Fabrication of Transdermal Patch from Freeze-dried Agarose Hydrogel for Electrically Controlled Release

The main objective of this study was to fabricate biopolymer-based microbeads, providing enteric properties and controlled release of diclofenac sodium, using layer-by-layer technique. The calcium pectinate microbeads have been designed and coated with chitosan and pectin multilayers. Drug release was performed in simulate gastric fluid (pH 1.2) for 2 hours, followed by pH 6.8 buffer for 8 hours. The effects of chitosan concentration, number of layer and drying technique on drug release were investigated. The results showed that the calcium pectinate microbeads could be simply prepared by ionotropic gelation and then coated with chitosan and pectin solutions using layer-by-layer procedure. The diameter of the microbeads ranged from 800 to 1000 μm for air-dried samples and from 1 to 2 mm for freeze-dried samples. The freeze-dried microbeads had a rough surface and many pores inside, as observed by SEM. The microbeads coated with 4% chitosan/4% pectin revealed a slower drug release than those coated with 1% chitosan/4% pectin and demonstrated a controlled release pattern. Moreover, different drying techniques and numbers of layer also influenced drug release behavior of the prepared microbeads.

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Effect of pH and Freezing Condition on Cryogel Encapsulation of Curcumin

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1103.9 ◽

2015 ◽

Vol 1103 ◽

pp. 9-14

Author(s):

Nataporn Sowasod ◽

Kyuya Nakagawa ◽

Tawatchai Charinpanitkul ◽

Wiwut Tanthapanichakoon

Keyword(s):

Controlled Release ◽

Pore Size ◽

Cooling Rate ◽

Colloidal Suspension ◽

Alkaline Media ◽

Freeze Dried ◽

Microstructural Morphology ◽

Freezing Condition ◽

Rate Type

The aim of this study was to develop a pH-sensitive ternary system of chitosan, κ-carrageenan, and carboxymethylcellulose sodium salt (CMC) that can serve as a controlled release system. Encapsulation of curcumin in chitosan was achieved by transforming the present colloidal suspension into hydrogels via cryotropic gel formation. The frozen hydrogel specimens (cryogels) were freeze-dried for preservation and investigation. It was reported that, when the ratio of κ-carrageenan to NaCMC was kept constant, the cooling rate was found to determine the type of release between burst type and controlled first-order-rate type [1]. The microstructural morphology of freeze-dried specimens was observed with a Scanning Electron Microscope (SEM) to be affected by the cooling rate. The faster cooling rate produced specimens with slightly larger pore size and, as a result, higher amount of curcumin released at 2 days. Swelling tests of the hydrogels in buffer solutions of different pH values showed that acidic media had a pronounced effect on swelling compared to the neutral and alkaline media. The faster cooling rate produced specimens that had higher structural strength against swelling despite the fact that the specimens had larger pore size and faster controlled release rate.

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Characterization and Dissolution Study of Chitosan Freeze-Dried Systems for Drug Controlled Release

Molecules ◽

10.3390/molecules14114370 ◽

2009 ◽

Vol 14 (11) ◽

pp. 4370-4386 ◽

Cited By ~ 40

Author(s):

Roberto Ruiz-Caro ◽

María Dolores Veiga-Ochoa

Keyword(s):

Controlled Release ◽

Drug Controlled Release ◽

Dissolution Study ◽

Freeze Dried

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Preparation of Microencapsulated Symbiotic Complex of Probiotics based on Lactobacillus helveticus using Alginate and Chitosan

Biotekhnologiya ◽

10.21519/0234-2758-2020-36-2-56-63 ◽

2020 ◽

Vol 36 (2) ◽

pp. 56-63

Author(s):

D.K. Toropov ◽

T.S. Egorova

Keyword(s):

