Qualitative and quantitative characterization of the in vitro dehydration process of hydrogel contact lenses

Detalhes bibliográficos
Autor(a) principal: González-Méijome, José Manuel
Data de Publicação: 2007
Outros Autores: López-Alemany, António, Parafita, Manuel A., Almeida, José B., Refojo, Miguel F.
Tipo de documento: Artigo
Idioma: eng
Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
Texto Completo: https://hdl.handle.net/1822/8416
Resumo: PURPOSE: To investigate the in vitro dehydration process of conventional hydrogel and silicone-hydrogel contact lens materials. METHODS: Eight conventional hydrogel and five silicone-hydrogel contact lenses were dehydrated under controlled environmental conditions on an analytical balance. Data were taken at 1-min intervals and dehydration curves of cumulative dehydration (CD), valid dehydration (VD), and dehydration rate (DR) were obtained. Several quantitative descriptors of the dehydration process were obtained by further processing of the information. RESULTS: Duration of phase I (r(2) = 0.921), CD at end of phase I (r(2) = 0.971), time to achieve a DR of -1%/min (r(2) = 0.946) were strongly correlated with equilibrium water content (EWC) of the materials. For each individual sample, the VD at different time intervals can be accurately determined using a 2nd order regression equation (r(2) > 0.99 for all samples). The first 5 min of the dehydration process show a relatively uniform average CD of about -1.5%/min. After that, there was a trend towards higher average CD for the following 15 min as the EWC of the material increases (r(2) = 0.701). As a consequence, average VD for the first 5 min displayed a negative correlation with EWC (r(2) = 0.835), and a trend towards uniformization among CL materials for the following periods (r(2) = 0.014). Overall, silicone-hydrogel materials display a lower dehydration, but this seems to be primarily due to their lower EWC. CONCLUSIONS: DR curves under the conditions of the present study can be described as a three-phase process. Phase I consists of a relatively uniform DR with a duration that ranges from 10 to almost 60 min and is strongly correlated with the EWC of the polymer as it is the CD during this phase. Overall, HEMA-based hydrogels dehydrate to a greater extent and faster than silicone-hydrogel materials. There are differences in water retention between lenses of similar water content and thickness that should be further investigated.
id RCAP_6c1ee909bf0cedf6a4adfe517a13908b
oai_identifier_str oai:repositorium.sdum.uminho.pt:1822/8416
network_acronym_str RCAP
network_name_str Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
repository_id_str 7160
spelling Qualitative and quantitative characterization of the in vitro dehydration process of hydrogel contact lensesHydrogel dehydrationPolymerContact lensGravimetric methodgravimetryhydrationhydrogelsilicone-hydrogelcontact lensesdehydrationScience & TechnologyPURPOSE: To investigate the in vitro dehydration process of conventional hydrogel and silicone-hydrogel contact lens materials. METHODS: Eight conventional hydrogel and five silicone-hydrogel contact lenses were dehydrated under controlled environmental conditions on an analytical balance. Data were taken at 1-min intervals and dehydration curves of cumulative dehydration (CD), valid dehydration (VD), and dehydration rate (DR) were obtained. Several quantitative descriptors of the dehydration process were obtained by further processing of the information. RESULTS: Duration of phase I (r(2) = 0.921), CD at end of phase I (r(2) = 0.971), time to achieve a DR of -1%/min (r(2) = 0.946) were strongly correlated with equilibrium water content (EWC) of the materials. For each individual sample, the VD at different time intervals can be accurately determined using a 2nd order regression equation (r(2) > 0.99 for all samples). The first 5 min of the dehydration process show a relatively uniform average CD of about -1.5%/min. After that, there was a trend towards higher average CD for the following 15 min as the EWC of the material increases (r(2) = 0.701). As a consequence, average VD for the first 5 min displayed a negative correlation with EWC (r(2) = 0.835), and a trend towards uniformization among CL materials for the following periods (r(2) = 0.014). Overall, silicone-hydrogel materials display a lower dehydration, but this seems to be primarily due to their lower EWC. CONCLUSIONS: DR curves under the conditions of the present study can be described as a three-phase process. Phase I consists of a relatively uniform DR with a duration that ranges from 10 to almost 60 min and is strongly correlated with the EWC of the polymer as it is the CD during this phase. Overall, HEMA-based hydrogels dehydrate to a greater extent and faster than silicone-hydrogel materials. There are differences in water retention between lenses of similar water content and thickness that should be further investigated.WileyUniversidade do MinhoGonzález-Méijome, José ManuelLópez-Alemany, AntónioParafita, Manuel A.Almeida, José B.Refojo, Miguel F.2007-022007-02-01T00:00:00Zinfo:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/articleapplication/pdfhttps://hdl.handle.net/1822/8416eng"Journal of Biomedical Material Research B - Applied Biomaterials". ISSN 1552-4973. 83:2 (Feb. 2007) 512-526.1552-497310.1002/jbm.b.3082417471515info:eu-repo/semantics/openAccessreponame:Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)instname:Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informaçãoinstacron:RCAAP2023-07-21T12:23:13Zoai:repositorium.sdum.uminho.pt:1822/8416Portal AgregadorONGhttps://www.rcaap.pt/oai/openaireopendoar:71602024-03-19T19:16:54.341689Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) - Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informaçãofalse
dc.title.none.fl_str_mv Qualitative and quantitative characterization of the in vitro dehydration process of hydrogel contact lenses
title Qualitative and quantitative characterization of the in vitro dehydration process of hydrogel contact lenses
spellingShingle Qualitative and quantitative characterization of the in vitro dehydration process of hydrogel contact lenses
González-Méijome, José Manuel
Hydrogel dehydration
Polymer
Contact lens
Gravimetric method
gravimetry
hydration
hydrogel
silicone-hydrogel
contact lenses
dehydration
Science & Technology
title_short Qualitative and quantitative characterization of the in vitro dehydration process of hydrogel contact lenses
title_full Qualitative and quantitative characterization of the in vitro dehydration process of hydrogel contact lenses
title_fullStr Qualitative and quantitative characterization of the in vitro dehydration process of hydrogel contact lenses
title_full_unstemmed Qualitative and quantitative characterization of the in vitro dehydration process of hydrogel contact lenses
title_sort Qualitative and quantitative characterization of the in vitro dehydration process of hydrogel contact lenses
author González-Méijome, José Manuel
author_facet González-Méijome, José Manuel
López-Alemany, António
Parafita, Manuel A.
