Melt matrix materials 1 Dynasan

Dynasan 114 is a fatty acid derivative. It is the mono-acidic triglyceride o f myristic acid known as myristic-acid triglyceride. It is commercially available in powder form and used in the food and pharmaceutical industry. In pharmaceuticals, it serves as a carrier in parenteral dmg forms, as a retarding agent and in rectal and vaginal preparations as a crystallization accelerator. It is also used as consistency regulator and powder base in its microcrystalline form. In the food industry it serves as an auxiliary in the production of compressed sweets. It appears as a white to cream coloured wax-like solid with a light powder consistency. Its analytical parameters are as follows: acid value maximal 3 mg KOH/g, iodine value maximal Ig I2/IOO g,

saponification value maximal 229 mg to 238 mg KOH/g and hydroxyl value maximal 10 mg KOH/g. Its melting range is between 55 ”C and 58 °C (Product Info CONDEA,

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Hüls). The material was supplied by Sasol Chemicals mbH (formerly Hüls group), Witten, Germany, and the batch numbers were 701 142 and 105 151.

1.2.2 Further materials screened

During an exploratory procedure a further number of commercially available products were screened for their suitability as melt matrix materials. Their trade names, batch details and manufacturers are listed in Table 2.1.

T a b le 2 .1: M a te r ia ls sc r e e n e d .

Trade name Batch details Manufacturer

Methocel E4MCR - Premium EP

MM87021111E Colorcon, Ltd., Orpington, England HPMCP H50

HPMCP H55C HPMCP HP55

708229 811442

Colorcon, Ltd., Orpington, England

Methocel KlOO M - Premium USP

MM90031202K Colorcon, Ltd., Orpington, England Ethylcellulose N-10

Ethylcellulose-100

57836 BG9708

Glaxo, Ware, England

Dimetylphthalate 6049811 Eastman Chemical Co., Kingsport, USA AQOAT AS-LF AQOAT AS-MF AQOAT AS-HF 701002 804018 606065

Shin Etsu Chemical Co., Ltd., Niigata, Japan Eudragit RL 100 EudragitRS 100 Eudragit RS PC Eudragit L 100 0490916137 8381008148 0490638102 0490703116

Rohm GmbH Chemische Fabrik, Darmstadt, Germany

Imwitor 900 - NF type 1

608233 Sasol Chemicals GmbH (formerly Hüls group), Witten, Germany

Sterotex (HSBC) 14598A Abitec, Corp., Janesville, Wl, USA Soflisan 142

Softisan 154 609041

Sasol Chemicals GmbH (formerly Hüls group), Witten, Germany

Dynasan 116 303014 Sasol Chemicals GmbH (formerly Hüls group), Witten, Germany

QMS (250 pm) 209215 Sasol Chemicals GmbH (formerly Hüls group), Witten, Germany

PEG 3000S 106315564 Hoechst, AG, Frankfurt/M., Germany Witepsol W45 608733 Sasol Chemicals GmbH (formerly Hüls

group), Witten, Germany Magnesium stearate 1324530 Merck, Poole, England

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1.3 Enzymes

For all a-amylases mentioned below, one unit is defined as the amount of enzyme liberating 1.0 mg of maltose from starch in 3 min at pH 6.9 at 20 °C.

1.3.1 B.licheniformis-oi~amy\ase

The a-amylase used is a bacterial enzyme isolated from Bacillus licheniformis, which is involved in the decomposition of green plant matter. It is supplied as an aqueous suspension containing approximately 15 % sodium chloride and 25 % sucrose. Its activity has been determined using the Biuret-method as 30 mg protein/ml or 870 units/mg protein (Product Info Sigma-Aldrich). The suspension, which contains a large amount of cell debris visible as sediment, has a dark brown colour and gives off a strong odour typical for hay and fermented straw. It has to be stored at 4 °C in an airtight brown bottle in order to prevent enzyme degradation due to oxidation and light. The enzyme in this work was designated Type XII-A and supplied by Sigma Chemicals Co. (St. Louis, MO, USA) as a 200-ml solution in sodium chloride with an activity of 25000 U/ml. The batch number was 67H1563 and the EC-number was 232-560-9.

