Browsing by Author "Shakoor, I. F."

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In vitro release of curcumin from alginate submicron particles at pH 2 and pH 6.8
(4th International Research Symposium on Pure and Applied Sciences, Faculty of Science, University of Kelaniya, Sri Lanka, 2019) Shakoor, I. F.; Pamunuwa, G.; Karunaratne, D. N.
Alginate is a polysaccharide, a structural component of marine brown algae that has been used for slow or controlled delivery of incorporated materials in food research due to its biodegradability, biocompatibility and non-toxicity. Although a few studies of alginate nanoparticles encapsulating curcumin, which is a natural product with numerous bioactivities, have been reported, their release kinetics have not been evaluated. Thus, the aim of this study was to evaluate the release behaviour of free curcumin and encapsulated curcumin in gastric pH and intestinal pH for evaluating their suitability for oral delivery. Curcumin encapsulated submicron particles were prepared by using the ionic gelation method and the cross linker used was calcium chloride. The particles were characterized for encapsulation efficiency, loading capacity, size, polydispersity index and zeta-potential. The morphology of the particles were observed via Scanning Electron Microscopy (SEM) while the encapsulation of curcumin was identified via Fourier Transform Infrared Spectroscopy (FTIR). In vitro release studies were conducted at simulated gastro-intestinal pH conditions without enzymes by using the dialysis bag method at 37±2 °C for a period of eight hours. The encapsulation efficiency and loading capacity were 92.78±1.02 % and 0.464±0.005 %, respectively. Average particle size, polydispersity index and zeta potential were 522.9 nm, 114.0 % and -14.7±7.45 mV, respectively. FTIR indicated the encapsulation of curcumin in to the alginate matrix. SEM indicated the formation of spherical particles. Compared to the release of free curcumin, slow and controlled release of curcumin was observed from the submicron particles at both pH conditions, as revealed by UV-visible spectroscopy. At pH 2, maximum release of free curcumin was around 38 % at the eighth hour. However, free curcumin showed a burst release within two hours that approximated to 60 % which was followed by a gradual degradation indicating the inherent instability of curcumin at high pH conditions. However, cumulative release of encapsulated curcumin was less than 16 % throughout the release time period at pH 2 whereas it was 64 % at pH 6.8 by the end of the eight hour experimental period. This result indicates a possible protective role of the particles on encapsulated curcumin. Also, release of encapsulated curcumin was much slower in gastric pH than in intestinal pH, which indicates that alginate submicron particles may be excellent carriers for safe oral delivery of curcumin to the site of its absorption
Release of curcumin from chickpea protein submicron particles at gastrointestinal pH values
(4th International Research Symposium on Pure and Applied Sciences, Faculty of Science, University of Kelaniya, Sri Lanka, 2019) Shakoor, I. F.; Pamunuwa, G.; Karunaratne, D. N.
Activity of bioactive components such as curcumin, which is a natural polyphenolic compound, depends on their stability, solubility, absorption and bioavailability at specific sites. Development of natural polymer based oral delivery systems for controlled delivery of bioactives has become essential in order to improve the aforementioned characteristics of those compounds. Among the biopolymers used in the formation of delivery vehicles, protein holds a prominent place due to its high biocompatibility and biodegradability. Chickpea (Cicer arietinum L.) protein shows high protein bioavailability and it has been used successfully in drug encapsulation processes. Therefore, the purpose of the study was to develop curcumin-loaded submicron particles using chickpea protein, and to characterize, and to evaluate the release of curcumin via understanding its release kinetics from the protein matrix. To prepare chickpea protein isolates, alkaline extraction and subsequent precipitation of the proteins at the isoelectric point (4.5) was followed. Glyoxal was used as a cross-linker. In vitro release studies were carried out using the dialysis bag method, using UV-visible spectroscopy for quantification, at simulated gastric and intestinal pH buffers without enzymes. The release profiles were fitted in to eight different mathematical models namely Zero order, First order, Higuchi, Hixon-Crowell, Korsemeyer-Peppas, Baker-Lonsdale, Weibull and Gompertz, to determine and interpret the kinetics of the drug release from the protein matrix. Encapsulation efficiency showed a high value of 89 % and loading capacity approximated to 0.45 %. Average particle size, polydispersity index and zeta potential were found to be 466.9 nm, 290.5 % and -10.8 mV, respectively. Release of curcumin from the protein matrix showed a slower controlled release compared to the release of free curcumin at both pHs. Release of encapsulated curcumin at pH 2 showed a much higher release compared to the release at pH 6.8. In fact, maximum release at pH 2 and pH 6.8 were approximately 26 % and 16 % at the sixth hour, respectively. Release profiles of curcumin encapsulated protein fitted well with Higuchi and Weibull models at pH 2 and 6.8, respectively. At pH 6.8, release followed a Weibull sigmoidal pattern showing an asymptotic maximal release. At pH 2, release of encapsulated curcumin followed a diffusional release from the matrix. This study indicates differential release behaviour of curcumin from chickpea delivery vehicles at gastric and intestinal pH conditions