Alpha-Mangostin Phase Inversion Induced In Situ Forming Gel

2019 ◽  
Vol 819 ◽  
pp. 202-208
Author(s):  
Setthapong Senarat ◽  
Takorn Chantadee ◽  
Wichai Santimaleeworagun ◽  
Yaowaruk Phorom ◽  
Thawatchai Phaechamud
Keyword(s):  
Phase Inversion ◽  
Extended Release ◽  
Initial Time ◽  
Low Viscosity ◽  
Microbial Inhibition ◽  
Formation Behavior ◽  
Density Values ◽  
Methyl Pyrrolidone ◽  
Rapid Transformation

Alpha-mangostin (aMG) phase inversion induced in situ forming gel (ISG) was prepared by dissolving matrix formers including palmitic acid (P) and lauric acid (L) in dimethyl sulfoxide (DMSO) and N-methyl pyrrolidone (NMP). The pH and density values were in range of 4.42-6.22 and 0.9731-1.0943 g.cm-3, respectively. The prepared formulas have low viscosity and high injectability which were suitable for injection. The gel formation behavior was affected by type of fatty acid and solvent. P dissolved in DMSO showed a rapid transformation into matrix at initial time. The extended release of aMG was attained in P-based ISG. aMG phase inversion induced ISG improved microbial inhibition.

Phase Inversion-Induced Rosin In Situ Forming Matrix Using Various Organic Biocompatible Solvents for Periodontitis Treatment

2020 ◽  
Vol 856 ◽  
pp. 237-244
Author(s):  
Nutdanai Lertsuphotvanit ◽  
Jongjan Mahadlek ◽  
Sarun Tuntarawongsa ◽  
Thawatchai Phaechamud
Keyword(s):  
Drug Delivery ◽  
Surface Tension ◽  
Antimicrobial Agent ◽  
Dimethyl Sulfoxide ◽  
Drug Delivery System ◽  
Delivery System ◽  
Phase Inversion ◽  
Contact Angles ◽  
Formation Behavior

In situ forming matrix (ISM) is an injectable drug delivery system containing a drug-loaded polymeric solution. It was applied for local drug administration such as into a periodontal pocket for periodontitis treatment with an antimicrobial agent. ISM can transform with phase inversion into the solid-like matrix after contact an aqueous environment by solvent exchange mechanism. This study aims to develop ISM which various concentrations of rosin (R) as matrix former dissolved in organic biocompatible and biodegradable solvents such as N-methyl-2-pyrrolidone, dimethyl sulfoxide and 2-pyrrolidone. Physicochemical characterization and matrix formation behavior owing to phase inversion of R ISM were evaluated including pH, density, viscosity, contact angles, surface tension, expelling force through a syringe, matrix formation behavior and morphological change. The density of all R ISM exhibited in the range of 1.03-1.11 g/cm3 and contact angles (9.04-44.13°) indicated a good wetting property. Higher R concentration decreased pH of ISM owing to increased amount of abietic and pimaric acid from R while the viscosity, contact angles and force for expelling a syringe were increased. The viscosity of R ISM in dimethyl sulfoxide was less than that in 2-pyrrolidone; thus, ISM using dimethyl sulfoxide as a solvent exhibited good injectability. ISM comprising R concentration > 30%w/w promoted a faster matrix growth in which the amount of occurred R matrix was enhanced with time and the rate of matrix formation was lower with time. Doxycycline Hyclate (Dx)-loaded 40%w/w ISM in dimethyl sulfoxide (Dx-DR) had pH of 3.70, density of 1.1084 ± 0.0005 g/ml, viscosity of 35.72 ± 0.00 cPs, contact angles of 26.87 ± 2.40°, surface tension of 37.11 ± 0.11 mN/m and expelling force of 23.98 ± 0.18 N. It showed the sustainable Dx release in simulated crevicular fluid and the efficient antimicrobial activity against Staphylococcus aureus and Porphyromonas gingivalis. Thus, this phase inversion induced R ISM using dimethyl sulfoxide as a solvent showed potential as an antimicrobial agent-loaded drug delivery system for periodontitis treatment.

