Photophysics of 7-(diethylamino)coumarin-3-carboxylic acid in cationic micelles: effect of chain length and head group of the surfactants and urea

RSC Advances ◽  
2014 ◽  
Vol 4 (64) ◽  
pp. 34026-34036 ◽  
Author(s):  
Aninda Chatterjee ◽  
Banibrata Maity ◽  
Debabrata Seth
Keyword(s):  
Carboxylic Acid ◽  
Chain Length ◽  
Head Group ◽  
Cationic Micelles

Mechanisms of Drug Solubilization by Polar Lipids in Biorelevant Media

2020 ◽  
Author(s):  
Vladimir Katev ◽  
Zahari Vinarov ◽  
Slavka S. Tcholakova
Keyword(s):  
Chain Length ◽  
Acyl Chain ◽  
Polar Lipids ◽  
Superior Performance ◽  
Head Group ◽  
Formulation Development ◽  
Biorelevant Media ◽  
Drug Solubilization ◽  
Colloidal Aggregates ◽  
Class 1

Despite the widespread use of lipid excipients in both academic research and oral formulation development, rational selection guidelines are still missing. In the current study, we aimed to establish a link between the molecular structure of commonly used polar lipids and drug solubilization in biorelevant media. We studied the effect of 26 polar lipids of the fatty acid, phospholipid or monoglyceride type on the solubilization of fenofibrate in a two-stage <i>in vitro</i> GI tract model. The main trends were checked also with progesterone and danazol.<br>Based on their fenofibrate solubilization efficiency, the polar lipids can be grouped in 3 main classes. Class 1 substances (n = 5) provide biggest enhancement of drug solubilization (>10-fold) and are composed only by unsaturated compounds. Class 2 materials (n = 10) have an intermediate effect (3-10 fold increase) and are composed primarily (80 %) of saturated compounds. Class 3 materials (n = 11) have very low or no effect on drug solubilization and are entirely composed of saturated compounds.<br>The observed behaviour of the polar lipids was rationalized by using two classical physicochemical parameters: the acyl chain phase transition temperature (<i>T</i><sub>m</sub>) and the critical micellar concentration (CMC). Hence, the superior performance of class 1 polar lipids was explained by the double bonds in their acyl chains, which: (1) significantly decrease <i>T</i><sub>m</sub>, allowing these C18 lipids to form colloidal aggregates and (2) prevent tight packing of the molecules in the aggregates, resulting in bigger volume available for drug solubilization. Long-chain (C18) saturated polar lipids had no significant effect on drug solubilization because their <i>T</i><sub>m</sub> was much higher than the temperature of the experiment (<i>T</i> = 37 C) and, therefore, their association in colloidal aggregates was limited. On the other end of the spectrum, the short chain octanoic acid manifested a high CMC (50 mM), which had to be exceeded in order to enhance drug solubilization. When these two parameters were satisfied (C > CMC, <i>T</i><sub>m</sub> < <i>T</i><sub>exp</sub>), the increase of the polar lipid chain length increased the drug solubilization capacity (similarly to classical surfactants), due to the decreased CMC and bigger volume available for solubilization.<br>The hydrophilic head group also has a dramatic impact on the drug solubilization enhancement, with polar lipids performance decreasing in the order: choline phospholipids > monoglycerides > fatty acids.<br>As both the acyl chain length and the head group type are structural features of the polar lipids, and not of the solubilized drugs, the impact of <i>T</i><sub>m</sub> and CMC on solubilization by polar lipids should hold true for a wide variety of hydrophobic molecules. The obtained mechanistic insights can guide rational drug formulation development and thus support modern drug discovery pipelines.<br>

Mechanisms of Drug Solubilization by Polar Lipids in Biorelevant Media

2020 ◽  
Author(s):  
Vladimir Katev ◽  
Zahari Vinarov ◽  
Slavka S. Tcholakova
Keyword(s):  
Chain Length ◽  
Acyl Chain ◽  
Polar Lipids ◽  
Superior Performance ◽  
Head Group ◽  
Formulation Development ◽  
Biorelevant Media ◽  
Drug Solubilization ◽  
Colloidal Aggregates ◽  
Class 1

