Scientia Pharmaceutica

209 KiB

Open AccessArticle

Effect of protective agents on the viability of Lactococcus lactis subjected to freeze-thawing and freeze-drying

by Diana Berner and Helmut Viernstein

Sci. Pharm. 2006, 74(3), 137-149; https://doi.org/10.3797/scipharm.2006.74.137 - 30 Sep 2006

Cited by 47 | Viewed by 2915

The effect of different protectants and the impact of the initial cell density on the viability of Lactococcus lactis Sr. 3.54 subjected to freeze-thawing and freezedrying was studied. Several additives were tested as protective agents against freezing and drying injuries. Maximum viability of [...] Read more.

The effect of different protectants and the impact of the initial cell density on the viability of Lactococcus lactis Sr. 3.54 subjected to freeze-thawing and freezedrying was studied. Several additives were tested as protective agents against freezing and drying injuries. Maximum viability of the cells after freeze-thawing was obtained with sucrose and skim milk mixtures as protective agents (78% viability). Freeze-drying with protectants based on skim milk or MRS-broth were most effective (survival levels >60%). The effect of the initial cell load on the final recovery was dependent on the protectant. Every sample showed an increase in viability when a high initial cell concentration (10¹⁰cfu ml^-1) was used. The blank showed a 1500 fold increase, skim milk/sucrose based lyophilisates an 1,7 fold increase in viability when the initial cell load was changed from 10⁰⁹ to 10¹⁰cfu ml^-1. The use of 10¹⁰cfu ml^-1 as initial cell concentration and sucrose/skim milk as protectant yielded a lyophilisate with 71% viability. Results suggest the possibility of producing freeze dried powders of Lactococcus lactis with high viability for the food industry. Full article

296 KiB

Open AccessArticle

Potentiometric Flow Injection Analysis of Bromhexine Hydrochloride and its Pharmaceutical Preparation Using Conventional and Coated Wire Ion-Selective Electrodes

by Nour T. Abdel-Ghani, Yousry M. Issa and Howayda M. Ahmed

Sci. Pharm. 2006, 74(3), 121-135; https://doi.org/10.3797/scipharm.2006.74.121 - 30 Sep 2006

Cited by 15 | Viewed by 1413

Abstract

Bromhexine hydrochloride ion-selective electrodes (conventional type) based on bromhexinium tetraphenyl borate (I) and bromhexinium-phosphotungstate (II) were prepared. The electrodes exhibited mean slopes of calibration graphs of 59.4 mV and 59.8 mV per decade of bromhexine concentration at 25°C for electrode (I) and (II), [...] Read more.

Bromhexine hydrochloride ion-selective electrodes (conventional type) based on bromhexinium tetraphenyl borate (I) and bromhexinium-phosphotungstate (II) were prepared. The electrodes exhibited mean slopes of calibration graphs of 59.4 mV and 59.8 mV per decade of bromhexine concentration at 25°C for electrode (I) and (II), respectively. Both electrodes could be used within the concentration range 3.16x10^-5-1.00x10^-2 M bromhexine within the pH range 2.0-4.5. The standard electrodes potentials were determined at different temperatures and used to calculate the isothermal coefficients of the electrodes, which were 0.00065 and 0.00050 V°C^-1 for (I) and (II), respectively. The electrodes showed a very good selectivity for bromhexine with respect to a number of inorganic cations, amino acids and sugars. The electrodes were applied to the potentiometric determination of bromhexine hydrochloride and its pharmaceutical preparation under batch and flow injection conditions. Graphite, copper and silver coated wires were prepared, characterized and successfully applied as sensors for the drug under investigation. Full article

280 KiB

Open AccessArticle

Kinetic Spectrophotometric Determination of Isoxsuprine in Dosage Forms Through Derivatisation with 4-Chloro-7- nitrobenzo-2-oxa-1,3-diazole (NBD-Cl)

by N. El-Enany, F. Belal and M. Rizk

Sci. Pharm. 2006, 74(3), 99-119; https://doi.org/10.3797/scipharm.2006.74.99 - 30 Sep 2006

Cited by 13 | Viewed by 1379

Abstract

A simple and sensitive kinetic spectrophotometric method was developed for the determination of isoxsuprine in pharmaceutical preparations. The method is based upon a kinetic investigation of the coupling reaction between isoxsuprine HCl and 4-chloro-7-nitrobenzo-2-oxa-1,3-diazole (NBD-Cl) in borate buffer of pH 7.8 for a [...] Read more.

A simple and sensitive kinetic spectrophotometric method was developed for the determination of isoxsuprine in pharmaceutical preparations. The method is based upon a kinetic investigation of the coupling reaction between isoxsuprine HCl and 4-chloro-7-nitrobenzo-2-oxa-1,3-diazole (NBD-Cl) in borate buffer of pH 7.8 for a fixed time of 30 min. The absorbance of the yellow coloured product was measured at 395 nm. The absorbance- concentration plot was rectilinear over the range of 2-20 μg mL^-1 (r= 0.9994) with minimum detectability of 0.6 μg mL^-1 (1.75 x10^-6M). The different experimental parameters affecting the development and stability of the colour were carefully studied and optimized. The determination of isoxsuprine by the fixed-concentration and rate-constant methods is also feasible with the calibration equations obtained, but the fixed time method has been found to be more applicable. The proposed method was further applied to the determination of the drug in formulations. The results obtained were in good agreement with those obtained using a reference method. The reaction pathway was proposed. Full article

331 KiB

Open AccessArticle

Ureidopyridazine Derivatives as Acyl-CoA: cholesterol acyltransferase Inhibitors

by Arianna Gelain, Ilaria Bettinelli, Daniela Barlocco, Byoung-Mog Kwon, Tae-Sook Jeong, Kyung-Ran Im, Laura Legnani and Lucio Toma

Sci. Pharm. 2006, 74(3), 85-97; https://doi.org/10.3797/scipharm.2006.74.85 - 30 Sep 2006

Cited by 3 | Viewed by 1095

Abstract

A series of N-(2,4-difluorophenyl)-N’-heptyl-N’-{4-[(substituted)-pyridazin-3-yl)thio]pentyl}urea derivatives having a phenyl ring at positions 5 and/or at position 6 of the heterocycle, as well as the corresponding sulfones, were synthesized. Their inhibitory activity against acyl-CoA:cholesterol acyltransferase (ACAT) was tested on the [...] Read more.

A series of N-(2,4-difluorophenyl)-N’-heptyl-N’-{4-[(substituted)-pyridazin-3-yl)thio]pentyl}urea derivatives having a phenyl ring at positions 5 and/or at position 6 of the heterocycle, as well as the corresponding sulfones, were synthesized. Their inhibitory activity against acyl-CoA:cholesterol acyltransferase (ACAT) was tested on the enzyme prepared from rat liver microsomes. Theoretical studies were performed to correlate their activity to their structural features. Full article

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Sci. Pharm., Volume 74, Issue 3 (September 2006) – 4 articles , Pages 85-149

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