Method of producing a swellable polymer fibre

Abstract

A swellable polymer based fiber and a method of preparing the same optionally comprising glycol, lecithin and optionally an antimicrobial metal species suitable, for example, for medical applications including wound dressings. A method of manufacture may comprise fiber extrusion or spinning involving one or a plurality of in-series coagulation baths to add single or multiple antimicrobial metal species to the as-formed fiber.

Claims

1. A method of forming a swellable polymer based fibre comprising: creating an aqueous dope solution containing a water soluble polymer; spinning or extruding the dope solution into a coagulation bath to form an extruded fibre; drawing the fibre from the coagulation bath; adding a glycol to the dope solution, the glycol having between two to fifteen carbon atoms; and adding a lecithin to the dope solution.

2. The method as claimed in claim 1 further comprising adding a metal based antimicrobial agent to the dope solution.

3. The method as claimed in claim 2 wherein the antimicrobial agent comprises silver, a silver ion or a silver substrate.

4. The method as claimed in claim 1 further comprising adding a metal based antimicrobial agent to the coagulation bath.

5. The method as claimed in claim 4 wherein the antimicrobial agent is a metal ion selected from any one or a combination of the following set of: Zn, Cu, Ti, Pt, Pd, Bi, Sn, Sb.

6. The method as claimed in claim 1 wherein the polymer comprises any one or a combination of a polysaccharide or a hydrocolloid forming polymer and optionally pectin, alginate, psyllium, carboxymethylcellulose, konjac, aloe vera and/or chitosan.

7. The method as claimed in claim 1 wherein the glycol comprises between two to fifteen carbon atoms.

8. The method as claimed in claim 1 wherein the glycol is added at a concentration of 0.05 to 10% by weight of the dope solution.

9. The method as claimed in claim 1 further comprising adding any one or a combination of the following to the dope solution: psyllium carboxymethylcellulose high mannuronate content alginate high guluronate content alginate.

10. The method as claimed in claim 1 wherein the lecithin is added at a concentration of 0.05 to 10% by weight of the dope solution.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) A specific implementation of the present invention will now be described, by way of example only, and with reference to the accompanying drawings in which:

(2) FIG. 1 shows a cross-sectional view of apparatus used in wet spinning a swellable polymer fibre with a single coagulation bath according to a specific implementation of the present invention;

(3) FIG. 2 shows a cross-sectional view of apparatus used in wet spinning a swellable polymer fibre using two coagulation baths coupled in-series according to a further specific implementation of the present invention;

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT OF THE INVENTION

(4) Referring to FIG. 1, swellable polymer fibres are produced by first dissolving a polymer species in water to form a dope solution 102. The dope solution is contained within a vessel 101 under an inert atmosphere. The dope solution 102 is then passed directly through a pump 103 which increases the pressure of the system. The dope solution 102 is then filtered by a filter 104, before entering a spinneret head 105. The spinneret head 105 is immersed in the coagulant 107 contained within a coagulation bath 106. Dope solution 102 is then extruded into coagulation bath 106 to form fibre filaments 108 which are then hauled-off over filament guides 109 and 110 from bath 106 by means of first advancing rollers 111. The resulting fibres 112 are then passed through orientation bath 113 containing hot water whilst being drawn by second advancing rollers 114 within a wash bath 115 to form a resulting fibre 116.

(5) As a modification to the apparatus and method of FIG. 1, according to a further embodiment shown in FIG. 2, the swellable polymer fibres are passed through a second coagulation bath 118 after passing between a set of three guide rollers 117 to remove tow excessive coagulant from bath 106. The fibres are slightly stretched as they pass between the first coagulation bath 106 and enter second coagulation bath 118 via means 111. The resulting fibres 119 are then passed through orientation bath 113 containing hot water and then further drawn by means 114 within wash bath 115 to form the resulting fibre 120.

EXPERIMENTAL

(6) Within the following examples 1 to 13, the amount of solid added to the dope is expressed as a weight percentage of the weight of the dope.