Despite the widespread use of lipid excipients in both academic research and oral formulation development, rational selection guidelines are still missing. In the current study, we aimed to establish a link between the molecular structure of commonly used polar lipids and drug solubilization in biorelevant media. We studied the effect of 26 polar lipids of the fatty acid, phospholipid or monoglyceride type on the solubilization of fenofibrate in a two-stage <i>in vitro</i> GI tract model. The main trends were checked also with progesterone and danazol.<br>Based on their fenofibrate solubilization efficiency, the polar lipids can be grouped in 3 main classes. Class 1 substances (n = 5) provide biggest enhancement of drug solubilization (>10-fold) and are composed only by unsaturated compounds. Class 2 materials (n = 10) have an intermediate effect (3-10 fold increase) and are composed primarily (80 %) of saturated compounds. Class 3 materials (n = 11) have very low or no effect on drug solubilization and are entirely composed of saturated compounds.<br>The observed behaviour of the polar lipids was rationalized by using two classical physicochemical parameters: the acyl chain phase transition temperature (<i>T</i><sub>m</sub>) and the critical micellar concentration (CMC). Hence, the superior performance of class 1 polar lipids was explained by the double bonds in their acyl chains, which: (1) significantly decrease <i>T</i><sub>m</sub>, allowing these C18 lipids to form colloidal aggregates and (2) prevent tight packing of the molecules in the aggregates, resulting in bigger volume available for drug solubilization. Long-chain (C18) saturated polar lipids had no significant effect on drug solubilization because their <i>T</i><sub>m</sub> was much higher than the temperature of the experiment (<i>T</i> = 37 C) and, therefore, their association in colloidal aggregates was limited. On the other end of the spectrum, the short chain octanoic acid manifested a high CMC (50 mM), which had to be exceeded in order to enhance drug solubilization. When these two parameters were satisfied (C > CMC, <i>T</i><sub>m</sub> < <i>T</i><sub>exp</sub>), the increase of the polar lipid chain length increased the drug solubilization capacity (similarly to classical surfactants), due to the decreased CMC and bigger volume available for solubilization.<br>The hydrophilic head group also has a dramatic impact on the drug solubilization enhancement, with polar lipids performance decreasing in the order: choline phospholipids > monoglycerides > fatty acids.<br>As both the acyl chain length and the head group type are structural features of the polar lipids, and not of the solubilized drugs, the impact of <i>T</i><sub>m</sub> and CMC on solubilization by polar lipids should hold true for a wide variety of hydrophobic molecules. The obtained mechanistic insights can guide rational drug formulation development and thus support modern drug discovery pipelines.<br>

scholarly journals Responsive Polyesters with Alkene and Carboxylic Acid Side-Groups for Tissue Engineering Applications

Polymers ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1636
Author(s):  
Stella Afroditi Mountaki ◽  
Maria Kaliva ◽  
Konstantinos Loukelis ◽  
Maria Chatzinikolaidou ◽  
Maria Vamvakaki
Keyword(s):  
Carboxylic Acid ◽  
Chain Length ◽  
Main Chain ◽  
Alkyl Chain ◽  
Click Reaction ◽  
Irradiation Time ◽  
Alkyl Chain Length ◽  
Polymer Chains ◽  
Condensation Polymerization ◽  
L929 Fibroblast

Main chain polyesters have been extensively used in the biomedical field. Despite their many advantages, including biocompatibility, biodegradability, and others, these materials are rather inert and lack specific functionalities which will endow them with additional biological and responsive properties. In this work, novel pH-responsive main chain polyesters have been prepared by a conventional condensation polymerization of a vinyl functionalized diol with a diacid chloride, followed by a photo-induced thiol-ene click reaction to attach functional carboxylic acid side-groups along the polymer chains. Two different mercaptocarboxylic acids were employed, allowing to vary the alkyl chain length of the polymer pendant groups. Moreover, the degree of modification, and as a result, the carboxylic acid content of the polymers, was easily tuned by varying the irradiation time during the click reaction. Both these parameters, were shown to strongly influence the responsive behavior of the polyesters, which presented adjustable pKα values and water solubilities. Finally, the difunctional polyesters bearing the alkene and carboxylic acid functionalities enabled the preparation of cross-linked polyester films by chemically linking the pendant vinyl bonds on the polymer side groups. The biocompatibility of the cross-linked polymers films was assessed in L929 fibroblast cultures and showed that the cell viability, proliferation, and attachment were greatly promoted on the polyester surface, bearing the shorter alkyl chain length side groups and the higher fraction of carboxylic acid functionalities.

