Judul: Mikroenkapsulasi Ibuprofen Menggunakan Paduan Lilin Lebah-Pektin dengan Tween 20 sebagai Pengemulsi
Abstrak: Penggunaan ibuprofen dalam jangka panjang dapat menyebabkan efek samping antara lain tukak lambung dan pendarahan pada gastrointestinal. Salah satu cara menanganinya adalah dengan mengenkapsulasi ibuprofen sehingga pelepasannya dapat diperlambat. Penelitian ini bertujuan mengenkapsulasi ibuprofen menggunakan paduan lilin lebah-pektin dengan Tween 20 sebagai pengemulsi. Metode yang digunakan adalah emulsi penguapan pelarut dengan pelarut diklorometana. Rendemen dan efisiensi enkapsulasi teringgi berturut-turut adalah 70% dan 72% didapatkan pada mikrokapsul dengan nisbah lilin lebahpektin 6:4 dan konsentrasi Tween 20 sebesar 1%. Profil disolusi menunjukkan bahwa ibuprofen terlepas secara lambat dari mikrokapsul dengan persen pelepasan 36% setelah 6 jam. Hasil pengamatan morfologi menunjukkan bahwa mikrokapsul memiliki permukaan tidak halus dengan tonjolan-tonjolan yang tidak beraturan. Spektrum inframerah menunjukkan bahwa interaksi yang terbentuk pada mikrokapsul merupakan interaksi fisik.
Keyword: xdisolusi, efisiensi, ibuprofen, mikrokapsul

Judul: Pelepasan Ibuprofen dari Mikrokapsul Tersalut Paduan Lilin Lebah dan Poli(asam laktat) Secara In Vitro
Abstrak: Ibuprofen as an anti-inflammatory drug has a short elimination rate which can causes gastric irritation. Microencapsulation technique can be used to overcome these problems and provide a better therapeutic efficacy through controlled drug release mechanism. In this research, microencapsulation of ibuprofen carried out by blending process and emulsion-solvent evaporation method. Ibuprofen was coated by blend beeswax and poly(lactic acid) (PLA) with various compositions (9:1, 8:2, 7:3, and 6:4) and concentration of gelatin (1%, 1.5%, and 2%) as an emulsifier. Efficiency of encapsulation performed in simulated intestinal medium pH 7.2. The highest value of ibuprofen encapsulation efficiencies was equal to 84.21% had been produced by microcapsules with ratio bees wax:PLA 6:4 and concentration of gelatin 2%. Release test of ibuprofen was performed by beeswax:PLA blend with ratio 8:2 and 6:4 produces the highest average percentage release about 15.31% and 19.25% at minute 225 in the same medium. The release pattern of ibuprofen had followed zero order kinetics model explaining that concentration of ibuprofen released relative constant for each release time. Observation of surface morphology of microcapsules using a scanning electron microscop (SEM) showed subtle bulges irregularly shaped scattered on its surface.
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Judul: Analysis of Unequal Income Distribution with Cobb-Douglas Production Function
Abstrak: This paper studies the economic growth model by Moav (2002). Moav model shows the existence of unequal income distribution between low-income with high-income community. That kind of unequal income distribution is caused by uneven distribution of income. On this Moav model, there is one area called the threshold. Threshold becomes a benchmark to determining whether a society is categorized into low- or high- income community. The production function used in this paper is the Cobb-Douglas function. The dynamics of this model is described as difference equation of low-income, threshold, and high-income community. Simulation study on the model is carried out using Maple 13 and Mathematica 7.0 software. Overall, from the observed case, high-income community will reach a stable condition earlier, followed by the threshold, and then the low-income community.
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