Almeida, José B.
Refojo, Miguel F.
author_role author
author2 López-Alemany, António
Parafita, Manuel A.
Almeida, José B.
Refojo, Miguel F.
author2_role author
author
author
author
dc.contributor.none.fl_str_mv Universidade do Minho
dc.contributor.author.fl_str_mv González-Méijome, José Manuel
López-Alemany, António
Parafita, Manuel A.
Almeida, José B.
Refojo, Miguel F.
dc.subject.por.fl_str_mv Hydrogel dehydration
Polymer
Contact lens
Gravimetric method
gravimetry
hydration
hydrogel
silicone-hydrogel
contact lenses
dehydration
Science & Technology
topic Hydrogel dehydration
Polymer
Contact lens
Gravimetric method
gravimetry
hydration
hydrogel
silicone-hydrogel
contact lenses
dehydration
Science & Technology
description PURPOSE: To investigate the in vitro dehydration process of conventional hydrogel and silicone-hydrogel contact lens materials. METHODS: Eight conventional hydrogel and five silicone-hydrogel contact lenses were dehydrated under controlled environmental conditions on an analytical balance. Data were taken at 1-min intervals and dehydration curves of cumulative dehydration (CD), valid dehydration (VD), and dehydration rate (DR) were obtained. Several quantitative descriptors of the dehydration process were obtained by further processing of the information. RESULTS: Duration of phase I (r(2) = 0.921), CD at end of phase I (r(2) = 0.971), time to achieve a DR of -1%/min (r(2) = 0.946) were strongly correlated with equilibrium water content (EWC) of the materials. For each individual sample, the VD at different time intervals can be accurately determined using a 2nd order regression equation (r(2) > 0.99 for all samples). The first 5 min of the dehydration process show a relatively uniform average CD of about -1.5%/min. After that, there was a trend towards higher average CD for the following 15 min as the EWC of the material increases (r(2) = 0.701). As a consequence, average VD for the first 5 min displayed a negative correlation with EWC (r(2) = 0.835), and a trend towards uniformization among CL materials for the following periods (r(2) = 0.014). Overall, silicone-hydrogel materials display a lower dehydration, but this seems to be primarily due to their lower EWC. CONCLUSIONS: DR curves under the conditions of the present study can be described as a three-phase process. Phase I consists of a relatively uniform DR with a duration that ranges from 10 to almost 60 min and is strongly correlated with the EWC of the polymer as it is the CD during this phase. Overall, HEMA-based hydrogels dehydrate to a greater extent and faster than silicone-hydrogel materials. There are differences in water retention between lenses of similar water content and thickness that should be further investigated.
publishDate 2007
dc.date.none.fl_str_mv 2007-02
2007-02-01T00:00:00Z
dc.type.status.fl_str_mv info:eu-repo/semantics/publishedVersion
dc.type.driver.fl_str_mv info:eu-repo/semantics/article
format article
status_str publishedVersion
dc.identifier.uri.fl_str_mv https://hdl.handle.net/1822/8416
url https://hdl.handle.net/1822/8416
dc.language.iso.fl_str_mv eng
language eng
dc.relation.none.fl_str_mv "Journal of Biomedical Material Research B - Applied Biomaterials". ISSN 1552-4973. 83:2 (Feb. 2007) 512-526.
1552-4973
10.1002/jbm.b.30824
17471515
dc.rights.driver.fl_str_mv info:eu-repo/semantics/openAccess
eu_rights_str_mv openAccess
dc.format.none.fl_str_mv application/pdf
dc.publisher.none.fl_str_mv Wiley
publisher.none.fl_str_mv Wiley
dc.source.none.fl_str_mv reponame:Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
instname:Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informação
instacron:RCAAP
instname_str Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informação
instacron_str RCAAP
institution RCAAP
reponame_str Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
collection Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
repository.name.fl_str_mv Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) - Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informação
repository.mail.fl_str_mv
_version_ 1799132619292540928