Effect of Surfactant Chain Length on the Binding Interaction of a Biological Photosensitizer with Cationic Micelles

2008 ◽  
Vol 112 (12) ◽  
pp. 3684-3692 ◽  
Author(s):  
Alok Chakrabarty ◽  
Paramita Das ◽  
Arabinda Mallick ◽  
Nitin Chattopadhyay
Keyword(s):  
Chain Length ◽  
Binding Interaction ◽  
Cationic Micelles

A Quantitative Analysis of the Effects of Head Group Bulk on SN2 and E2 Reactions in Cationic Micelles

Langmuir ◽  
1997 ◽  
Vol 13 (17) ◽  
pp. 4583-4587 ◽  
Author(s):  
Lucia Brinchi ◽  
Pietro Di Profio ◽  
Raimondo Germani ◽  
Gianfranco Savelli ◽  
Clifford A. Bunton
Keyword(s):  
Quantitative Analysis ◽  
Head Group ◽  
Cationic Micelles

scholarly journals Nighttime oxidation of surfactants at the air–water interface: effects of chain length, head group and saturation

2018 ◽  
Vol 18 (5) ◽  
pp. 3249-3268 ◽  
Author(s):  
Federica Sebastiani ◽  
Richard A. Campbell ◽  
Kunal Rastogi ◽  
Christian Pfrang
Keyword(s):  
Oleic Acid ◽  
Double Bond ◽  
Methyl Ester ◽  
Reaction Kinetics ◽  
Chain Length ◽  
Rate Coefficients ◽  
Head Group ◽  
Water Interface ◽  
Organic Monolayers ◽  
Air Water Interface

Abstract. Reactions of the key atmospheric nighttime oxidant NO3 with organic monolayers at the air–water interface are used as proxies for the ageing of organic-coated aqueous aerosols. The surfactant molecules chosen for this study are oleic acid (OA), palmitoleic acid (POA), methyl oleate (MO) and stearic acid (SA) to investigate the effects of chain length, head group and degree of unsaturation on the reaction kinetics and products formed. Fully and partially deuterated surfactants were studied using neutron reflectometry (NR) to determine the reaction kinetics of organic monolayers with NO3 at the air–water interface for the first time. Kinetic modelling allowed us to determine the rate coefficients for the oxidation of OA, POA and MO monolayers to be (2.8±0.7) × 10−8, (2.4±0.5) × 10−8and (3.3±0.6) × 10−8 cm2 molecule−1 s−1 for fitted initial desorption lifetimes of NO3 at the closely packed organic monolayers, τd, NO3, 1, of 8.1±4.0, 16±4.0 and 8.1±3.0 ns, respectively. The approximately doubled desorption lifetime found in the best fit for POA compared to OA and MO is consistent with a more accessible double bond associated with the shorter alkyl chain of POA facilitating initial NO3 attack at the double bond in a closely packed monolayer. The corresponding uptake coefficients for OA, POA and MO were found to be (2.1±0.5) × 10−3, (1.7±0.3) × 10−3 and (2.1±0.4) × 10−3, respectively. For the much slower NO3-initiated oxidation of the saturated surfactant SA we estimated a loss rate of approximately (5±1) × 10−12 cm2 molecule−1 s−1, which we consider to be an upper limit for the reactive loss, and estimated an uptake coefficient of ca. (5±1) × 10−7. Our investigations demonstrate that NO3 will contribute substantially to the processing of unsaturated surfactants at the air–water interface during nighttime given its reactivity is ca. 2 orders of magnitude higher than that of O3. Furthermore, the relative contributions of NO3 and O3 to the oxidative losses vary massively between species that are closely related in structure: NO3 reacts ca. 400 times faster than O3 with the common model surfactant oleic acid, but only ca. 60 times faster with its methyl ester MO. It is therefore necessary to perform a case-by-case assessment of the relative contributions of the different degradation routes for any specific surfactant. The overall impact of NO3 on the fate of saturated surfactants is slightly less clear given the lack of prior kinetic data for comparison, but NO3 is likely to contribute significantly to the loss of saturated species and dominate their loss during nighttime. The retention of the organic character at the air–water interface differs fundamentally between the different surfactant species: the fatty acids studied (OA and POA) form products with a yield of  ∼ 20 % that are stable at the interface while NO3-initiated oxidation of the methyl ester MO rapidly and effectively removes the organic character ( ≤ 3 % surface-active products). The film-forming potential of reaction products in real aerosol is thus likely to depend on the relative proportions of saturated and unsaturated surfactants as well as the head group properties. Atmospheric lifetimes of unsaturated species are much longer than those determined with respect to their reactions at the air–water interface, so they must be protected from oxidative attack, for example, by incorporation into a complex aerosol matrix or in mixed surface films with yet unexplored kinetic behaviour.