Example 1

(7) Calcium alginate polymer fibres containing 1,2-propanediol were produced using the method described with reference to FIG. 1. A 1500 g dope solution was prepared using 5% (w/w) High G sodium alginate (Protanal LF 10/60 FT) and 10% (w/w) propylene glycol, PG (supplied by Sigma-Aldrich, by 187 C. density 1.036 g/cm.sup.3) The alginate used was supplied by FMC Biopolymer (UK) Ltd) and had the following characteristics: guluronic acid content 60-70%; mannuronic acid content 30-40%; G/M ratio 1.5-2.33, viscosity (1%) 30-60 cps, moisture <15% and pH 6-8. The required amount of the alginate powder (75 g) was first dissolved in 1275 g of water for 30 minutes using a Greaves high shear mixer. Then, 150 g of PG was slowly added and further stirred for 30 minutes or until fully mixed and homogeneous dope. (viscosity 8,000-10,000 cps at 26 C. using Brookfield Digital viscometer (RVTD), spindle No. 04). The solution was slowly fully vacuum de-aerated, spun through a cartridge filter (25-microns) and spinneret (70 hole size/2000 holes) into 1.5-2% aqueous calcium chloride dihydrate. After coagulation, the fibres were stretched and washed to give strong propylene glycol-calcium alginate fibres.

Example 2

(8) Calcium alginate and psyllium polymer fibres containing 1,2-propanediol were produced using the method described with reference to FIG. 1.

(9) A spinning solution (6,000 g) was prepared comprising 240 g (4% w/w) High M sodium alginate, 45 g (0.75% w/w) psyllium husks (Plantago ovate, supplied by W. Ratje Froeskaller ApS Husk Products, Kirstinehoej 34, DK-2770 Kastrup, Denmark) and 120 g (2% w/w) PG. The high M alginate (Manucol DH) was supplied by FMC Biopolymer (UK) Ltd) and had the following characteristics: mannuronic acid content 60-70%; guluronic acid content 30-40%; G/M ratio 0.43-0.67, viscosity (1%) 40-90 cps, moisture <13% and pH (1% solution) 5.0-7.5.

(10) First, the psyllium was soaked in about 5,600 g of water for 1 hour at room temperature and at the end filtered through a Philips blender cartridge filter. The filtered aqueous psyllium solution was then stirred vigorously using a high shear mixer whilst gradually adding the alginate powder. The alginate was allowed to dissolve well (30-45 minutes) before gradually adding PG and further mixing (20-30 minutes) to obtain a homogeneous dope (viscosity 8,000-15,000 cps at 26 C.). The dope was spun after vacuum deaeration and filtration through a spinneret (70/2000 holes) into 1.5-2% aqueous calcium chloride dihydrate. After coagulation, the fibres were stretched and washed to give strong absorbent calcium alginate/PG/psyllium fibres.

Example 3

(11) Calcium alginate and psyllium polymer fibres containing 1,2-propanediol and antimicrobial silver ions were prepared using the method described with reference to FIG. 1.

(12) Example 2 was repeated except that the dope contained 3 g (0.05% w/w) silver carbonate. The silver carbonate can be dispersed in water by sonicating for 1 hour in ultrasonic bath before mixing into the filtered psyllium solution. However, in this example, the carbonate was dispersed in PG, sonicated briefly (10 minutes) before adding to the dope. After deaeration and filtration, the dope was spun through a 90/2000-hole spinneret.

Example 4

(13) Calcium alginate and carboxymethylcellulose (CMC) polymer fibres containing 1,2-propanediol and antimicrobial silver ions were produced using the method described with reference to FIG. 1.

(14) The process corresponded to examples 3 and 4 except that the dope contained 30 g (0.5% w/w) of CMC instead of psyllium. The GPA grade CMC powder (degree of substitution 0.82-0.95; pH 6.5-8.5 and supplied by Dow Wolff Cellulosics GmbH) was mixed with the 240 g sodium alginate powder before dissolving in 5607 g of water.

Example 5

(15) Calcium alginate and pectin polymer fibres containing 1,2-propanediol and antimicrobial silver ions were produced using the method described with reference to FIG. 1.

(16) The process involved the same components and steps as Example 4 but using pectin instead of CMC.

Example 6

(17) Alginate polymer fibres containing antimicrobial silver, copper and zinc ions were produced following using the method described with reference to FIG. 2.

(18) This example describes the production of antimicrobial alginate fibres containing 6% Cu, 4-5% Zn and 0.6% Ag. Initially, 500 g dope was prepared by mixing together 20 g (4% w/w) High G sodium alginate (Protanal LF 10/60 FT supplied by FMC Biopolymer (UK) Ltd) and 0.25 g (0.05% w/w) each of silver nitrate, copper chloride and zinc chloride in 479.25 g water. The alginate supplied had the following characteristics: guluronic acid content 60-70%; mannuronic acid content 30-40%; G/M ratio 1.5-2.33, viscosity (1%) 30-60 cps, moisture <15% and pH 6-8.

