Application of chitosan-ionic surfactant system for the preparation of microcapsules with oil content

Mikrokapsulacija je tehnika kojom se nestabilne, međusobno inkompatibilne i biološki aktivne supstance prevode u stabilniji oblik, ili se omogućuje njihovo kontrolisano i ciljano oslobađanje. Osobine formiranih mikrokapsula, kinetika i mesto otpuštanja inkapsuliranih materija zavise, pre svega, od njihovog omotača. Savremene tendencije razvoja prehrambenih proizvoda i proizvoda farmaceutske i kozmetičke industrije, su sve više usmerene ka upotrebi prirodnih i biorazgradivih polimernih materija za formiranje omotača mikrokapsula. Cilj ove disertacije je mogućnost primene hitozana, netoksičnog, biorazgradivog derivata hitina, kao materije omotača mikrokapsula sa uljnim sadržajem. S obzirom na njegovu slabu površinsku aktivnost, istraživanja su usmerena na primenu interakcija hitozana sa suprotno naelektrisanim jonskim površinski aktivnim materijama (PAM) u vodenim rastvorima, kao mehanizmu za njegovo deponovanje na graničnoj površini ulje/voda. Primenom različitih metoda (tenziometrija, viskozimetrija, turbidimetrija, merenje elektroforetske pokretljivosti) interakcije hitozana sa natrijum-dodecil-sulfatom (SDS) i natrijum-lauriletar-sulfatom (SLES) su detaljno ispitane. Definisane su promene kako na granici faza, tako i unutar rastvora, a mehanizam formiranja kompleksa hitozan/PAM različitih osobina je u potpunosti razjašnjen. Utvrđeno je da do formiranja stabilnog koacervata dolazi pri masenom odnosu hitozan:SLES 1:2 i hitozan:SDS 1:2. Ispitivanje uticaja interakcije hitozan-PAM na osobine emulzionih sistema tipa ulje u vodi (veličina i raspodela veličina kapi, stabilnost) omogućilo je odabir hitozan-SLES sistema kao omotača pogodnog za dobijanje mikrokapsula uljnog sadržaja. Na osnovu ovih rezulatata kao uljna faza odabrani su trigliceridi srednje dužine ugljovodoničnih lanca (TSDL). Sušenjem emulzija primenom spray drying postupka dobijene se mikrokapsule uljnog sadržaja sa vitaminom E i ispitan je uticaj umreživača na njihove osobine. Karakterizacijom dobijenih mikrokapsula (određivanje sadržaja vlage, ispitivanje morfologije površine, efiksanost inkapsulacije vitamina E, kinetika otpuštanja vitamina E u in vitro uslovima) zaključeno je da na osobine mikrokapsula utiče vrsta i koncentracija umreživača. Mikrokapsule čiji omotač nije umrežen pokazale su najbolje karakteristike.Microencapsulation is a technique that unstable, incompatible and biologically active substances converted to a more stable form, or allow their controlled and targeted release. The properties of formed microcapsules, kinetics and the place of release of encapsulated substances, primarly depend on their shell characteristic. Modern trends in the development of food products and products of the pharmaceutical and cosmetic industries are increasingly focused on the use of natural and biodegradable polymeric materials for coatings. The aim of this dissertation is to investigate the possibility of using chitosan, non-toxic and biodegradable chitin derivative, as a shell material of microcapsules with oil content. Due to its low surface activity, the research is focused on the utilization of chitosan interactions with opositly charged ionic surfactants (sodium dodecyl sulfate (SDS) and sodium lauryl ether sulfate (SLES)) in aqueous solutions as mechanisms for its depositing at the oil/water interface. Based on detailed investigation of interactions in the chitosan-ionic surfactant systems using different methods (tensiometry, viscometry, turbidimetry, measurement of electrophoretic mobility), changes have been defined both at the interface and within the bulk, as well as the mechanism of formation of the coacervate phase. It has been determined that at chitosan:SLES and chitosan:SDS mass ratio of 1:2 stabile coacervate were formed. An investigation of the influence of interaction on the properties of oil-in-water emulsion systems (size and distribution of droplet size, stability) enabled the chitosan-SLES system to be selected as a shell suitable for obtaining microcapsules of the oil content. Also, based on these results, medium-chain triglycerides were selected as the oil phase of the emulsion. Microcapsules with vitamin E were obtained by spray drying of emulsions stabilized with chitosan/SLES complex. The influence of the crosslinker on the properties of microcapsules was investigated. Characterization of obtained microcapsules (moisture content determination, investigation of the surface morphology, efficiency of the vitamin E encapsulation, release in vitro kinetics of vitamin E) showed that type and concentration of crosslinking agents had influences the properties of microcapsules. Microcapsules without crosslinking agents have the most suitable characteristics

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

Characterization of escin-loaded chitosan/xanthan-based polyelectrolyte complexes for pH-driven oral drug delivery

Escin is a vasoprotective drug with pH-dependent aqueous solubility, used in the form of gastro-resistant tablets due to its ability to irritate the gastric mucosa. ..