scholarly journals Effects of adrenaline on ketogenesis from long- and medium-chain fatty acids in starved rats

1982 ◽  
Vol 204 (3) ◽  
pp. 749-756 ◽  
Author(s):  
M C Sugden ◽  
D I Watts ◽  
C E Marshall
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Blood Glucose ◽  
Carboxylic Acid ◽  
Chain Length ◽  
Clinical Significance ◽  
Ketone Body ◽  
Medium Chain ◽  
Medium Chain Fatty Acids ◽  
Increase Blood Glucose

1. Injection of adrenaline into 24 h-starved rats caused a 69% decrease in blood [ketone-body] (3-hydroxybutyrate plus acetoacetate), accompanied by a decreased [3-hydroxybutyrate]/[acetoacetate] ratio. Blood [glucose] and [lactate] increased, but [alanine] was unchanged. 2. Adrenaline also decreased [ketone-body] after intragastric feeding of both long- and medium-chain triacylglycerol. The latter decrease was observed after suppression of lipolysis with 5-methylpyrazole-3-carboxylic acid, indicating that the antiketogenic action of adrenaline was not dependent on the chain length of the precursor fatty acid. 3. The actions of adrenaline to decrease blood [ketone-body] and to increase blood [glucose] were not observed after administration of 3-mercaptopicolinate, an inhibitor of gluconeogenesis. This suggests that these effects of the hormone are related. 4. The possible clinical significance of the results is discussed with reference to the restricted ketosis often observed after surgical or orthopaedic injury.

Glycosylinositol phosphoceramide-specific phospholipase D activity catalyzes transphosphatidylation

2019 ◽  
Vol 166 (5) ◽  
pp. 441-448 ◽  
Author(s):  
Rumana Yesmin Hasi ◽  
Makoto Miyagi ◽  
Katsuya Morito ◽  
Toshiki Ishikawa ◽  
Maki Kawai-Yamada ◽  
...  
Keyword(s):  
Chain Length ◽  
Phospholipase D ◽  
Secondary Alcohol ◽  
Primary Alcohol ◽  
Tertiary Alcohol ◽  
Head Group ◽  
Polar Head Group ◽  
Polar Head ◽  
A Chain ◽  
Sugar Chains

Abstract Glycosylinositol phosphoceramide (GIPC) is the most abundant sphingolipid in plants and fungi. Recently, we detected GIPC-specific phospholipase D (GIPC-PLD) activity in plants. Here, we found that GIPC-PLD activity in young cabbage leaves catalyzes transphosphatidylation. The available alcohol for this reaction is a primary alcohol with a chain length below C4. Neither secondary alcohol, tertiary alcohol, choline, serine nor glycerol serves as an acceptor for transphosphatidylation of GIPC-PLD. We also found that cabbage GIPC-PLD prefers GIPC containing two sugars. Neither inositol phosphoceramide, mannosylinositol phosphoceramide nor GIPC with three sugar chains served as substrate. GIPC-PLD will become a useful catalyst for modification of polar head group of sphingophospholipid.

Effects of tail alkyl chain length (n), head group structure and junction (Z) on amphiphilic properties of 1-Z-R-d,l-xylitol compounds (R=CnH2n+1)

1999 ◽  
Vol 182 (2) ◽  
pp. 221-236 ◽  
Author(s):  
M.P. Savelli ◽  
P. Van Roekeghem ◽  
O. Douillet ◽  
G. Cavé ◽  
P. Godé ◽  
...  
Keyword(s):  
Chain Length ◽  
Alkyl Chain ◽  
Group Structure ◽  
Alkyl Chain Length ◽  
Head Group

Effect of the Phospholipid Chain Length and Head Group on Beta-Phase Formation of Poly(9,9-dioctylfluorene) Enclosed in Liposomes

2013 ◽  
Vol 89 (6) ◽  
pp. 1471-1478 ◽  
Author(s):  
María J. Tapia ◽  
María Monteserín ◽  
Hugh D. Burrows ◽  
João S. Seixas de Melo ◽  
Joan Estelrich
Keyword(s):  
Chain Length ◽  
Phase Formation ◽  
Beta Phase ◽  
Head Group
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