(19) However, the dope prepared from this combination was brittle, viscous, light green in appearance and considerably difficult to extrude due to filtration problems. Further attempts were made with varying proportions of the salts in the dope but not much success was achieved with extrusion. However, when the same weight of dope was prepared with only silver nitrate or silver carbonate and spun through 90/2000-hole spinneret into successive baths containing respectively aqueous solutions of 0.5% copper chloride dihydrate and 1.5% zinc chloride, no difficulties were experienced, thus establishing the best practical approach to incorporate all the three metal ions into the fibres.

(20) After coagulation, the fibres were stretched and washed to give strong silver alginate fibres containing copper and zinc, with the amounts of the metals ions in the fibre depending almost entirely on the coagulant concentrations. Consequently, it was necessary during extrusion to ensure consistent concentrations of the salts in their respective coagulation baths through reduction of coagulant cross contamination and mass balancing

Example 7

(21) Alginate polymer fibres containing 1,2-propanediol and antimicrobial silver, copper and zinc ions were produced using the method described with reference to FIG. 2.

(22) This example describes the production of antimicrobial propylene glycol alginate fibres containing 8-9% Zn, 0.5-1% Cu and 0.5% Ag. A 1500 g dope solution was prepared using 75 g (5% w/w) High G sodium alginate (Protanal LF 10/60 FT), 150 g (10% w/w) propylene glycol, PG (supplied by Sigma-Aldrich, by 187 C. density 1.036 g/cm.sup.3) and 3 g (0.05% w/w) silver carbonate. The required amount of the alginate powder was first dissolved in 1275 g of water for 30 minutes using a high shear mixer. The silver carbonate powder was dispersed in PG by sonicating briefly (10 minutes) in an ultrasonic bath before adding slowly to the dope whilst stirring vigorously. After the addition, the dope was mixed for a further 45 minutes, then vacuum de-aerated and filtered under pressure through a 25 cartridge filter before extruding through a 90/2000-hole spinneret into two successive coagulations bathsthe first bath containing 1.5% zinc chloride and the second bath 0.05-0.15% copper chloride. After coagulation, the fibres were stretched and washed to give strong zinc alginate fibres containing copper and silver.

Example 8

(23) Alginate and psyllium polymer fibres containing 1,2-propanediol and antimicrobial silver, copper and zinc ions were produced using the method described with reference to FIG. 2.

(24) This example describes the production of fibres containing 5% Zn, 6% Cu and 0.5% Ag. Example 6 was repeated except that the dope also contained about 11.25 g (0.75% w/w) psyllium husk (Plantago ovate, supplied by W. Ratje Froeskaller ApS Husk Products, Kirstinehoej 34, DK-2770 Kastrup, Denmark) and a reduced amount of sodium alginate, 60 g (4% w/w) and PG, 30 g (2% w/w). The 11.25 g psyllium were soaked in 1415 g water for 1 hour at room temperature and at the end filtered through a Philips blender cartridge filter. The filtered aqueous psyllium solution was then stirred vigorously using a high shear mixer whilst gradually adding the alginate powder. The alginate was allowed to dissolve well (30-45 minutes) before gradually adding PG containing 3 g (0.05%) silver carbonate which had been previously dispersed in the glycol by sonicating in ultra-sonic bath. The components were continuously mixed until a homogeneous dope was obtained (1 hour). After deaeration and filtration, the dope was spun through a spinneret (70/2000 holes) into two successive coagulations bathsthe first bath containing 1.5% zinc sulphate and the second bath 0.5% copper chloride. After coagulation, the fibres were stretched and washed to give strong zinc alginate/psyllium/PG fibres containing copper and silver.

Example 9

(25) Alginate and CMC polymer fibres containing 1,2-propanediol and antimicrobial silver, copper and zinc ions were produced using the method described with reference to FIG. 2.

(26) Example 7 was repeated except that the dope contained 15 g (1.0% w/w) of CMC mixed with alginate powder before dissolution.

Example 10

(27) Calcium alginate polymer fibres containing 1,2-propanediol and lecithin were produced following the method described with reference to FIG. 1.

