An In Vitro Method for Measuring the Dissolution and Release of Suspended Solids from Coacervates on the Skin Surface
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| Language: | English |
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University of Cincinnati / OhioLINK
2017
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| Online Access: | http://rave.ohiolink.edu/etdc/view?acc_num=ucin1490353836623474 |
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ndltd-OhioLink-oai-etd.ohiolink.edu-ucin1490353836623474 |
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NDLTD |
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English |
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Pharmaceuticals in vitro release testing coacervate polymer-surfactant system release rate topical bioavailability sebum |
| spellingShingle |
Pharmaceuticals in vitro release testing coacervate polymer-surfactant system release rate topical bioavailability sebum Baalbaki, Nada H. An In Vitro Method for Measuring the Dissolution and Release of Suspended Solids from Coacervates on the Skin Surface |
| author |
Baalbaki, Nada H. |
| author_facet |
Baalbaki, Nada H. |
| author_sort |
Baalbaki, Nada H. |
| title |
An In Vitro Method for Measuring the Dissolution and Release of Suspended Solids from Coacervates on the Skin Surface |
| title_short |
An In Vitro Method for Measuring the Dissolution and Release of Suspended Solids from Coacervates on the Skin Surface |
| title_full |
An In Vitro Method for Measuring the Dissolution and Release of Suspended Solids from Coacervates on the Skin Surface |
| title_fullStr |
An In Vitro Method for Measuring the Dissolution and Release of Suspended Solids from Coacervates on the Skin Surface |
| title_full_unstemmed |
An In Vitro Method for Measuring the Dissolution and Release of Suspended Solids from Coacervates on the Skin Surface |
| title_sort |
in vitro method for measuring the dissolution and release of suspended solids from coacervates on the skin surface |
| publisher |
University of Cincinnati / OhioLINK |
| publishDate |
2017 |
| url |
http://rave.ohiolink.edu/etdc/view?acc_num=ucin1490353836623474 |
| work_keys_str_mv |
AT baalbakinadah aninvitromethodformeasuringthedissolutionandreleaseofsuspendedsolidsfromcoacervatesontheskinsurface AT baalbakinadah invitromethodformeasuringthedissolutionandreleaseofsuspendedsolidsfromcoacervatesontheskinsurface |
| _version_ |
1719452066865217536 |
| spelling |
ndltd-OhioLink-oai-etd.ohiolink.edu-ucin14903538366234742021-08-03T07:00:57Z An In Vitro Method for Measuring the Dissolution and Release of Suspended Solids from Coacervates on the Skin Surface Baalbaki, Nada H. Pharmaceuticals in vitro release testing coacervate polymer-surfactant system release rate topical bioavailability sebum Complex coacervates of cationic polymers and anionic surfactants, which are produced spontaneously during the use of rinse‐off formulations, represent an important delivery vehicle for topical agents to the skin surface and appendages. The immiscible coacervate phase forms upon dilution and entrains particulate bioactive agents, improving their delivery and persistence on the skin. The practical efficacy of agents within coacervates on the skin surface is dependent on their release rate as it relates to topical bioavailability. This study explores the relationship between coacervate morphology and the release rate of entrained actives by evaluating the release kinetics of a model compound from within variable coacervate compositions into a simulated skin surface lipid film.An artificial sebum‐loaded cell culture insert method was developed and used to determine the release kinetics of the model compound, kinetin, from semi‐solid coacervate formulations into sebum. Coacervate compositions were prepared with cationic hydroxyethyl cellulose dodecyl sulfate (cat-HECDS), sodium dodecyl sulfate (NaDS), and water. Tested compositions mimicked the hydration range and relative excess surfactant content expected from coacervates produced during consumer use of commercial rinse-off formulations. Initial release testing showed a direct correlation between the diffusion-controlled release rate of kinetin and the relative water content and wt% ratio of anionic surfactant to charge neutral cat-HECDS of the coacervate composition. These relationships suggested a connection between complex salt’s network structure and compound release rate. Using cationic hydroxyethyl celluose (cat‐HEC) polymers of variable molecular weight and degree of charge substitution to prepare the cat‐HECDS, the relationship between coacervate phase and structure and the model agent’s release rate emerged. A comparison of the surfactant ion mixing plane phase diagrams for cat‐HECDS made with a cat‐HEC polymer of medium‐ and high‐ degrees of charge substitution revealed that the phase boundaries for the micellar region were dictated by the molar ratio of anions to cations (sulfur:nitrogen, S:N). The S:N also controls the degree of inter-polymer binding in the polycation-surfactant anion network. Low shear viscosities of the coacervate compositions measured using a squeeze flow rheometric method were inversely correlated to relative water content and S:N and were directly correlated with the release rate for kinetin. Using the relative content of complex salt and water, S:N, viscosity and [(S:N)×(1−weight fraction water)^−1], a predictive equation of moderate strength for the release rate of kinetin from cellulosic coacervate compositions was generated. From what is known about the impact of these variables on coacervate morphology, we propose the lipophilic kinetin molecules favorably partition into hydrophobic surfactant aggregates within the polyion-surfactant anion network during the deposition process and will diffuse through the hydrophilic inter-polymer channels connecting them as it exits the matrix. The trends evaluated in this work show that kinetin escapes the polyion-surfactant anion network more quickly when the network is hydrated and has been unraveled. This method can be used to help optimize the release rate of bioactive agents within coacervate vehicles and sheds light on the utility of coacervate deposition by dilution as a delivery matrix for topical agents to the skin surface and appendages. 2017-06-16 English text University of Cincinnati / OhioLINK http://rave.ohiolink.edu/etdc/view?acc_num=ucin1490353836623474 http://rave.ohiolink.edu/etdc/view?acc_num=ucin1490353836623474 unrestricted This thesis or dissertation is protected by copyright: some rights reserved. It is licensed for use under a Creative Commons license. Specific terms and permissions are available from this document's record in the OhioLINK ETD Center. |