Controlled Release of Biomolecules from pH-sensitive Network Polymers Prepared by Radiation Polymerization

Mahkam, Mehrdad; Allahverdipoor, M.

doi:10.1080/10611860410001688009

Cited by 22 publications

(13 citation statements)

References 13 publications

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“…1, 4-Bis (methacryloyloxyethyl) terephthalate (CA), and 5-[4-(hydroxyl phenyl)azo] salicylic acid (HPAS) were prepared by the methods described in the literatures (Mahkam et al, 2004;Mahkam and Allahverdipoor, 2004), respectively.…”

Section: Materials and Measurementsmentioning

confidence: 99%

Synthesis and characterization of acrylic type hydrogels containing azo derivatives of 5-amino salicylic acid for colon-specific drug delivery

2006

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pH-sensitive hydrogels are suitable candidates for oral delivery of therapeutic peptides, proteins and drugs, due to their ability to respond to environmental pH changes. Terephthalic acid was covalently linked with 2-hydroxyethyl methacrylate (HEMA), abbreviated as cross-linking agent (CA). Acryloyl ester of 5-[4-(hydroxy phenyl) azo] salicylic acid (HPAS) as an azo derivative of 5-amino salicylic acid (5-ASA) was prepared under mild conditions. The HPAS was covalently linked with acryloyl chloride, abbreviated as APAS. Free radical cross-linking copolymerization of polymerizable azo derivative of 5-ASA (APAS) and methacrylic acid (MAA) in two different molar ratios, with the various ratios CA as cross-linking agent were carried out with using 2, 2'-azobisisobutyronitrile (AIBN) as initiator at the temperature range 60-70 degrees C. The composition of the cross-linked three-dimensional polymers was determined by FTIR spectroscopy. Glass transition temperature (Tg) of the network polymers was determined calorimetrically. The hydrolysis of drug-polymer conjugates was carried out in cellophane membrane dialysis bags containing aqueous buffer solutions (pH 7.4 and pH 1) at 37 degrees C. The effect of copolymer composition on the hydrolytic degradation was studied in simulated gastric fluid (SGF, pH 1) and simulated intestinal fluid (SIF, pH 7.4) at 37 degrees C. Monitoring of the hydrolysis process by HPLC and UV spectroscopy shows that the azo prodrug (HPAS) was released by hydrolysis of the ester bond located between the HPAS and the polymer chain. The drug-release profiles indicate that amount drug release dependent on the content of MAA groups and crosslinking.

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Section: Materials and Measurementsmentioning

confidence: 99%

Synthesis and characterization of acrylic type hydrogels containing azo derivatives of 5-amino salicylic acid for colon-specific drug delivery

2006

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“…Mahkam ve arkadaşları 2004 yılında gerçekleştirdikleri çalışmada radyasyon polimerizasyonuyla Hidroksietilmetakrilat (HEMA) ve Memetilmetakrilat (MAA) bazlı kopolimerler hazırmışlar ve hidrojellerin pH 1-7.4'deki şişme davranışlarının farklı olduğunu gözlemlemişlerdir [6]. Bütün bu özelliklerinden dolayı, hidrojellerin şişme kontrollü salım sistemlerinde taşıyıcı olarak kullanımları yıllardır araştırılmaktadır.…”

