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All Journal Indonesian Journal of Chemistry

Hernawan Hernawan

Technical Implementation Unit For Development Chemical Engineering Processes, Indonesian Institute Of Science, Gading, Playen, Gunungkidul, Yogyakarta 55861

Author-ID : 3957708

Chemical Engineering, Chemistry & Bioengineering Chemistry

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Articles

FORMULATION AND IN VITRO STUDY OF PROPRANOLOL HYDROCHLORIDE CONTROLLED RELEASE FROM CARBOXYMETHYL CHITOSAN-BASED MATRIX TABLETS Hernawan Hernawan; Septi Nurhayati; Khoirun Nisa; A.W. Indrianingsih; Cici Darsih; Muhammad Kismurtono
Indonesian Journal of Chemistry Vol 13, No 3 (2013)
Publisher : Universitas Gadjah Mada

Formulation and in vitro study of propranolol hydrochloride controlled release from carboxymethyl chitosan-based matrix tablets have been conducted. Formulations with various concentrations of carboxymethyl chitosan 2% (F1), 4% (F2), 6% (F3) were done by wet granulation method. Compatibility test was conducted by XRD and FTIR spectroscopy to determine interaction between propranolol hydrochloride and polymer excipients. Dissolution profiles was obtained through in vitro tests release using simulated gastric fluid (without enzymes, pH 1.2) for the first 2 h and followed by simulated intestinal fluid (phosphate buffer solution without enzyme, pH 7.2) for 2 h remaining. The dissolution profile of each formulation was fitted with five kinetics modeling of drug release (zero order, first order, Higuchi, Peppas-Korsmeyer, and Hixson-Crowell). The compatibility test results showed that formulation caused physical interactions between propranolol hydrochloride and polymer excipient but doesn't make crystallinity nature of propranolol hydrochloride disturbed even after formulation. Dissolution profiles of each formulation showed that controlled release of propranolol hydrochloride from the tablet followed Peppas-Korsmeyer model. It is concluded that carboxymethyl chitosan in appropriate proportions is suitable for formulating propranolol hydrochloride controlled release tablets which exhibit Peppas-Korsmeyer release kinetics.

SYNTHESIS OF 2-METHOXY-4,6-DI(PROP-1-ENYL)PHENOL FROM EUGENOL AND ITS ACTIVITY AS AN ANTIOXIDANT Hernawan Hernawan; Bambang Purwono; Tutik Dwi Wahyuningsih
Indonesian Journal of Chemistry Vol 12, No 2 (2012)
Publisher : Universitas Gadjah Mada

Synthesis and antioxidant activity of 2-methoxy-4,6-di(prop-1-enyl) phenol from eugenol have been investigated. Synthesis was conducted through three stages of reaction. The first step was CTAB micellar catalytic O-allylation reaction at room temperature, to give 4-allyl-1-(allyloxy)-2-methoxybenzene (2). Compound (2) was subsequently heated for Claisen rearrangement and produced 2,4-diallyl-6- methoxyphenol (3). The final steps was isomerization of compound (3) in alkaline conditions in ethylene glycol, to yield 2-methoxy-4,6-di(prop-1-enyl) phenol (4). Antioxidant activity test was conducted by TBARS and DPPH methods. TBARS test showed that the compound (4) at a concentration of 50 μM could inhibit the oxidation of linoleic acid shown by the increasing of time lag phase (96 ± 2.94 min), reducing the rate of propagation (± 54.54%) and reducing of malonal dialdehyde (MDA) formation (68.04 ± 0.84%). The DPPH test revealed that compound (4) indicated DPPH free radical scavenging activity with IC50 107.66 μM and comparable with IC50 for BHT 107.37 μM.

ISOLATION AND CHARACTERIZATION OF CHITIN AND CHITOSAN PREPARED UNDER VARIOUS PROCESSING TIMES Crescentiana Dewi Poeloengasih; Hernawan Hernawan; M. Angwar
Indonesian Journal of Chemistry Vol 8, No 2 (2008)
Publisher : Universitas Gadjah Mada

Generally production of chitosan from crustacean shells consists of 4 steps, i.e. deproteinization, demineralization, decolorization and deacetylation. Simplification of chitosan production by elimination of deproteinization and/or demineralization, or reducing of reaction time would give many advantages, e.g. reduction of processing time and cost production due to reduction of chemical and power usage. The objectives of this research were to prepare chitosan under various processing times and to characterize the obtained chitin and chitosan. Chitin was prepared under various deproteinization times (0, 15, 30 min at 90 ºC using NaOH 2N) and demineralization times (0, 15, 30 min at ambient temperature using HCl 2N). Chitin was then bleached using aceton/etanol (1:1) for an hour. Deacetylation was achieved by treatment of chitin under condition at 120 ºC for 5 hr using NaOH 50%. Ash and nitrogen content, and degree of deacetylation of chitosan were evaluated. Demineralization and/or deproteinization times influenced the quality of chitin. Chitin and chitosan prepared without demineralization had white and chalky appearance, whereas the other chitosan were off-white in color. Ash and nitrogen contents of the chitosan products were 0.18 - 32.40% and 3.56 - 7.59%, respectively. Chitosan prepared under various processing times, except chitosan without demineralization treatment, had degree of deacetylation ≥ 70%.

INHIBITION OF HUMAN LOW-DENSITY LIPOPROTEINS OXIDATION BY Hibiscus radiatus CUV. CALYCES EXTRACT Hernawan Hernawan
Indonesian Journal of Chemistry Vol 8, No 1 (2008)
Publisher : Universitas Gadjah Mada

Hibiscus radiatus Cuv calyces extracts rich in polyphenols was screened for their potential to inhibit oxidation of human low-density lipoproteins-cholesterol (LDL-C) in vitro. The inhibition of LDL-C oxidation (antioxidant activity) was determined by measuring the formation of conjugated dienes and thiobarbituric acid reagent substances (TBARS). LDL-C oxidation was carried out in the presence of H. radiatus Cuv calyces extract (20 and 50 μM). CuSO4 (10 μM) was used as the oxidation initiator and butylated hydroxytoluene (BHT) at 50 μM was used as standard antioxidant. The protective effect of H. radiatus Cuv. calyces extract toward human low-density lipoproteins, complex lipid system was demonstrated by significant increase lag time (> 103 min), diminished of the propagation rate (44 %), and diminution of conjugated dienes formation 59.42 % (50 μM) compared to control.

Co-Authors A.W. Indrianingsih Bambang Purwono Cici Darsih Crescentiana Dewi Poeloengasih Khoirun Nisa M. Angwar Muhammad Kismurtono Septi Nurhayati Tutik Dwi Wahyuningsih

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