(28) A dope (1000 g) was prepared using 4% (w/w) High M sodium alginate (Manucol DH supplied by FMC Biopolymers, UK, Ltd), 10% (w/w) propylene glycol, PG (supplied by Sigma-Aldrich) and 0.05% granular L-alpha-lecithin (supplierAcross Organics). The required amount of the alginate powder (75 g) was mixed with 0.5 g of lecithin and dissolved in about 900 g of water for 45 minutes using a high shear mixer. Then, 100 g of PG was slowly added and further stirred for 30 minutes or until fully mixed and a homogeneous dope was formed (viscosity 8,000-10,000 cps at 26 C. using Brookfield Digital viscometer (RVTD), spindle No. 04). The solution was slowly fully vacuum de-aerated, spun through a cartridge filter (25-microns) and spinneret (90 hole size/35 holes) into 1.5% aqueous calcium chloride dihydrate solution. After coagulation, the fibres were stretched and washed to give strong propylene glycol-lecithin alginate fibres.

Example 11

(29) Calcium alginate and psyllium polymer fibres containing 1,2-propanediol and lecithin were produced following the method described with reference to FIG. 1.

(30) A spinning solution (6000 g) was prepared by first soaking 60 g (0.5%) of psyllium husks in 5394 g of water for 2 hours and filtering the mixture through a 75-micron mesh. This was followed by mixing sodium alginate powder (Protanal LF 10/60 FT), 240 g (4% w/w) with 6 g (0.5% w/w) of granular L-alpha-lecithin. The filtered aqueous psyllium solution was then stirred vigorously using a high shear mixer whilst gradually adding the mixed powders. Stirring was continued for 30 minutes before gently adding 300 g (5% w/w) PG and further mixing (30 minutes) to obtain a homogeneous dope (viscosity 10,000-15,000 cps at 26 C.) suitable for extrusion. The dope was spun after vacuum deaeration and filtration through a spinneret (70/2000 holes) into 1.5-2% aqueous calcium chloride dihydrate. After coagulation, the fibres were stretched and washed to give strong absorbent fibres.

Example 12

(31) Alginate and psyllium polymer fibres containing 1,2-propanediol, lecithin and antimicrobial silver ions were produced using the method described with reference to FIG. 1.

(32) Example 11 was repeated except that the dope contained 3 g (0.05% w/w) silver carbonate; the silver carbonate being dispersed in PG before adding.

Example 13

(33) Alginate, CMC and psyllium polymer fibres containing 1,2-propanediol, lecithin and antimicrobial silver, copper and zinc metal ions were produced following the method described with reference to FIG. 2.

(34) A dope (6000 g) contained 240 g (4% w/w) of sodium alginate, 30 g (0.5% w/w) of CMC, 3 g (0.05% w/w) of lecithin, 36 g (0.6% w/w) of psyllium, 120 g (2% w/w) of propylene glycol and silver carbonate (3 g, 0.5% w/w). First, the psyllium was soaked for 1 hour in 5568 g of water and filtered at the end through a 75-micron mesh. The sodium alginate, CMC and lecithin powders were mixed together and gradually added to the psyllium solution stirred vigorously by a high shear mixer. The powders were allowed to dissolve well (45 minutes) before gradually adding PG containing properly dispersed silver carbonate. The components were continuously mixed until a homogeneous dope was obtained (45 minutes). After deaeration and filtration, the dope was spun through a spinneret (70/2000 holes) into two successive coagulations bathsthe first bath containing 1.5% zinc sulphate and the second bath 0.5% copper chloride. After coagulation, the fibres were stretched, washed and dried to give good absorbent fibres suitable for wound dressing.

Examples 14 to 20

(35) Highly swellable fibres with varying integrities were prepared using the component concentrations detailed below in examples 14 to 20. In each example, a dope of 2500 g with a solid content of 5% w/w was prepared. In examples 14 to 20, the amount of solid added to the dope is expressed as a percentage by weight of the total amount of solid added to the dope solution where the total amount of solid added was 5% by weight. The solids according to examples 14 to 20 include any one of alginate, HM-alginate, HG-alginate, psyllium, CMC, lecithin. Referring to example 14 below, the HM alginate was dispersed in 10% propylene glycol (PG), stored for 1 hour and then added to the water used to prepare the dope. No lecithin, psyllium, HG-alginate or CMC was added. The relative amount of the components of example 14 include: a dope weight 2500 g; dope concentration 5%; HM-alginate 125 g; PG 250 g and water (85%) 2125 g.