1.3.2 Human-saliva-a-amylase

This a-amylase is obtained from human saliva by means o f purification using a Sephadex chromatography column. The a-amylase fraction is then collected and further purified by crystallization. The final product can be described as needle- shaped crystallites with a yellowish colour. It is odourless in its dry form but develops a characteristic pleasant odour when in solution. It is hygroscopic and has to be stored at below -18 °C. The enzyme used was supplied by Fluka, BioChemika, Fluka Chemie GmbH (Buchs, Switzerland) as 25 mg crystallites with an activity of 96.7 U/mg and the molecular weight was 69000 Da according to the literature. The batch number was 347647/1 45000 and the EC-number was 2325656.

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1.3.3 Hog-pancreas-a-amylase

Hog-pancreas-a-amylase is a typical endo-amylase that catalyses the hydrolysis of starch, glycogen and related polysaccarides by random, multiple attack hydrolysis of a-D-(l,4) glucan linkages.

The material is commercially available as a twice-crystallised product free of other proteins naturally present in hog pancreas. The material is a light powder with an off- white colour and a characteristic sweet yet unpleasant odour. It has to be stored at 4 °C. It is moderately soluble in aqueous medium, where it tends to aggregate into small filamentous clusters if left unstirred. This enzyme was supplied by Fluka, BioChemika, Fluka Chemie GmbH (Buchs, Switzerland) as 25 g powder with an activity of 57 U/mg and a molecular weight of 50000 according to the literature. The batch number was 10925/1 14101 and the EC-number was 2325656.

1.3.4 B.amyloliquefaciens-a-amylase

This a-amylase was obtained from Bacillus amyloliquefaciens, which is naturally present in the human intestinal system. It is an exogenic enzyme and thus can be extracted from the culture medium of the bacteria. The enzyme was lyophilised and contained less than 0.1 % of protease as the only foreign protein activity. It appears as an off-white crystalline powder, which is odourless and moderately hygroscopic. It has to be kept at 4 ®C and protected from light. The enzyme was supplied by Fluka, BioChemika, Fluka Chemie GmbH (Buchs, Switzerland) as 100 mg powder with an activity of 1546 U/mg and a molecular weight of 50000 according to the literature. The batch number was 420456/1 52601 and the EC-number was 2325609.

1.3.5 Pancreatin

Pancreatin is an enzyme mixture containing principally amylase, lipase and protease obtained from the pancreas of the hog or of the ox. It contains in each milligramm not less than 25 units of amylase activity, not less than 2 units of lipase activity and not less than 25 units of protease activity (USP 24, 2000). The enzyme mixture is obtained from the stomach mucosa and subsequently lyophilised. It exists

Chapter 2

as a white odourless powder and is easily dissolvable in aqueous medium. It has to be stored below 0 ®C in the absence of light. Its activity is at least equivalent to the USP specification given by the supplier.

Pancreatic lipase hydrolyses the water-insoluble triacylglycerols in the intestinal lumen and thereby plays an important role in dietary fat absorption. It is very similar to that of human pancrease lipase as both display the same molecular weight of approximately 50 kDa, the same composition of amino acids and a similar reactivity in the sulphide groups (Borgstrom, 1975). But the enzyme has also been isolated from a number o f mammalian species, such as pig, rat, dog and mouse. These, too, show clear homology amongst them. Triglyceride hydrolysis is inhibited by physiological concentrations of bile salts and a major conformational change occurs upon activation o f the enzyme at the enzyme-substrate interface. The enzyme was supplied by Sigma Chemical Co. (St. Louis, MO, USA) as 100 g powder. The batch number was 21K/230 and the EC-number was 232-468-9.