Characterization of Lauric Acid Precipitated from Biocompatible Solvents

2019 ◽  
Vol 819 ◽  
pp. 209-214
Author(s):  
Napaphol Puyathorn ◽  
Takorn Chantadee ◽  
Setthapong Senarat ◽  
Thawatchai Phaechamud
Keyword(s):  
Lauric Acid ◽  
Phase Inversion ◽  
Water Resistance ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Degradation Temperature ◽  
Lower Melting Point ◽  
Methyl Pyrrolidone

Water resistance of lauric acid (L) dissolved in biocompatible solvents mainly depended on the water affinity of solvent. L in DMSO (DL) was most sensitive to water and higher than L in N-methyl pyrrolidone (NL) and L in 2-pyrolidone (PL), respectively. From scanning electron microscope, differential scanning calorimetry, thermogravimetric analysis, powder x-ray diffractometry and hot stage microscope tests revealed the alteration of L crystal owing to the interference by solvent during precipitation. All L precipitates had lower melting point and degradation temperature than intact L in which L precipitated from 2-pyrrolidone exhibited the lowest melting temperature. These characteristics will be useful for modifying L in phase inversion in situ forming gel.

Gamboge Resin-Based Phase Separation In Situ Forming Gel

2019 ◽  
Vol 819 ◽  
pp. 215-220
Author(s):  
Ei Mon Khaing ◽  
Takorn Chantadee ◽  
Torsak Intaraphairot ◽  
Thawatchai Phaechamud
Keyword(s):  
Drug Delivery ◽  
Drug Delivery System ◽  
Delivery System ◽  
Antimicrobial Activities ◽  
Solid Matrix ◽  
Gambogic Acid ◽  
Low Viscosity ◽  
Controlled Drug Delivery System ◽  
Methyl Pyrrolidone

Abstract. The in situ forming gel (ISG) has been developed as a controlled drug delivery system to prolong drug release. This study aims to prepare ISG system based on gamboge resin (GB) as matrix former. The various amounts of GB dissolving in dimethyl sulfoxide (DMSO) and N-methyl pyrrolidone (NMP) were used to obtain the ISG systems and evaluated for their pH, viscosity, injectability and matrix forming. The antimicrobial activities against three strains of Staphylococcus aureus including the Methicilin Resistant S. aureus (MRSA) and Porphyromonas gingivalis were conducted. GB ISG systems exhibited good injectability with low viscosity. GB in DMSO showed a faster transformation to solid matrix compared to that in NMP. The gambogic acid (GA) content in crude GB was 33.70 ± 0.13%. The sustainable GA release from GB ISG could be attained. Thus, GB ISG exhibits the potential application as a drug delivery system for active compounds and is enable for using as a therapeutic dosage form owing to its antimicrobial activity.

Localized Corrosion of Binary Mg-Nd Alloys in Chloride-Containing Electrolyte Using a Scanning Vibrating Electrode Technique

CORROSION ◽  
2012 ◽  
Vol 68 (6) ◽  
pp. 489-498 ◽  
Author(s):  
G. Williams ◽  
K. Gusieva ◽  
N. Birbilis
Keyword(s):  
Localized Corrosion ◽  
Radial Expansion ◽  
Alloying Additions ◽  
Corrosion Rates ◽  
Surface Breakdown ◽  
Density Values ◽  
Intact Surface ◽  
Mean Current ◽  
Electrode Technique

The influence of neodymium (Nd) alloying additions in the 0.47 wt% to 3.53 wt% range on the localized corrosion behavior of Mg, when freely corroding in aqueous sodium chloride (NaCl) electrolyte, is investigated using an in situ scanning vibrating electrode technique (SVET). For all samples, the point of surface breakdown is an intense focal anode that expands radially with respect to time, revealing a cathodically activated interior, which is galvanically coupled with the local anode at the perimeter. However, for Nd compositions of ≤0.74%, radial expansion ceases within ca. 2 h of initiation, whereupon dark filiform-like corrosion features are observed, which traverse over the exposed Mg surface. For Nd additions of ≥1.25%, the radial expansion continues with time up to a point where the entire intact surface becomes consumed. The intensity of the local anode ring of circular corroded regions is seen to increase as more cathodically activated corroded surface becomes exposed. Mean current density values measured within these corroded areas increase progressively with Nd content, leading to a progressive rise in localized corrosion rates. The cathodic activation of corroded regions is proposed to derive from an enrichment of noble, Nd-rich intermetallic grains caused as the alpha-Mg phase becomes attacked at local anode sites.

scholarly journals In situ forming phase-inversion implants for sustained ocular delivery of triamcinolone acetonide

2018 ◽  
Vol 9 (2) ◽  
pp. 534-542 ◽  
Author(s):  
Ravi Sheshala ◽  
Gan Chew Hong ◽  
Wong Pui Yee ◽  
Venkata Srikanth Meka ◽  
Raghu Raj Singh Thakur
Keyword(s):  
Triamcinolone Acetonide ◽  
Phase Inversion ◽  
Ocular Delivery ◽  
In Situ Forming
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