Basic Concepts of Theory of Phase Transformations

Ovrutsky, A.M.; Prokhoda, A.S.; Rasshchupkyna, M.S.

doi:10.1016/b978-0-12-420143-9.00002-8

Cited by 7 publications

(5 citation statements)

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“…The rapid crystallization dominated massively in the long-chain fatty acid solution. Theoretically, an energy exists at the boundary between any unmixable objects; this energy can provoke nucleation and subsequently, crystallization through a thermodynamic driving force [ 66 ]. Thence, not only the external interface comprising agarose and initial crystal interface but also the interface of unmixed liquids can induce continuous crystallization.…”

Section: Resultsmentioning

confidence: 99%

Saturated Fatty Acid-Based In Situ Forming Matrices for Localized Antimicrobial Delivery

et al. 2020

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In recent years, the world has faced the issue of antibiotic resistance. Methicillin-resistant Staphylococcus aureus (MRSA) is a significant problem in various treatments and control of infections. Biocompatible materials with saturated fatty acids of different chain lengths (C8–C18) were studied as matrix formers of localized injectable vancomycin HCl (VCM)-loaded antisolvent-induced in situ forming matrices. The series of fatty acid-based in situ forming matrices showed a low viscosity (5.47–13.97 cPs) and pH value in the range of 5.16–6.78, with high injectability through a 27-G needle (1.55–3.12 N). The preparations exhibited low tolerance to high concentrations of KH2PO4 solution (1.88–5.42% v/v) and depicted an electrical potential change during phase transformation. Their phase transition and matrix formation at the microscopic and macroscopic levels depended on the chain length of fatty acids and solvent characteristics. The VCM release pattern depended on the nucleation/crystallization and solvent exchange behaviors of the delivery system. The 35% w/v of C12–C16 fatty acid-based in situ forming matrix prolonged the VCM release over seven days in which C12, C14, C16 –based formulation reached 56, 84, and 85% cumulative drug release at 7th day. The release data fitted well with Higuchi’s model. The developed formulations presented efficient antimicrobial activities against standard S. aureus, MRSA, Escherichia coli, and Candida albicans. Hence, VCM-loaded antisolvent-induced fatty acid-based in situ forming matrix is a potential local delivery system for the treatment of local Gram-positive infection sites, such as joints, eyes, dermis of surgery sites, etc., in the future.

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Section: Resultsmentioning

confidence: 99%

Saturated Fatty Acid-Based In Situ Forming Matrices for Localized Antimicrobial Delivery

et al. 2020

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“…This rate of secondary self-formation was dependent on the ability of borneol crystallization in a given triacetin ratio at a given time. Theoretically, any unmixable object has an energy at its boundaries that enables nucleation and subsequently crystallization through a thermodynamic driving force [ 44 ]. The thermodynamic stability of a system can be disrupted by a variety of factors, including the introduction of new interfacial energy from sources such as the initial crystal, aqueous surface, and bubble surface, as well as supersaturation resulting from solvent reduction.…”

Section: Resultsmentioning

confidence: 99%

“…Regarding the first mechanism, solvent exchange, the solvent either underwent complete diffusion out of the system or encountered significant hindrance in its diffusion, leading to a state of negligible diffusivity [ 46 ]. The second mechanism, crystal growth, terminated when the thermodynamics became stable [ 44 , 45 ]. These findings suggested that borneol-based ISMs had two mechanisms for self-formation.…”

Section: Resultsmentioning

confidence: 99%

Ways to Assess and Regulate the Performance of a Bi-Mechanism-Induced Borneol-Based In Situ Forming Matrix