Interactions in escin-loaded chitosan/xanthan-based polyelectrolyte complexes: evaluation of drug content and drying method impact

Escin is an amphiphilic drug with weakly acidic properties, a saponoside with aglycone and glycone parts in the structure. It has high and pH-dependent solubility in water. ..

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

Evaluation of chitosan/xanthan gum polyelectrolyte complexes potential for pH-dependent oral delivery of escin

Escin is an amphiphilic and weakly acidic drug that oral administration may lead to the irritation of gastric mucosa. The entrapment of escin into chitosan (CH)/xanthan gum (XG)-based polyelectrolyte complexes (PECs) can facilitate controlled drug release which may be beneficial for the reduction of its side effects. This study aimed to investigate the influence of escin content and drying method on the formation, physicochemical, and controlled, pH-dependent drug release properties of CH/XG-based PECs. Measurements of transmittance, con- ductivity, and rheological characterization confirmed the formation of CH/XG-based PECs with escin entrapped at escin-to-polymers mass ratios 1:1, 1:2, and 1:4. Ambient-dried PECs had higher yield, entrapment efficiency, and escin content in comparison with spray-dried ones. FT-IR spectra confirmed the interactions between CH, XG, and escin, which were stronger in ambient-dried PECs. PXRD and DSC analyses showed the amorphous escin character in all dry PECs, regardless of the drying method. The most promising controlled and pH-dependent in vitro escin release was from the ambient-dried PEC at the escin-to-polymers mass ratio of 1:1. For that reason and due to the highest yield and entrapment efficiency, this carrier has the potential to prevent the irritation of gastric mucosa after oral administration of escin

Uticaj postupka sušenja raspršivanjem na svojstva polielektrolitnih kompleksa hitozana i ksantan gume kao nosača za peroralnu isporuku ibuprofena

Polyelectrolyte complexes (PECs) are attractive carriers with recognized potential to enhance oral delivery of poorly soluble high-dosed low-molecular-weight drugs. The formulation of solid oral dosage forms requires the drying of PECs, which may affect their physicochemical and biopharmaceutical properties. The aim of this study was to investigate the effect of spray- drying on the properties of ibuprofen-loaded chitosan/xanthan gum PECs and to assess the drug release kinetics from such PECs filled into hard capsules in comparison with corresponding PECs which are dried under ambient conditions. The yield, ibuprofen content, entrapment efficiency, and residual moisture content of spray-dried PECs were lower than those of ambient-dried PECs. Better flowability of spray-dried PECs was attributed to the almost spherical particle shape, shown by scanning electron microscopy. DSC and PXRD analysis confirmed the amorphization of ibuprofen during spray-drying. All the investigated PECs, obtained by drying under ambient conditions as well as by spray-drying, had high rehydration capacity both in 0.1 M hydrochloric acid (pH 1.2) and phosphate buffer pH 7.4. In vitro ibuprofen release from dried PECs was controlled during 12 h with the release of approximately 30% of entrapped ibuprofen. Spray-dried PECs provided better control of ibuprofen diffusion from the carrier compared to the ambient- dried ones.Polielektrolitni kompleksi (PEK) su atraktivni nosači sa potencijalom poboljšanja peroralne isporuke slabo rastvorljivih visokodoziranih lekovitih supstanci niske molekulske mase. Formulisanje čvrstih oralnih farmaceutskih oblika na bazi PEK zahteva njihovo sušenje, što može uticati na fizičko-hemijska i biofarmaceutska svojstva kompleksa. Cilj ove studije bio je da se ispita efekat sušenja raspršivanjem na svojstva PEK hitozana i ksantan gume u koje je inkorporiran ibuprofen i da se proceni kinetika oslobađanja lekovite supstance iz takvih PEK napunjenih u tvrde kapsule u poređenju sa odgovarajućim PEK koji su sušeni pod ambijentalnim uslovima. Prinos, sadržaj ibuprofena, efikasnost inkorporiranja i sadržaj vlage PEK sušenih raspršivanjem bili su niži nego kod PEK sušenih pod ambijentalnim uslovima. Bolja protočnost PEK osušenih raspršivanjem je posledica skoro sfernog oblika čestica, što je pokazano skenirajućom elektronskom mikroskopijom. Rezultati DSC i PXRD analiza su potvrdili amorfizaciju ibuprofena tokom sušenja raspršivanjem. Ispitivani PEK osušeni pod različitim uslovima imali su visoku sposobnost rehidratacije u 0,1 M hlorovodoničnoj kiselini (pH 1,2) i fosfatnom puferu pH 7,4. In vitro oslobađanje ibuprofena iz osušenih PEK bilo je kontrolisano tokom 12 h uz oslobađanje približno 30% inkorporiranog ibuprofena. PEK sušeni raspršivanjem obezbedili su bolju kontrolu difuzije ibuprofena iz nosača u poređenju sa onima sušenim pod ambijentalnim uslovima