• Analytical Science and Technology
• /
• v.23 no.4
• /
• pp.389-394
• /
• 2010

An ICP-AES method for determination of calcium content and dissolution characteristics of oyster shell (Ostrea gigas) has been developed and validated. Total calcium content in oyster shell was determined using ICPAES. The dissolution characteristics, which would reflect the composition of $CaCO_3$ polymorphs and calcium salts in oyster shell, were also evaluated by dissolution test. The total calcium contents ranged from 31.8 to 39.9% and the dissolution ratios varied from 62.7 to 83.6% (n=15). The determination of calcium content and dissolution characteristics by ICP-AES would provide useful information for the quality control of oyster shell.

• Journal of Pharmaceutical Investigation
• /
• v.14 no.1
• /
• pp.1-10
• /
• 1984

Effects of water soluble carrier on the dissolution characteristics of indomethacin coprecipitates were investigated. Water soluble carriers used were polyvinylpyrrolidone, dextrose, mannitol and their mixtures of various ratios. The dissolution rates of indomethacin from coprecipitate with ratios of drug-to-carrier, kinds of carrier and ratios of carriers were as follows: 1. The dissolution rates increased proportionally to the ratios of carrier in the case of both single and combined carrier, and the dissolution rate of coprecipitate with the combined carrier was more rapid than that with single carrier. 2. The combined carrier of PVP-dextrose (1 : 2) in the case of the coprecipitate of drug-to carrier (1 : 1) and PVP-dextrose (4 : 1) in the case of the coprecipitate of drug-to carrier (1 : 3) yield the most rapid dissolution rate. 3. The dissolution rate of indomethacin was the most markedly enhanced in the case of the combined carrier of PVP and dextrose.

• Journal of the Korean Ceramic Society
• /
• v.32 no.10
• /
• pp.1093-1102
• /
• 1995

Water-soluble phosphate glasses containing Ag or Cu ion were prepared through melting process. Then the powdered glass samples were dissolved in D.I. water at room temperature with changing the dissolution time. In terms with the glass composition, dissolution characteristics, bactericidal effects and cytotoxicities were investigated. Dissolved amounts increased uniformly with dissolution time, and the dissolution rate was higher for ternary glass than for binary glass and with less metal oxide amount. And the dissolution rate of the glass with Ag ion was higher than that with Cu ion, and the bactericidal effect of the glass with Ag ion was also greater. Solution with more than 25 ppm of Ag was observed to have strong cytotoxicity to L929, and solutions of lower Ag concentration or with Cu seemed to have little cytotoxicity.

• Archives of Pharmacal Research
• /
• v.18 no.5
• /
• pp.314-319
• /
• 1995

Antacid granules were prepared by agglomeration and powder method in high speed agitation type granulator. The copmositions of the test antacids were sodium bicarbonate nad magnesium carbonate nad a coating material was powder of polyvinylacetal diethyl-aminocacetate (AEA) and an additive material was talc powder. The dissolution characteristics of base from the antacid granules were investigated to evaluate neutralization capacity of hydrochloric profile of base and neutralization behavior, the following results were obtained : The prepared granules showed a pH-dependent dissolution pattern of a base. The dissolution profile of a base was varied with addition of talc powder as well as coating amount of AEA. The relationship between the ratio of dissolution retarded time for 20% and 10% AEA. The relationship between the ratio of dissolution retarded time for 20% AEA coated granules $\theta_{20}/\theta_{10}$ and the diameter reduction of the granules was explained by the rate process of neutralization of hydrochloric acid.

• Journal of the Korean Ceramic Society
• /
• v.34 no.1
• /
• pp.13-22
• /
• 1997

Water-soluble phosphate glasses containing Ag and Cu ion were prepared through melting process. Dis-solution characteristics, bactericidal effect and cytotoxicity were investigated with composition and time in D. I. water using the powdered sample. Surface change were observed with increasing dissolution time us-ing the bulk specimen. Dissolution amount was maximum at the molar Ag:Cu ratio of 1 and increased with increasing time. The behavior of dissolution was total dissolution from the early stage. But no new layer was observed at the glass surface during dissolution. The bactericidal effect for pseudomonas sp, e. coli, sta-phylococcus aureus, and salmonella increased with increasing dissolution amount and therefore great bac-tericidal effect appeared. The result of cytotoxicity experiment to L929 showed that solution with more than 10 ppm of Ag ion had strong cytotoxicity.

• Journal of Pharmaceutical Investigation
• /
• v.6 no.3
• /
• pp.48-57
• /
• 1976

An enhancement in the dissolution rate of the drug should facilitate its GI absorption if the absorption process is dissolution rate limited. One of the need for the techniques that can potentially enhance the dissolution rate and extent of absorption of hydrophobic drugs is the formation of coprecipitates with pharmacologically inert, polymeric materials. The physicochemical modification offers the advantage of possibly enabling one to administer the drug orally in a form from which it is most available for GI absorption. Several $investigation^{1-15)}$ demonstrated that the formation of solid dispersions or coprecipitates of relatively water-insoluble drugs with various pharmacologically inert carriers can increase singnificantly their in vitro dissolution rates. However, little information is available in the literature related to the dissolution rate patterns of furosemide, a water-insoluble diurectices, with respect to the sort of copolymer and the ratio of coprecipitates as a function of time, respectively. The purpose of the present investigation was to ascertain, the general applicability of the copolymers to use fore more fast, enhanced dissolution techniques of furosemide. To accomplish the need for enhancement in the dissolution rate of furosemide, varying ratio coprecipitates with different water-soluble polymers, such as polyvinylpyrrolidone (PVP), polyethylene glycol 4000(PEG 4000), and polyethylene glycol 6000 (PEG 6000), were quantitatively studied by comparing their dissolution characteristics of furosemide. The dissolution patterns of pure furosemide, varying ratio furosemide-PVP coprecipitates, (1:2, 1:5, and 1:9(w/w)), furosemide-PEG 4000 coprecipitates (1:4, 1:9, and 1:19(w/w), furosemide-PEG 6000 coprecipitates(1:4, 1:9, and 1:19(w/w)), and the same ratio physical mixtures, respectively, were compared by the amount dissolved as a function of time.

