Using Zeolite-Zirconia-Copper Nanocomposites as a New Asphaltene Inhibitor for Improving Permeability Reduction during CO 2 Flooding

Using nanoparticles for adsorbing asphaltene was known as an efficient method among researchers for crude oil upgrading and in this study, Zeolite-zirconia-copper nanocomposites (NCs) has been synthesized and characterized with SEM, XRD, BET, and EDX for asphaltene precipitation inhibition in the static phase and solving asphaltene deposition problems of dynamic CO2 flooding in low permeability carbonate reservoir. CO2-oil IFT tests, isotherm models, natural depletion tests at static phase were performed in the presence of NCs and the results were compared with zeolite nanoparticles. Then, CO2 core flooding tests at dynamic phase were designed in the presence of NCs at obtained static conditions for surveying permeability/porosity reduction in porous media. After adding NCs and zeolite nanoparticles, the 2nd to 1st slope ratio in CO2-oil IFT tests increased from 19.697 % to 20.895 % and 29.851 %, respectively which shows NCs adsorbed more asphaltene in comparison to zeolite nanoparticles which confirmed UV-Vis results. NCs was decreased asphaltene precipitation more than zeolite at same points during natural depletion tests and it was selected for dynamic CO2 tests. After adding NCs, asphaltene depositions which occurs after CO2 injection was decreased and permeability/porosity reduction parameters were improved.

Small but effective: light-weight additives modulate prenucleation clusters by specific interactions on the molecular level

Small-molecular-weight (MW) additives can strongly impact amorphous calcium carbonate (ACC), playing an elusive role in biogenic, geologic, and industrial calcification. Here, we present molecular mechanisms by which additives regulate stability and composition of solid ACC and CaCO3 solutions simultaneously. Effective precipitation inhibition arises from pronounced interaction of additives with prenucleation clusters (PNC). Potent antiscalants specifically trigger and integrate into PNCs. Only PNC-interacting additives are traceable in solid ACC, considerably stabilizing ACC against transformation. This co-precipitation specificity facilitates a chemical labeling of PNCs, evidencing ACC as a molecular precipitate of PNCs. Our results reveal additive-cluster interactions that operate beyond established mechanistic conceptions and thus reassess the role of small-MW molecules in crystallization and especially in biomineralization while breaking grounds for new sustainable antiscalants.

Novel in vitro and in silico tools for the development of mesoporous silica formulations with optimal precipitation inhibitors

Formulation scientists have developed a toolkit of strategies that can improve the solubility and subsequent bioavailability of poorly soluble candidates. Amorphous formulations are especially appealing due to the significant improvement in solubility the amorphous form can provide, but must be stabilized for effective performance (Timpe, 2007). 2. The Importance of Drug Polymer Interactions in Precipitation Inhibition Polymeric “precipitation inhibitors” have seen widespread usage in the literature (Warren, 2010). The precipitation inhibition effect of polymers on precipitations is related to interference with nucleation and crystal growth (Xu, 2013). Many techniques have been reported in the literature to predict these interactions, however, they are not suitable to screening due to API and time resources required, which are not amenable to early stage pharmaceutical development. 3. Mesoporous Silica: An Emerging Formulation Technology Mesoporous silicon dioxide has emerged in recent years as a new option for stabilizing the amorphous form. Upon impregnation of the silica with a concentrated drug solution, the drug can be molecularly adsorbed and locally and sterically confined, preventing recrystallization (Ditzinger, 2018). Upon administration of mesoporous silica formulations to the body the amorphous formulation generates supersaturation which must be stabilized using precipitation inhibitors (Guzman, 2007). 4. Co-incorporation: A New Method to Combine Precipitation Inhibitors with Mesoporous Silica There has been no systematic study of how best to incorporate precipitation inhibitors into mesoporous silica formulations. The current standard practice involves combining inhibitors in a physical mixture with the drug-loaded silica, either by pestle and mortar or overhead stirring. Due to the lack of a defined protocol, there is uncertainty about how reliably the precipitation inhibitor is combined with the drug-loaded silica on a batch to batch basis. In this work, a novel co-incorporated formulation of glibenclamide and the precipitation inhibitor, HPMCAS, onto mesoporous silica was described. By co-incorporating the precipitation inhibitor, the formulation significantly outperformed the commonly applied simple physical blend due to the formation of drug-polymer interactions in the solid state. 5. In Silico Pharmaceutics: A New Method to Select Precipitation Inhibitors for Mesoporous Silica An approach that can incorporate understanding of the drug-polymer interactions with a quick and efficient screening process would be very useful. The COnductor like Screening MOdel for Real Solvents (COSMO-RS) is a quantum mechanical theory, which can be used to derive thermodynamic properties of interest. (Klamt, 1993, 1995, 2003). We proposed excess mixing enthalpies of drug and polymer could be calculated using the COSMO-RS theory. This new approach was applied to screen precipitation inhibitors for three model compounds, all of which showed a strong positive correlation between the rank assigned based on the calculated free enthalpy of mixing and the overall formulation performance. 6. Conclusion This body of work aimed to improve the processes underpinning the design and development of mesoporous silica with precipitation inhibitors. Firstly, this involved two extensive literature reviews in the area of solubility enhancement formulation technologies and precipitation inhibition. Secondly, a mechanistic rational and experimental approach was developed to improve the formulation of precipitation inhibitors with mesoporous silica, the “co-incorporation” approach significantly improved process efficiency and formulation performance. Finally, combining insights from the aforementioned review, and learnings from the mechanistic analysis of the “co-incorporation” approach, an in silico screening protocol was developed to calculate the enthalpy of interaction between drug and polymer, to identify the most optimal precipitation inhibitor for a given formulation.

Comparison Between Conventional and Supersaturable Self-nanoemulsion Loaded with Nebivolol: Preparation and In-vitro/Ex-vivo Evaluation

Nebivolol (NBH) is a third-generation B1-blocker with high selectivity and vasodilation activity. Nevertheless, nebivolol exhibits low oral bioavailability, which may adversely affect its efficacy. Recently, supersaturable self-nanoemulsion (Su-SNE) is an advanced SNE approach that can address low bioavailability The study aims to prepare nebivolol-loaded Su-SNE by reduction the amount of the prepared conventional SNE to half. Besides, an appropriate polymer type and concentration to prevent NBH precipitation upon oral administration have investigated.. A conventional self-nanoemulsion (formula A) was prepared by dissolving NBH in 500 mg vehicle mixture of imwitor®988: cremophor-EL: propylene glycol. Then, eight Su-SNE formulas with the absence or presence of four different polymers were prepared and evaluated. In-vitro precipitation assay was performed to assess the precipitation inhibition capacity of polymers. The ex-vivo permeation through rat intestinal mucosa was also conducted for determination of permeability parameters. Results revealed that (Su-SNA formula SAS1) containing 5% soluplus could effectively retard the nebivolol precipitation. There was no statistical difference between formula A and SAS1; both maintained a higher apparent NBH concentra­tion for approximately 240 min in 0.1N HCl. The permeation rate of conventional (formula A) and soluplus-based Su-SNE (formula SAS1) was significantly improved, and the permeation enhancement ratio was found 2.7 and 3.2, respectively, as compared with non-formulated NBH. Consequently, it is concluded that developing soluplus-based nebivolol SNE is a promising alternative approach. It can enhance nebivolol stability and permeability with half the amount of conventional SNE components.