(36) However, for the remaining examples 15 to 20, all solids (where appropriate) were first prepared prior to introduction to the dope by dispersion within propylene glycol (PG) with the glycol/solids dispersion allowed to stand for at least one hour before mixing into the aqueous dope and stirring 45 minutes to one hour until a homogenous dope was obtained. The concentrations of examples 14 to 20 are shown in table 1.

(37) TABLE-US-00001 TABLE 1 compositions of examples 14 to 20 Percentage in 5% % Dope solid content PG viscos- Exam- P/HM/ in ity ple Composition HG LE CMC dope cP 14 AF-PG-140703-HM 0/100/0 10 18,920 15 *AF-140704-PG-HM 0/100/0 10 14,840 16 AF-PG-LE-140714- 0/99.4/ 0.6 5 12,160 HM 0 17 AF-CMC-PG-LE- 0/79.4/ 0.6 20 5 10,480 140804-HM 0 18 AF-CMC-PG-LE- 0/45/30 0.6 24.4 5 10,680 140806-HM/HG 19 PF-CMC-PG-LE- 13.4/41/ 0.6 25 5 13,440 140807-HM/HG 20 20 PF-CMC-PG-LE- 14.4/50/ 0.6 25 5 11,880 140812-HM/HG 10 AFAlginate fibre without psyllium; PFalginate fibre with psyllium; Ppsyllium; HMHigh M Na-alginate (Manucol DH); HGHigh G Na-alginate (Protanal LF 10/60FT) *Alginate dissolved before addition of PG
Performance Testing

(38) The viscosity of the dope solution was measured using a Brookfield digital viscometer (RVTD) and RV spindle size 04 at 25 C. Selected fibres from the examples cited were tested as follows:

(39) Liquid Absorption Properties of the Fibre Samples

(40) The liquid absorption properties of the fibres prepared were assessed in saline (9 g, 0.9% w/v NaCl in 1 liter de-ionized water) and in solution A (mixed CaCl.sub.2.2H.sub.2O and NaCl solution containing 142 mmol/liter Na.sup.+ ions, 8.298 g NaCl and 2.5 mmol/liter of Ca.sup.2+ ions, 0.368 g CaCl.sub.2.2H.sub.2O).

(41) a) Absorbency

(42) Absorbency was determined by fully immersing 1.0 g fibre sample in 100 g saline or solution A contained in a Petri dish and allowing to stand for 301 min in oven at 37 C. The sample was removed, then allowed to drain for 30 seconds and weighed. Absorbent capacity (g/g) was calculated as the ratio of the wet weight (W.sub.1) of the fibre to the dry weight (W.sub.0) at ambient temperature.

(43) b) Liquid Uptake (Retention)

(44) Liquid uptake is expressed as (W.sub.1W.sub.2)/W.sub.2 and was determined as follows: The wet weight (W.sub.1) is the weight after a 1.0 g sample has been immersed in 100 g of deionised water or saline or solution A for at least 30 minutes in an oven at 37 C., then removed and allowed to drain for 30 seconds. The dry weight (W.sub.2) is the weight after the wet sample (centrifuged at 1500 rpm for 15 min) has been dried in an oven for at least 4 hr at 105 C. From these weights the water, saline or solution A uptake (retention) was calculated.

(45) Silver Content of Fibres and Competitive Wound Dressings (at Intertek ASG)

(46) Duplicate 0.5 g quantities of each sample were placed in a quartz microwave digestion vessel and digested with nitric and sulphuric acid. After digestion samples were transferred to 50 ml volumetric flasks and made up to volume with deionized water. Sample solutions were analysed by ICP-OES for silver.

(47) Silver Release from Fibres and Competitive Wound Dressings (at Intertek ASG)

(48) Samples were weighed into separate 50 ml plastic centrifuge tubes and a 25 ml aliquot of broth solution was added. At each time point (1, 24, 48, and 72 h) the spent broth solution was decanted into new 50 ml plastic centrifuge tubes and stored for analysis. Once all broth solutions had been collected, they were centrifuged at 45,000 rpm for 15 mins and diluted further by taking 1 ml of the broth solution and making up to a total volume of 10 ml in plastic vials containing internal standard. All the broth solutions were analysed together by ICP-MS against standards of known silver concentrations (0.2, 0.5, 1, 2 and 5 ppm w/v). The reported results were normalized for a standard weight of 0.5000 g.

