Application of the protein-polymer interaction for the formation of microcapsules with controlled release of the active substance

Mikrokapsule, kao nosači aktivnih supstanci, imaju sve veću primenu u različitim granama industrije, naročito prehrambene i farmaceutske. Inkorporiranje biološki aktivnih supstanci unutar mikrokapsula omogućava maskiranje neprijatnih mirisa i ukusa, zaštitu osetljivih i lako isparljivih komponenata. Cilj ove doktorske disertacije je dobijanje mikrokapsula za istovremeno inkorporiranje hidrosolubilnih i liposolubilnih aktivnih materija, radi njihove zaštite i kontrolisanog otpuštanja. Mikrokapsule su formirane iz duplih emulzija tipa voda-ulje-voda (V/U/V) metodom koacervacije, odnosno deponovanjem koacervata, koji nastaje u sistemu dva suprotno naelektrisana proteina, želatina i natrijum kazeinata (NaKN), na granicu faza ulje/voda. Kao model supstance za hidrosolubilne i liposolubilne biološki aktivne materije, korišćeni su vitamini C i E. Najpre su detaljno ispitane interakcije u sistemu želatin/NaKN primenom različitih metoda (merenje zeta potencijala, tenziometrija, viskozimetrija, reološka ispitivanja). Na osnovu ovih rezultata definisane su promene, kako na granici faza, tako i unutar rastvora, kao i mehanizama formiranja koacervata između ova dva suprotno naelektrisana proteina. Utvrđeno je da se pri masenom odnosu želatin:NaKN od 2:1 dolazi do formiranja nerastvornog koacervata. Ispitan je uticaj interakcija u ovom sistemu na osobine duplih, V/U/V emulzija dobijenih emulgovanjem primarnih voda/ulje (V/U) emulzija u smeši želatin/NaKN, pri njihovim odabranim masenim odnosima i zaključeno je da interakcija između proteina u kontinualnoj fazi utiče na osobine emulzija. S obzirom da je prvi korak ka dobijanju stabilne V/U/V emulzije, dobijanje stabilne primarne V/U emulzije, ispitana je mogućnost primene lipofilnih emulgatora, poliglicerol poliricinoleata (PGPR) i poliglicerol estra jestivih masnih kiselina i njihovih smeša, za dobijanje 20% V/U emulzija. Ispitivanjem uticaja sastava smeše emulgatora i njegove koncentracije na formiranje adsorpcionog sloja na graničnoj površini ulje/voda i osobine formiranih V/U emulzija odabran je najpogodniji sistem za stabilizaciju primarnih emulzija. Nakon formulisanja stabilnih duplih V/U/V emulzija sa inkorporiranim vitaminima C i E, optimizovani su uslovi za dobijanje mikrokapsula umrežavanjem kompleksa proteina na kapima ulja pomoću genipina, a njihovo izdvajanje iz rastvora ostvareno je primenom Spray drying postupka. Karakterizacijom dobijenih mikrokapsula (ispitivanjem morfologije površine, efikasnosti inkapsulacije vitamina C i E, kinetike otpuštanja vitamina C u in vitro uslovima) zaključeno je da na osobine mikrokapsula utiče koncentracija umreživača, kao i interakcija između želatina i NaKN u kontinualnoj fazi emulzija V/U/V.Microcapsules, as active substance carriers, have increasing application in different industries, especially in food and pharmaceutical industry. Incorporation of the biologically active substances inside the microcapsules allows masking of unpleasant taste and smell, protection od sensitive and volatile components. The aim of this thesis is preparation of microcapsules for parallel incorporation of water and oil soluble active substances for their protection and controlled release. Microcapsules were formed from double water-oil-water emulsions (W/O/W) by coacervation method, depositing the coacervate formed in the system of two oppositely charged proteins, gelatin and sodium caseinate (NaCN), at the water/oil interface. As a model for water and oil soluble biological active substances, vitamins C and E were used. First of all, interactions in the gelatin/NaCN system were investigated in detail, by using different methods (measuring of zeta potential, tensiometry, vicometry, rheological investigations). Based on these results, changes at the interface and in the bulk of the system, as well as mechanisms of coacervate formation were defined. It has been determined that at gelatin:NaCN mass ratio of 2:1 non soluble coacervate were formed. Influence of the interactions in this system on properties of the W/O/W double emulsions, made by emulsification of primary water/oil (W/O) emulsions in gelatin/NaCN mixtures, at desired mass ratios of proteins, was investigated. It was concluded that interactions between proteins in continuous phase of emulsions have influence on their properties. As the first step in formation of stable W/O/W emulsions is obtaining stable primary W/O emulsion, possibility of using lipophilic emulsifiers, polyglycerol polyricinoleate (PGPR) and polyglycerol esters of edible fatty acids and their mixtures, for 20% W/O emulsions formation were investigated. Results of these investigations showed that composition of emulsifiers mixtures and their concentrations have an influence on adsorption layer, at the water/oil interface, formation, as well as on stability of W/O emulsion, and based on these results the most suitable system of emulsifiers were chosen. After formulation of stable double W/O/W emulsions with incorporated vitamins C and E, conditions for microcapsules formation, by crosslinking of proteins complex at oil droplets with genipin, were optimized, and for their separation from dispersion spray drying method was applied. Characterization of obtained microcapsules (investigation of the surface morphology, efficiency of the vitamins C and E encapsulation, release kinetics of vitamin C under in vitro conditions) showed that concentration of crosslinking agent, as well as interaction between gelatin and NaCN, have an influence on microcapsules properties