Biological Activity ◽

Gastrointestinal Tract ◽

Controlled Release ◽

Bacterial Colonization ◽

Lactobacillus Helveticus ◽

Aggressive Environment ◽

Aggressive Action ◽

Freeze Dried ◽

Complex Equipment ◽

Extrusion Method

Various technologies for producing different forms of probiotic preparations including Vitaflor have been compared. This preparation was created based on two symbiotic Lactobacillus helveticus strains, D-75 and D-76, with proven effects of syntrophy and synergism. It is produced in the form of freeze-dried lactobacilli biomass. It was shown that the biological activity of Vitaflor in an aggressive environment of the gastrointestinal tract (GET) was reduced to a level that excluded both bacterial colonization and therapeutic effect. Alginate-chitosan microcapsules containing the Vitaflor symbiotic complex protected the microorganisms from the aggressive action of the GET medium and provided their time-controlled release. The emulsion encapsulation turned out to be most effective: the protection of live lactobacilli was 5 orders of magnitude higher than that in the Vitaflor preparation and 3 orders of magnitude higher than with the extrusion method of obtaining microcapsules. The emulsion encapsulation developed for Vitaflor can be applied to other microorganisms; the technique is rather simple, easily scalable and does not require complex equipment. probiotics, Lactobacillus helveticus, microencapsulation technology, natural polysaccharides, alginate, chitosan

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The role of carboxyl group of pressure sensitive adhesive in controlled release of propranolol in transdermal patch: Quantitative determination of ionic interaction and molecular mechanism characterization

European Journal of Pharmaceutical Sciences ◽

10.1016/j.ejps.2018.01.038 ◽

2018 ◽

Vol 115 ◽

pp. 330-338 ◽

Cited By ~ 9

Author(s):

Degong Yang ◽

Xiaocao Wan ◽

Peng Quan ◽

Chao Liu ◽

Liang Fang

Keyword(s):

Controlled Release ◽

Quantitative Determination ◽

Molecular Mechanism ◽

Carboxyl Group ◽

Transdermal Patch ◽

Ionic Interaction ◽

Pressure Sensitive Adhesive ◽

Pressure Sensitive

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Microfluidic spray dried and spray freeze dried uniform microparticles potentially for intranasal drug delivery and controlled release

Powder Technology ◽

10.1016/j.powtec.2020.10.061 ◽

2021 ◽

Vol 379 ◽

pp. 144-153

Author(s):

Aijun Di ◽

Shengyu Zhang ◽

Xuan Liu ◽

Zhenbo Tong ◽

Siping Sun ◽

...

Keyword(s):

Drug Delivery ◽

Controlled Release ◽

Intranasal Drug Delivery ◽

Freeze Dried ◽

Spray Dried

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Smart Freeze-Dried Bigels for the Prevention of the Sexual Transmission of HIV by Accelerating the Vaginal Release of Tenofovir during Intercourse

Pharmaceutics ◽

10.3390/pharmaceutics11050232 ◽

2019 ◽

Vol 11 (5) ◽

pp. 232 ◽

Cited By ~ 7

Author(s):

Araceli Martín-Illana ◽

Fernando Notario-Pérez ◽

Raúl Cazorla-Luna ◽

Roberto Ruiz-Caro ◽

María Dolores Veiga

Keyword(s):

Controlled Release ◽

Seminal Fluid ◽

Sexual Transmission ◽

Antiretroviral Drugs ◽

African Women ◽

Vaginal Fluid ◽

Freeze Dried ◽

Route Of Transmission ◽

Sub Saharan ◽

Sexual Transmission Of Hiv

Sub-Saharan African women are still at risk from the human immunodeficiency virus (HIV), and sex with men is the main route of transmission. Vaginal formulations containing antiretroviral drugs are promising tools to give women the power to protect themselves. The aim of this work was to obtain freeze-dried bigels containing pectin, chitosan, or hypromellose for the vaginal controlled release of Tenofovir, which is accelerated in the presence of semen. Nine batches of bigels were formulated using different proportions of these polymers in the hydrogel (1, 2, and 3% w/w). The bigels obtained were freeze-dried and then underwent hardness and deformability, mucoadhesion, swelling, and drug release tests, the last two in simulated vaginal fluid (SVF) and SVF/simulated seminal fluid (SSF) mixture. The formulation containing 3% pectin (fd3P) has the highest values for hardness, resistance to deformation, and good mucoadhesivity. Its swelling is conditioned by the pH of the medium, which is responsive to the controlled release of Tenofovir in SVF, with the fastest release in the SVF/SSF mixture. fd3P would be an interesting smart microbicidal system to allow faster release of Tenofovir in the presence of semen, and thus increase women’s ability to protect themselves from the sexual transmission of HIV.

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