(49) Antimicrobial Effectiveness of Fibres and Competitive Wound Dressings (at Surgical Materials Testing Laboratory)

(50) A known weight (0.2-0.3 g) of the test material was placed in 10 ml of simulated wound fluid (50% serum/50% maximum recovery diluent) inoculated with a known number of micro-organisms and gently shaken at 35 C. Aliquots were removed at selected time points (0, 4, 24, 48, 72 h) and the organisms counted. Results are presented as either number of actual organisms or percentage reduction compared with the initial inoculum, and log reduction (Note: the initial microbial population was 2.2510.sup.6 cfu/ml for MRSA and 1.5910.sup.6 cfu/ml for Pseudomonas aeruginosa).

(51) Antibacterial Activity Assessment of Fibre Samples: Zone of Inhibition

(52) The method of assessment was based on the standard method outlined in AATCC TM 147-2004 using Staphylococcus aureus (Gram positive) and Klebsiella pneumoniae (Gram negative) as test bacteria.

(53) The zone of inhibition (ZOI) defined as clear area of no growth of a microorganism, cultured onto the surface of an agar growth medium, in proximity to the borders of a specimen placed in direct contact with this agar surface was evaluated using the simple equation: W=(TD)/2; where W is the width of clear zone of inhibition in m or mm T is the total diameter of test specimen and clear zone in m or mm.

(54) Results

(55) The Fibre absorbency of the calcium alginate and psyllium polymer fibres containing 1,2-propanediol of example 2 was: saline 30-50 g/g.

(56) The test results of the Calcium alginate and psyllium polymer fibres containing 1,2-propanediol and antimicrobial silver ions of example 3 were: Fibre absorbency: saline 37 g/g; Silver content of the fibre: 0.6%; Zone of inhibition: 2221 m for S. aureus and 883 m for Klebsiella.

(57) The test results of the alginate and psyllium polymer fibres containing 1,2-propanediol and antimicrobial silver, copper and zinc ions of example 8 were: Fibre absorbency: saline 22-25 g/g; Zone of inhibition (24 h): 1924 M for S. aureus and 3796 m for Klebsiella. Percentage reduction (72 h-7 days): 99.99% for MRSA and Pseudomonas aeruginosa.

(58) The test results of a comparison fibre batch containing Aquacel Ag fibres were: Fibre absorbency: 20-22 g/g; Zone of inhibition: 2796 m for S. aureus and 1150 m for Klebsiella. Percentage reduction (72 h-7 days): 99.99% for MRSA and Pseudomonas aeruginosa.

(59) These results suggest that the fibres produced following the method described with reference to FIG. 2 resulted in fibres which were almost equally effective against both gram negative and positive microbes. This is not always the case with most available commercial antimicrobial wound dressings.

(60) The test results of the Alginate, CMC and psyllium polymer fibres containing 1,2-propanediol, lecithin and antimicrobial silver, copper and zinc metal ions of example 8 were Fibre absorbency: saline 30-35 g/g; Zone of inhibition: 2348 m for S. aureus and 2308 m for Klebsiella.

(61) The absorbency in solution A of the swellable fibres produced by examples 14 to 20 in addition to the retention performance (liquid uptake) are detailed in table 2

(62) TABLE-US-00002 TABLE 2 Absorbency and retention performance results for examples 14 to 20 Solution A Absorbency Retention Example Composition g/g g/g 14 AF-PG140703-HM 16.36 19.59 15 *AF-140704-PG-HM 14.98 18.11 16 AF-PG-LE-140714-HM 18.67 22.27 17 AF-CMC-PG-LE-140804-HM 30.60 36.54 18 AF-CMC-PG-LE-140806-HM/HG 23.92 29.00 19 PF-CMC-PG-LE-140807-HM/HG 26.40 32.65 20 PF-CMC-PG-LE-140812-HM/HG 31.65 37.00 AFAlginate fibre without psyllium; PFalginate fibre with psyllium; Ppsyllium; HMHigh M Na-alginate (Manucol DH); HGHigh G Na-alginate (Protanal LF 10/60FT) *Alginate dissolved before addition of PG