Kamarza Mulia, Kamarza
Department Of Chemical Engineering, Universitas Indonesia, Depok 16424, Indonesia

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Enhanced Drug Release of Poly(lactic-co-glycolic Acid) Nanoparticles Modified with Hydrophilic Polymers: Chitosan and Carboxymethyl Chitosan Diah Lestari; Noverra Mardhatillah Nizardo; Kamarza Mulia
Indonesian Journal of Chemistry Vol 22, No 5 (2022)
Publisher : Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22146/ijc.73673

Abstract

The biodegradable polymer poly(lactic-co-glycolic acid) (PLGA) is a biomaterial with great potential as a drug delivery carrier and a tissue engineering scaffold. Using diclofenac sodium (DS) as a drug model, PLGA/DS nanoparticles were synthesized by modification with two hydrophilic polymers: chitosan and carboxymethyl chitosan (CMCh). The introduction of chitosan and CMCh enhances the efficiency encapsulation, capacity loading of the nanoparticles, and DS release at pH 6.8 and minimum release at pH 1.2. Synthesis of nanoparticles was carried out using a double emulsion (water/oil/water) solvent evaporation method. Characterization using an Attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectrophotometer indicates that the interaction between DS and polymer on nanoparticles is non-covalent with a spherical shape based on a transmission electron microscope (TEM) and scanning electron microscope (SEM) characterization. From the various formulation studied, nanoparticles with the ratio chitosan-PLGA-DS and CMCh-PLGA-DS of 2:20:4 proved to be the optimum model carrier with the required release profile and could be the alternative for DS delivery systems.
Simultaneous photoelectrocatalytic hydrogen production and ammonia degradation using titania nanotube-based photoanodes Elysabeth, Tiur; Dewi, Eniya Listiani; Ratnawati; Mulia, Kamarza; Slamet
Communications in Science and Technology Vol 9 No 2 (2024)
Publisher : Komunitas Ilmuwan dan Profesional Muslim Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.21924/cst.9.2.2024.1464

Abstract

The primary focus of this research is to enhance the efficiency and effectiveness of the photoanode based of titania nanotubes in the photoelectrocatalytic process, which enables the simultaneous generation of hydrogen and degradation of ammonia. The modification process involved the incorporation of nitrogen dopant during anodization and sensitization of CuO through Successive Ionic Layer Adsorption Reaction (SILAR). The results of this study showed that the introduction of N dopant led to a significant enhancement in both the ammonia elimination and the hydrogen production, as evidenced by 3N-TiNTAs achieving 74.4% and 561 mmol/m2, respectively. Meanwhile, the highest hydrogen production was observed with 7CuO-TiNTAs at 910.14 mmol/m2. The study revealed that N-TiNTAs exhibited superior performance in ammonia degradation; while CuO-TiNTAs showed higher hydrogen production rates. Furthermore, the mechanistic aspects of the study were also thoroughly examined.
Wax Precipitation in Crude Oil by Coutinho Model Based on Conventional Gas Chromatography Data Muh Kurniawan; Adiwar Adiwar; Kamarza Mulia; Chairil Anwar
Scientific Contributions Oil and Gas Vol 36 No 2 (2013)
Publisher : Testing Center for Oil and Gas LEMIGAS

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.29017/SCOG.36.2.764

Abstract

Wax precipitation in crude oils can produce problems in oil production and transportation operations. Prediction is the key of avoidance or remediation of the wax problem of flow assurance. Among the wax prediction thermodynamic model, Coutinho model can be run using limited laboratory data, but the result is comparably accurate. The model requires n-paraffin distribution, which commonly determined by high-temperature gas chromatography (HTGC) analysis. However, only few laboratories could perform the HTGC. Lemigas has abundant database of crude oil with conventional gas chromatography data. An extended n-paraffin distribution was calculated based on the conventional GC data by performing extrapolation and normalization to total wax content. The n-paraffin distribution was applied in Coutinho model to predict wax precipitation of a crude oil sample. The WAT obtained from the model deviated only 2°C from DSC data. The result was also valid to DSC data in term of precipitated wax amount along temperature range.