Application of the protein-polymer interaction for the formation of microcapsules with controlled release of the active substance

Mikrokapsule, kao nosači aktivnih supstanci, imaju sve veću primenu u različitim granama industrije, naročito prehrambene i farmaceutske. Inkorporiranje biološki aktivnih supstanci unutar mikrokapsula omogućava maskiranje neprijatnih mirisa i ukusa, zaštitu osetljivih i lako isparljivih komponenata. Cilj ove doktorske disertacije je dobijanje mikrokapsula za istovremeno inkorporiranje hidrosolubilnih i liposolubilnih aktivnih materija, radi njihove zaštite i kontrolisanog otpuštanja. Mikrokapsule su formirane iz duplih emulzija tipa voda-ulje-voda (V/U/V) metodom koacervacije, odnosno deponovanjem koacervata, koji nastaje u sistemu dva suprotno naelektrisana proteina, želatina i natrijum kazeinata (NaKN), na granicu faza ulje/voda. Kao model supstance za hidrosolubilne i liposolubilne biološki aktivne materije, korišćeni su vitamini C i E. Najpre su detaljno ispitane interakcije u sistemu želatin/NaKN primenom različitih metoda (merenje zeta potencijala, tenziometrija, viskozimetrija, reološka ispitivanja). Na osnovu ovih rezultata definisane su promene, kako na granici faza, tako i unutar rastvora, kao i mehanizama formiranja koacervata između ova dva suprotno naelektrisana proteina. Utvrđeno je da se pri masenom odnosu želatin:NaKN od 2:1 dolazi do formiranja nerastvornog koacervata. Ispitan je uticaj interakcija u ovom sistemu na osobine duplih, V/U/V emulzija dobijenih emulgovanjem primarnih voda/ulje (V/U) emulzija u smeši želatin/NaKN, pri njihovim odabranim masenim odnosima i zaključeno je da interakcija između proteina u kontinualnoj fazi utiče na osobine emulzija. S obzirom da je prvi korak ka dobijanju stabilne V/U/V emulzije, dobijanje stabilne primarne V/U emulzije, ispitana je mogućnost primene lipofilnih emulgatora, poliglicerol poliricinoleata (PGPR) i poliglicerol estra jestivih masnih kiselina i njihovih smeša, za dobijanje 20% V/U emulzija. Ispitivanjem uticaja sastava smeše emulgatora i njegove koncentracije na formiranje adsorpcionog sloja na graničnoj površini ulje/voda i osobine formiranih V/U emulzija odabran je najpogodniji sistem za stabilizaciju primarnih emulzija. Nakon formulisanja stabilnih duplih V/U/V emulzija sa inkorporiranim vitaminima C i E, optimizovani su uslovi za dobijanje mikrokapsula umrežavanjem kompleksa proteina na kapima ulja pomoću genipina, a njihovo izdvajanje iz rastvora ostvareno je primenom Spray drying postupka. Karakterizacijom dobijenih mikrokapsula (ispitivanjem morfologije površine, efikasnosti inkapsulacije vitamina C i E, kinetike otpuštanja vitamina C u in vitro uslovima) zaključeno je da na osobine mikrokapsula utiče koncentracija umreživača, kao i interakcija između želatina i NaKN u kontinualnoj fazi emulzija V/U/V.Microcapsules, as active substance carriers, have increasing application in different industries, especially in food and pharmaceutical industry. Incorporation of the biologically active substances inside the microcapsules allows masking of unpleasant taste and smell, protection od sensitive and volatile components. The aim of this thesis is preparation of microcapsules for parallel incorporation of water and oil soluble active substances for their protection and controlled release. Microcapsules were formed from double water-oil-water emulsions (W/O/W) by coacervation method, depositing the coacervate formed in the system of two oppositely charged proteins, gelatin and sodium caseinate (NaCN), at the water/oil interface. As a model for water and oil soluble biological active substances, vitamins C and E were used. First of all, interactions in the gelatin/NaCN system were investigated in detail, by using different methods (measuring of zeta potential, tensiometry, vicometry, rheological investigations). Based on these results, changes at the interface and in the bulk of the system, as well as mechanisms of coacervate formation were defined. It has been determined that at gelatin:NaCN mass ratio of 2:1 non soluble coacervate were formed. Influence of the interactions in this system on properties of the W/O/W double emulsions, made by emulsification of primary water/oil (W/O) emulsions in gelatin/NaCN mixtures, at desired mass ratios of proteins, was investigated. It was concluded that interactions between proteins in continuous phase of emulsions have influence on their properties. As the first step in formation of stable W/O/W emulsions is obtaining stable primary W/O emulsion, possibility of using lipophilic emulsifiers, polyglycerol polyricinoleate (PGPR) and polyglycerol esters of edible fatty acids and their mixtures, for 20% W/O emulsions formation were investigated. Results of these investigations showed that composition of emulsifiers mixtures and their concentrations have an influence on adsorption layer, at the water/oil interface, formation, as well as on stability of W/O emulsion, and based on these results the most suitable system of emulsifiers were chosen. After formulation of stable double W/O/W emulsions with incorporated vitamins C and E, conditions for microcapsules formation, by crosslinking of proteins complex at oil droplets with genipin, were optimized, and for their separation from dispersion spray drying method was applied. Characterization of obtained microcapsules (investigation of the surface morphology, efficiency of the vitamins C and E encapsulation, release kinetics of vitamin C under in vitro conditions) showed that concentration of crosslinking agent, as well as interaction between gelatin and NaCN, have an influence on microcapsules properties

