Generating Lifetime-Enhanced Microbubbles by Decorating Shells with Silicon Quantum Nano-Dots Using a 3-Series T-Junction Microfluidic Device

Long-term stability of microbubbles is crucial to their effectiveness. Using a new microfluidic device connecting three T-junction channels of 100 μm in series, stable monodisperse SiQD-loaded bovine serum albumin (BSA) protein microbubbles down to 22.8 ± 1.4 μm in diameter were generated. Fluorescence microscopy confirmed the integration of SiQD on the microbubble surface, which retained the same morphology as those without SiQD. The microbubble diameter and stability in air were manipulated through appropriate selection of T-junction numbers, capillary diameter, liquid flow rate, and BSA and SiQD concentrations. A predictive computational model was developed from the experimental data, and the number of T-junctions was incorporated into this model as one of the variables. It was illustrated that the diameter of the monodisperse microbubbles generated can be tailored by combining up to three T-junctions in series, while the operating parameters were kept constant. Computational modeling of microbubble diameter and stability agreed with experimental data. The lifetime of microbubbles increased with increasing T-junction number and higher concentrations of BSA and SiQD. The present research sheds light on a potential new route employing SiQD and triple T-junctions to form stable, monodisperse, multi-layered, and well-characterized protein and quantum dot-loaded protein microbubbles with enhanced stability for the first time

Understanding the mechanism of Curcumin Eutectics/Cocrystal formation with Salicylic acid and Hydroxyquinol

by Indumathi Sathisaran and Sameer V. Dalv

Understanding morphological evolution of Griseofulvin particles into hierarchical microstructures during liquid antisolvent precipitation

Controlling morphology of active pharmaceutical ingredients (APIs) during crystallization/precipitation is essential for pharmaceutical development since the pharmaceutical powder properties such as solubility, flowability, and dissolution rates are morphology dependent. The objective of this work was to understand the morphological evolution of a poorly water-soluble antifungal drug, griseofulvin (GF), during liquid antisolvent (LAS) precipitation in the presence of ultrasound and additives. GF was found to precipitate as hierarchical structures in the presence of different additives and in the absence of ultrasound. An umbrella-like morphology was observed when hydroxypropyl methylcellulose was used, hexagonal particles elongated along the central axis were obtained in the presence of Tween 80, and the use of polyvinylpyrrolidone yielded long needle-like particles. The most fascinating morphology was observed in the case of bovine serum albumin and no ultrasound, where the GF particles precipitated as six-branched hierarchical structures. Interestingly, the morphology of 6-month-old GF particles reveals that the outline of the overall morphology of initial unfilled skeletons resembled the bipyramidal morphology that would form when particles are completely filled/fused due to Ostwald ripening. The size of GF particles typically varied from 30 to 50 ?m when no ultrasound was used. Time-resolved scanning electron microscopy (SEM) studies imply that interesting morphologies of GF particles observed in the absence of ultrasound could be the result of aggregation and fusion of a large number of small particles formed in the beginning of the precipitation process. These smaller particles fuse to form primary bipyramidal particles which then undergo diffusion-limited growth through Ostwald ripening and secondary nucleation on specific particle faces due to selective adsorption of additives depending on the functional groups present on those particular faces. In contrast to the no ultrasound situation, the use of ultrasound along with the additives resulted in the formation of completely filled octahedron/bipyramidal GF particles irrespective of the additive used. These particles were significantly smaller with sizes ranging from 4 to 6 ?m. Use of ultrasound improves micromixing and alters the particle growth mechanism from diffusion limited to integration controlled resulting in smaller and well-formed GF particles.by Rupanjali Prasad and Sameer V. Dalv

Understanding evolution Of hierarchical structures of a poorly water soluble drug using additives during liquid antisolvent precipitation

by Rupanjali Prasad and Sameer V.Dalv

Investigation of carbamazepine-para hydrozybenzamide cocrystallization for enhanced aqueous solubility

by Indumathi Sathisaran and Sameer V. Dalv

Understanding the interactions of additives and stabilization of fenofibrate particles in aqueous suspensions

by Komal Pandey and Sameer V. Dalv

Enhancing aqueous solubility of carbamazepine by crystal engineering approach

by Indumathi Sathisaran and Sameer V. Dalv

Engineering cocrystals of poorly water-soluble drugs to enhance dissolution in aqueous medium

Biopharmaceutics Classification System (BCS) Class II and IV drugs suffer from poor aqueous solubility and hence low bioavailability. Most of these drugs are hydrophobic and cannot be developed into a pharmaceutical formulation due to their poor aqueous solubility. One of the ways to enhance the aqueous solubility of poorlywater-soluble drugs is to use the principles of crystal engineering to formulate cocrystals of these molecules with water-soluble molecules (which are generally called coformers). Many researchers have shown that the cocrystals significantly enhance the aqueous solubility of poorly water-soluble drugs. In this review, we present a consolidated account of reports available in the literature related to the cocrystallization of poorly water-soluble drugs. The current practice to formulate new drug cocrystals with enhanced solubility involves a lot of empiricism. Therefore, in this work, attempts have been made to understand a general framework involved in successful (and unsuccessful) cocrystallization events which can yield different solid forms such as cocrystals, cocrystal polymorphs, cocrystal hydrates/solvates, salts, coamorphous solids, eutectics and solid solutions. The rationale behind screening suitable coformers for cocrystallization has been explained based on the rules of five i.e., hydrogen bonding, halogen bonding (and in general non-covalent bonding), length of carbon chain, molecular recognition points and coformer aqueous solubility. Different techniques to screen coformers for effective cocrystallization and methods to synthesize cocrystals have been discussed. Recent advances in technologies for continuous and solvent-free production of cocrystals have also been discussed. Furthermore, mechanisms involved in solubilization of these solid forms and the parameters influencing dissolution and stability of specific solid forms have been discussed. Overall, this review provides a consolidated account of the rationale for design of cocrystals, past efforts, recent developments and future perspectives for cocrystallization research which will be extremely useful for researchers working in pharmaceutical formulation development.by Indumathi Sathisaran and Sameer Vishvanath Dalv

Current trends in academic research in chemical engineering

by Jyot Antani and Sameer V. Dalv

Engineering heat and mass transfer

by Narsipur V. Suryanarayana and Sameer V. Dalv