such sequestrant agents present in the gastrointestinal tract are mainly understood as deriving from diet , such as , for example , fibres like bran , or coffee , or from pharmaceutical products used for other therapies employed at the same time , such as antacids . the thus - prepared formulations of thyroid hormones for oral use include both solid forms , namely capsules , and liquid forms , such as solutions to be administered in drops or in disposable containers . the characteristics and advantages of this invention are explained in detail in the following description . the following examples are provided to aid disclosure , and do not limit this invention . soft gelatine capsule with a shell and fill , or inner phase , containing 100 μg levothyroxine t4 have been prepared as follows : 27 . 6 kg of anhydrous glycerine are added to 45 . 6 kg of purified water in a 150 litre turbo emulsifier ( olsa - italia ). the mixture is well shaken and taken to a temperature of 70 ° c . 46 . 8 kg gelatine is then added and the mixture continually shaken for a further 15 - 60 minutes . the mass is then de - aerated by applying a progressive vacuum until reaching a value ranging between + 0 . 8 and − 0 . 9 bars . b ) preparation of the fill ( for 100 mcg dose with 50 mg fill ) the levothyroxine is dissolved in 2 . 5 kg of 85 % glycerine , mixing with a mechanical stomacher until fully dissolved . separately , in a 25 litre turbo emulsifier ( olsa italia ), 2 . 48 kg of water and 1 . 0 kg of 85 % glycerine are suctioned . this mix is heated to 65 ° c .± 5 °. having reached the temperature , 3 . 5 kg of hydrolysed gelatine and 0 . 5 kg of gelatine 80 bloom are suctioned , mixed and de - aerated until a clear product is obtained with no agglomerates . at this point , the product , which has been kept at the temperature of 65 ° c .± 5 °, is cooled to 45 ° c .± 3 ° c . once this temperature has been reached , the solution containing the levothyroxine is added , mixing for at least 30 minutes . during this phase , both the vacuum and cooling are kept active , in order to take the product to the temperature of 38 ° c .± 2 °. the product obtained is discharged into a thermostat container and kept at 38 ° c .± 2 °. soft gelatine capsules were prepared with a 10 oval format and in accordance with the method known as the ‘ rotary die process ’. preparation of a glycerol - ethanol solution of sodium levothyroxine ( t4 ) with the addition of gelatine . 90 % of the ethanol ( 5 . 49 litres ) are poured into a 10 - litre steel container equipped with blade stomacher and lid . whilst being shaken , the t4 is added . shake slowly , keeping a flow of nitrogen until fully dissolved . the glycerol and hydrolysed gelatine , together with the ethanol solution containing the t4 , are poured into a 25 - litre turbo emulsifier ( olsa - italia ). wash the 10 - litre container with the remaining ethanol ( 0 . 61 litres ) and pour into the 25 - litre turbo emulsifier . continue to shake reasonably gently for 15 minutes in nitrogen atmosphere , and protected from the light . preparation of a glycerol - ethanol solution of sodium levothyroxine ( t4 ) with the addition of starch hydrolysates the final formula is obtained as described for example 2 , using the starch hydrolysate in lieu of the gelatine . experimental study on the sequestrant effect of fibres ; dissolution test with the aim of testing the effect of the formulae prepared in accordance with the previous examples , a dissolution test was carried out with increasing quantities of microcrystalline cellulose fibre ( 1 and 2 % p / v ). the test is based on the fact that an increasing concentration of cellulose in the system involves a proportional decrease of the t4 in the solution after filtration . the effect is entirely inhibited by the addition of a surfactant like sodium dodecyl sulphate sds 0 . 2 %. we can therefore conclude that the missing t4 is sequestered by the cellulose . the dissolution test for the solid oral forms is used as a quality test that shows the dissolution of the oral form and the quantitative liberation of the active ingredient available for the pharmacokinetics ( dissolution test euph 6 . 0 ( 2 . 9 . 3 ) and usp 30 ( 711 ). in the case of solid oral t4 tablets , the existing dissolution methods ( usp 30 - levothyroxine sodium tablets ) set out , as per protocol , the use of hydrochloric acid 0 . 01 n as a dissolution buffer in the presence of sds . given , however , the effect inhibiting sequester by the surfactant , as discussed above , the method must be altered , eliminating the sds from the buffer . the following equipment is used for the test : the figures of the attached drawings compare the dissolution curves with the percentage quantity of t4 passed in the solution on the y - axis , and the time ( t , minutes ) on the x - axis , as follows : fig1 compares the two dissolution curves of a famous t4 tablet available on the market ( eutirox ®), respectively without and with cellulose 2 %. the curves are obtained with the usp method modified without the addition of sds . fig2 compares the three dissolution curves of a t4 formula according to example 1 of this invention , respectively without and with cellulose , in one case 1 % and in the second case 2 %. in fig1 , the sequestrant effect of the cellulose with regards to t4 is clearly visible , with a dissolution profile lowered by approximately 10 up to 20 % as compared with the dissolution profile without cellulose . in fig2 , the graph shows that in the presence of 1 or 2 % microcrystalline cellulose , the t4 dissolution profile does not vary significantly as compared with the absence of fibre , as the curves can be almost superimposed . as such , it is clear how the invention allows for the attainment of the aim discussed initially .
the invention concerns the use of a substance chosen among animal or vegetable gelatine , peptones , dextrins , native or modified cyclodextrins , starch , and starch hydrolysates in the preparation of pharmaceutical forms for the oral administration of thyroid hormones to combat the action of sequestrant agents present in the gastrointestinal tract , and related pharmaceutical forms .