Chitosan/sodium lauryl ether sulfate microcapsules as carriers for vitamin E: in vitro release study

INTRODUCTION: The important current focus in production of cosmetics is usage of vitamin E (E), a natural antioxidant protective for tissues from UV radiation, delays photoaging and provide moisturizing effect. Encapsulation is needed for its protection from high temperature, oxygen, and light, during storage, and also for a potential ability to control its release and delivery. Preparation of microcapsules of desired characteristics depends on various factors (size and nature of the core substance, wall material, techniques and parameters of encapsulation) [1, 2]. The study aimed to evaluate chitosan/sodium lauryl ether sulfate (Ch/SLES) microcapsules with E as a delivery system for skin care. MATERIALS AND METHODS: Microcapsules were prepared by complex coacervation. Initially, a 20% O/W emulsion with E (10% solution in medium-chain triglycerides), stabilized with the mixture of Ch (0.1 %) and SLES [3], was obtained by Ultra Turrax T25 homogenization. The emulsion, without or with a crosslinker, formaldehyde (FA) or glutaraldehyde (GA), was spray dried. The in vitro release profile of E from the microcapsule samples (0.1 g) was studied in 100 g of ethanol 80%, under continuous stirring at room temperature. The dissolved E in supernatant aliquots (2 ml) was analyzed during 90 min, by the Halo DB-20S UV-VIS spectrophotometer. RESULTS: The obtained release profiles were analyzed by fi tt ing in different mathematical models and in all samples correlate the best with Korsmeyer-Peppas model. The diffusion exponent n values (0.05-0.23) indicated non-Fickian diffusion. We assumed that release of E was based on a combination of rinsing from the surface of the microcapsules [4] and diffusion through the capsule wall. For microparticles with GA, n was the lowest, the release was rapid and the amount of release of the substance was higher (i.e., more pronounced rinsing process), compared with FA and microcapsules without the crosslinker, where release of E was more controlled by diffusion. CONCLUSION: E vitamin release from Ch/ SLES microcapsules followed Korsmeyer-Peppas kinetics. The selection of the crosslinker influenced their surface properties, the surface amount and permeability of the capsule wall for E vitamine diffusion.12th Central European Symposium on Pharmaceutical Technology and Regulatory Affairs and Satellite Symposium on Pharmaceutical Biotechnology (12th CESPT), Szeged, Hungary, 20th-22nd September 2018.Saopštenje sa međunarodnog skupa štampano u izvod

Composite chitosan hydrogels as advanced wound dressings with sustained ibuprofen release and suitable application characteristics