Section: Introductionunclassified

Photocrosslinked Poly(Ethylen Glycol) Hydrogels for Controlled Drug Delivery

Ayhan¹

2014

Turk J Bioch

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Objective: In the work presented, synthesis of PEG based hydrogels, characterization of synthesized hydrogels and usage of these hydrogels in controlled drug release systems were studied. Methods: Synthesis of PEG based hydrogels having different properties was done by free radical photopolymerization by using a photoinitiator . In this stage because of their biocompatibility, poly ethylene glycol Diacrylate (PEG-DA) as macromer; ethylene glycol dimetacrylate (EGDMA) as cross-linker and 2,2 dimetoxy-2 phenylacetophenon (DMPA) as photoinitiator were used. The macromer amounts of 30, 50 and 100%, cross-linker ratio of 0.25, 1.0 and 3% and photoinitiator ratio of 0.1, 0.5 and 1% by weight were selected. In this scope, dynamic swelling behaviour of hydrogels and their suitability for controlled drug release were tested. The surface characterization of the hydrogels was performed by Attenuated Total Reflectance-Fourier Transfer Infrared Spectroscopy (ATR-FTIR) spectrums. The drug release experiments of dry polymer disks with known weight and known loaded drug amount were performed in pH 7.4 and 1.2 buffer solutions with set ionic strengths, in shaking incubator at 37°C constant temperature with a shaking speed of 100 rpm. In the last part of the work, drug activities of synthesized drug-loaded hydrogels were tested in Staphylococcus aureus and Pseudomonas aeruginosa bacteria cultures. Results: A decrease in swelling degree of hydrogel was observed with an increase in macromer ratio. In the ATR-FTIR spectrums, O-H tension, C-H tension, C=O tension, C-O tension vibration bands which can be said to be a characteristic of PEG-DA hydrogels were observed. The rate of drug release in pH 1.2 was observed to be much faster than pH 7.4 for both types of hydrogels. The transport mechanism in hydrogels was determined by a widely used semi-empirical formula. It was observed that selected drug-loaded hydrogels were effective on inhibition of the reproduction of both bacteria. Conclusion: In the work presented, all of the hydrogels synthesized were found compatible for the controlled drug delivery. Key Words: Photopolymerization, hydogels, controlled drug delivery; PEG. Conflict of Interest:The authors declare no conflict of interest. ÖZETAmaç: Sunulan araştırma kapsamında; PEG bazlı hidrojellerin sentezi, elde edilen hidrojellerin karakterizasyonu ve bu hidrojellerin kontrollü ilaç salım sistemlerinde kullanımlarının incelenmesi amaçlanmıştır. Metod: Farklı özelliklere sahip PEG bazlı hidrojellerin fotopolimerizasyon yöntemi ile fotobaşlatıcı kullanılarak serbest-radikal fotopolimerizasyonuyla sentezi gerçekleştirilmiştir. Bu aşamada yüksek biyouyumluluğu nedeniyle poli(etilenglikol) diakrilat (PEGDA) makromeri; çapraz bağlayıcı olarak etilen glikol dimetakrilat (EGDMA), fotobaşlatıcı olarak ise 2,2-dimetoksi-2-fenilasetofenon (DMPA) kullanılmıştır. Makromer oranı ağırlıkça %30, 50 ve 100; çapraz bağlayıcı oranı ağırlıkça %0.25, 1.0, 3.0; fotobaşlatıcı oranı ağırlıkça %0.1, 0.5 ve 1 değerlerinde değiştirilerek bileşen mikt...

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“…One strategy for targeting orally administered drugs to the colon includes coating drugs with pH-sensitive hydrogels. 11,15 Polymer bonded drugs usually contain one solid drug bonded together in a matrix of a solid polymeric binder. They can be produced by polymerizing a monomer, such as methacrylic acid (MAA), mixed with a particulate drug, by means of a chemical polymerization, such as AIBN or by means of high-energy radiation, such as x-ray or gamma rays.…”

Section: Introductionmentioning

confidence: 99%

Synthesis and Evaluation of Biocompatible pH-Sensitive Hydrogels as Colon-Specific Drug Delivery Systems

Mahkam

Mohammadi

Siadat

2006

Jnl Chinese Chemical Soc

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Because of the growing importance of pH-sensitive hydrogels as drug delivery systems, biocompatible copolymeric hydrogels based N-vinyl-2-pyrrolidinone (NVP) and methacrylic acid (MAA) were designed and synthesized. These hydrogels were investigated for oral drug delivery. Radical copolymerizations of N-vinyl-2-pyrrolidinone (NVP) and methacrylic acid (MAA) with the various ratios of crosslinking agent were carried out at 70°C. Azabisisobutyronitrile (AIBN) was the free-radical initiator employed and Cubane-1,4-dicarboxylic acid (CDA) linked to two 2-hydroxyethyl methacrylate (HEMA) group was the crosslinking agent (CA) used for hydrogel preparations. The hydrogels were characterized by differential scanning calorimetry and FT-IR. Equilibrium swelling studies were carried out in enzymefree simulated gastric and intestinal fluids (SGF and SIF, respectively). A model drug, olsalazine [3,3¢-azobis (6-hydroxy benzoic acid)] (OSZ) as an azo derivative of 5-aminosalicylic acid (5-ASA), was entrapped in these gels and the in-vitro release profiles were established separately in both enzyme-free SGF and SIF. The drug-release profiles indicated that the amount of drug released depended on the degree of swelling. The swelling was modulated by the amount of crosslinking of the polymer bonded drug (PBDs) prepared. Based on the great difference in hydrolysis rates at pH 1 and 7.4, these pH-sensitive hydrogels appear to be good candidates for colon-specific drug delivery.

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Controlled Release of Biomolecules from pH-sensitive Network Polymers Prepared by Radiation Polymerization

Cited by 22 publications

References 13 publications

Synthesis and characterization of acrylic type hydrogels containing azo derivatives of 5-amino salicylic acid for colon-specific drug delivery

Synthesis and characterization of acrylic type hydrogels containing azo derivatives of 5-amino salicylic acid for colon-specific drug delivery

Photocrosslinked Poly(Ethylen Glycol) Hydrogels for Controlled Drug Delivery

Synthesis and Evaluation of Biocompatible pH-Sensitive Hydrogels as Colon-Specific Drug Delivery Systems

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