• Archives of Pharmacal Research
• /
• v.2 no.1
• /
• pp.35-47
• /
• 1979

In order to increase the dissolution rate of furosemide(4-choro-N-furfury1-5-sulfamoy1 anthranilic acid_, various ratio coprecipitates with water-soluble polymers, such as polyvinylpyrrolidone and polythylene glycol, of different molecular weight, were prepared and quantitatively studied by comparing their dissolution characteristics of furosemide at powder state and at nondisintegrating disk state containing constant surface area at various temperatures and rotating velocities. The dissolution characteristics of furosemide from pure furosemide disks and 1:2(w/w) furosemide-PVP coprecipitate disks were in accordance with Noyes-Nernst equation and the rate constant of dissolution was proportional to the square root of rotating velocity of the disks. The intrinsic rate of dissoluton at 150 rpm, 37.deg.C was $2.21{\times}10^{-7}$ for the PVP 10, 000 COPRECIPITATE, $1.64{\times}10^{-7}$ for the PVP 40, 000 coprecipitate, and$ 1.44 {\times} 10^{-7}$for the PVP 360, 000 corprecipitate, while the rate was $1.27{\times}10^{-8}M/cm^{2} min$ for pure furosemide, repectively. The activation energy of dissolution was about 17, 000 for furosemide and about 7, 300 cal/mole for the 1:2 furosemide PVP 40, 000 coprecipitate, respectively.

• Journal of Korea Technical Association of The Pulp and Paper Industry
• /
• v.47 no.6
• /
• pp.89-97
• /
• 2015

In this study, dissolution characteristics of 60% LiBr aqueous solution for Miscanthus sinensis holocellulose in accordance with heating time and characteristics of regenerated films were analyzed. Miscanthus sinensis holocellulose was made by peracetic acid method. During the dissolution of 60% LiBr solution for the holocellulose, the dissolution was started from the tip of the cellulose fiber after about 7 minutes, and proceeded as it swollen like a balloon. A lot of Si was identified by analyzing hollocellulose regenerated film through SEM/EDS. Cross section of regenerated film as dissolution time till 40 minutes of dissolution showed multilayered structure and fiber orientation. But after 40 minutes, multilayered structure and fiber orientation was not observed. The crystal structure of the holecellulose was transformed cellulose I into cellulose II. Therefore, dissolution for 20 minutes with 60% LiBr solution in the condition of $190^{\circ}C$ hot plate was shown as an optimum condition to manufacture the holocellulose regenerated film.

• Journal of Pharmaceutical Investigation
• /
• v.36 no.3
• /
• pp.161-167
• /
• 2006

The objective of this study was to investigate the dissolution patterns of variety of orally administered drug products available on the market. It aimed to understand their dissolution behaviors on the basis of the biopharmaceutics classification system (BCS) concept. On the tenets of BCS, several active pharmaceutical ingredients were selected: fluoxetine hydrochloride (class I), naproxen sodium (class ll), pyridostigmine bromide (class III), furosemide (class IV) and simvastatin (class IV). Typical dissolution media used in this study were pH 1.2, pH 4 & 6.8 phosphate buffers, and water. In cases, particular dissolution media specified in the KP and/or USP were used. Dissolution patterns of fluoxetine hydrochloride and pyridostigmine bromide products were characterized by their rapid release In addition, their dissolution characteristics were relatively unaffected by the type of a dissolution medium. Similar dissolution patterns were observed with pH 1.2, pH 4 & 6.8 phosphate buffers and water. By sharp contrast, poor dissolution patterns were noticed with naproxen sodium products, when pH 1.2 and pH 4 phosphate buffer were used. Improvements in its dissolution were achieved by switching the dissolution media to pH 6.8 phosphate buffer or water. Unsatisfactory dissolution data also were observed with a simvastatin product, when it was subject to dissolution tests by use of a surfactant-free pH 1.2, pH 4 & 6.8 phosphate buffers and water. All the release patterns reported in this study were best understood when BCS concepts were implemented. Our results demonstrated that a BCS-based drug classification should be considered first to choose a dissolution test/method and set up dissolution specification.

• Proceedings of the PSK Conference
• /
• 2003.10b
• /
• pp.228.1-228.1
• /
• 2003

Purpose. The purpose of this study is to compare in vitro dissolution characteristics and bioavailability in beagle dog of a hard gelatine capsule containing erdosteine (Yuhan Erdosteine capsule$\^$TM/) with those of commercial product (Erdos capsule$\^$TM/). Methods. Yuhan Erdosteine capsule$\^$TM/ was prepared using erdosteine 300 mg, lactose, magnesium stearate, and others by powder filling method. The dissolution characteristics of Yuhan Erdosteine capsule$\^$TM/ and Erdos capsule$\^$TM/ were determined by USP dissolution apparatus 2. (omitted)