The physical chitosan hydrogel, obtained by ionic gelation in lactic acid solution, was combined with biocompatible oil-in-water microemulsion with ibuprofen, to prepare composite hydrogels with 0.25–1% of the polymer and 5% of the drug. The electrical conductivity measurement, photon correlation spectroscopy (PCS), and rheological analysis showed that the composite hydrogels comprise oil nanodroplets (16.21–22.56 nm) embedded within pseudoplastic chitosan hydrogel. In vitro ibuprofen release was sustained for 12 h and followed zero-order kinetics. pH values of the composite hydrogels were in the range of 4.80–5.27, thus physiologically acceptable. The formulation containing 0.5% chitosan enabled the maximum drug release rate of 239.25 μgh−1cm−2 as well as cohesiveness (154.958 ± 0.731 g*s) higher than hardness (13.546 ± 0.065 g) and adhesiveness (−12.042 ± 1.161 g*s), so textural properties were suitable for application along skin surface, without spillage, and for easy removal. This is the first study in which the composite chitosan hydrogels with ibuprofen were formulated by combining the chitosan hydrogel prepared without harmful chemical crosslinkers and low viscosity oil-in-water microemulsion, and the preclinical characterization of their biopharmaceutical aspect and textural characterization, that is of key importance in improving the patient’s compliance, were performed

Carbomer Hydrogels with Microencapsulated α-Tocopherol: Focus on the Biocompatibility of the Microcapsules, Topical Application Attributes, and In Vitro Release Study

The microencapsulation of α-tocopherol based on the complex coacervation of low-molecular-weight chitosan (LMWC) and sodium lauryl ether sulphate (SLES) without harmful crosslinkers can provide biocompatible carriers that protect it from photodegradation and air oxidation. In this study, the influence of the microcapsule wall composition on carrier performance, compatibility with a high-water-content vehicle for topical application, and release of α-tocopherol were investigated. Although the absence of aldehyde crosslinkers decreased the encapsulation efficiency of α-tocopherol (~70%), the variation in the LMWC/SLES mass ratio (2:1 or 1:1) had no significant effect on the moisture content and microcapsule size. The prepared microcapsule-loaded carbomer hydrogels were soft semisolids with pseudoplastic flow behavior. The integrity of microcapsules embedded in the hydrogel was confirmed by light microscopy. The microcapsules reduced the pH, apparent viscosity, and hysteresis area of the hydrogels, while increasing their spreading ability on a flat inert surface and dispersion rate in artificial sweat. The in vitro release of α-tocopherol from crosslinker-free microcapsule-loaded hydrogels was diffusion-controlled. The release profile was influenced by the LMWC/SLES mass ratio, apparent viscosity, type of synthetic membrane, and acceptor medium composition. Better data quality for the model-independent analysis was achieved when a cellulose nitrate membrane and ethyl alcohol 60% w/w as acceptor medium were used

Encapsulation and release of vitamin C in double W/O/W emulsions followed by complex coacervation in gelatin-sodium caseinate system

The objective of this study was to produce and characterize microcapsules for simultaneous encapsulation hydrophilic and lipophilic active substances. For this purpose, double emulsification process was employed, followed by complex coacervation in the system of two oppositely charged biopolymers, gelatin and sodium caseinate (NaCAS). Properties of the microcapsules wall have been regulated by cross-linking of the gelatin/NaCAS complex at the interface with genipin. Vitamins C and E were selected as model hydrophilic and lipophilic bioactive compounds for this study. Investigations of surface morphology, encapsulation efficiency (EE) and kinetic of vitamin C release have shown that genipin concentration as well as interaction in gelatin/NaCAS system make an influence on microcapsules properties. Genipin concentration of 2 mmol/g, was chosen as the optimal and the highest EE of the vitamins were obtained at proteins mass ratio of 2:1. The results of release kinetic determination of the vitamins showed that release mechanism is simple diffusion

Study of vitamin E microencapsulation and controlled release from chitosan/sodium lauryl ether sulfate microcapsules

Potential benefit of microencapsulation is its ability to deliver and protect incorporated ingredients such as vitamin E. Microcapsule wall properties can be changed by adding of coss-linking agents that are usually considered toxic for application. The microcapsules were prepared by a spray-drying technique using coacervation method, by depositing the coacervate formed in the mixture of chitosan and sodium lauryl ether sulfate to the oil/water interface. All obtained microcapsules suspensions had slightly lower mean diameter compared to the starting emulsion (6.85 ± 0.213 μm), which shows their good stability during the drying process. The choice and absence of cross-linking agents had influence on kinetics of vitamin E release. Encapsulation efficiency of microcapsules without cross-linking agent was 73.17 ± 0.64 %. This study avoided the use of aldehydes as cross-linking agents and found that chitosan/SLES complex can be used as wall material for the microencapsulation of hydrophobic active molecules in cosmetic industry