Lertsuphotvanit,

Sirirak,

Tamdee

et al. 2023

Pharmaceutics

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As an alternative to the traditional polymeric-based system, it is now possible to use an in situ forming system that is based on small molecules. Borneol was used as matrix formation in this study. While triacetin was incorporated into the formulation for prolonging the drug release. The objective of this study is to understand the initial period of the solvent exchange mechanism at the molecular level, which would provide a basis for explaining the matrix formation and drug release phenomena. The evaluation of basic physical properties, matrix formation, in vitro drug release, and molecular dynamics (MD) simulation of borneol-based in situ forming matrixes (ISM) was conducted in this study. The proportion of triacetin was found to determine the increase in density and viscosity. The density value was found to be related to viscosity which could be used for the purpose of prediction. Slow self-assembly of ISM upon the addition of triacetin was associated with higher viscosity and lower surface tension. This phenomenon enabled the regulation of solvent exchange and led to sustaining the drug release. In MD simulation using AMBER Tools, the free movement of the drug and the rapid approach to equilibrium of both solvent and water molecule in a solvent exchange mechanism in borneol-free ISM was observed, supporting that sustained release would not occur. Water infiltration was slowed down and NMP movement was restricted by the addition of borneol and triacetin. In addition, the increased proportion of triacetin promoted the diminished down of all substances’ movement because of the viscosity. The diffusion constant of relevant molecules decreased with the addition of borneol and/or triacetin. Although the addition of triacetin tended to slow down the solvent exchange and molecular movement from computation modelling results, it may not guarantee to imply the best drug release control. The Low triacetin-incorporated (5%) borneol-based ISM showed the highest ability to sustain the drug release due to its self-assembly and has proper solvent exchange. MD simulation addressed the details of the mechanism at the beginning of the process. Therefore, both MD and classical methods contribute to a clearer understanding of solvent exchange from the molecular to macroscopic level and from the first nanosecond of the formulation contact with water to the 10-day of drug release. These would be beneficial for subsequent research and development efforts in small molecule-based in situ forming systems.

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“…Drug molecules are subsequently enclosed in the gel and are then progressively released over time [16][17][18]. In the early phase, the rate of solvent exchange usually occurs rapidly and gradually reduces over time as the reaction reaches equilibrium as a result of the thermodynamic theory [52,53]. A higher borneol content was found nearby the interface area and gradually decreased with increasing the distance from the interface [54].…”

Section: Microscopic Changes In Gel Formationmentioning

confidence: 99%

Phase Inversion-Based Doxycycline Hyclate-Incorporated Borneol In Situ Gel for Periodontitis Treatment

Lertsuphotvanit

Tuntarawongsa

Chantadee

et al. 2023

Gels

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Borneol has been successfully employed as a gelling agent for in situ forming gel (ISG). While 40% borneol can regulate drug release, there is interest in novel approaches to achieve extended drug release, particularly through the incorporation of hydrophobic substances. Herein, triacetin was selected as a hydrophobic additive solvent for doxycycline hyclate (Dox)-loaded 40% borneol-based ISGs in N-methyl-2-pyrrolidone (NMP) or dimethyl sulfoxide (DMSO), which were subsequently evaluated in terms of their physicochemical properties, gel formation morphology, water sensitivity, drug release, and antimicrobial activities. ISG density and viscosity gradually decreased with the triacetin proportion to a viscosity of <12 cPs and slightly influenced the surface tension (33.14–44.33 mN/m). The low expelled force values (1.59–2.39 N) indicated the convenience of injection. All of the prepared ISGs exhibited favorable wettability and plastic deformation. Higher gel firmness from ISG prepared using NMP as a solvent contributed to the ability of more efficient controlled drug release. High triacetin (25%)-loaded ISG retarded solvent diffusion and gel formation, but diminished gel firmness and water sensitivity. ISG containing 5% triacetin efficiently prolonged Dox release up to 10 days with Fickian diffusion and presented effective antimicrobial activities against periodontitis pathogens such as Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans. Therefore, the Dox-loaded 40% borneol-based ISG with 5% triacetin is a potential effective local ISG for periodontitis treatment.

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Basic Concepts of Theory of Phase Transformations

Cited by 7 publications

References 0 publications

Saturated Fatty Acid-Based In Situ Forming Matrices for Localized Antimicrobial Delivery

Saturated Fatty Acid-Based In Situ Forming Matrices for Localized Antimicrobial Delivery

Ways to Assess and Regulate the Performance of a Bi-Mechanism-Induced Borneol-Based In Situ Forming Matrix

Phase Inversion-Based Doxycycline Hyclate-Incorporated Borneol In Situ Gel for Periodontitis Treatment

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