to advanced membrane-based technologies with high selectivity and efficiency for hydrogen purification. Major emphasis is placed on various membrane materials and their corresponding membrane performance. First, we discuss various metal membranes, including dense, alloyed, and amorphous metal membranes, which exhibit high hydrogen solubility and selectivity. Further, various inorganic membranes, such as zeolites, silica, and CMSMs, are also discussed. Major emphasis is placed on the development of polymeric materials and membranes for the selective separation of hydrogen from CH₄, CO₂, and N₂. In addition, cutting-edge mixed-matrix membranes are also delineated, which involve the incorporation of inorganic fillers to improve performance. This review provides a comprehensive overview of advancements in gas-separation membranes and membrane materials in terms of hydrogen selectivity, permeability, and durability in practical applications. By analyzing various conventional and advanced technologies, this review provides a comprehensive material perspective on hydrogen separation membranes, thereby endorsing hydrogen energy for a sustainable future.