Chapter 13 the Covering of tablets
Shells. Film coverings. Water-soluble coverings.
Coverings, soluble in gastric juice. Coverings, soluble in
Intestines. Insoluble coverings.
Covering tablets shells.
Drawing shells pursues the following purposes: to give to tablets
Beautiful appearance to increase their mechanical durability,
To hide unpleasant taste, a smell, to protect from influence
An environment (light, a moisture, oxygen of air) to locate
Or to prolong action of medicinal substance, to protect
Mucous membranes of a gullet and a stomach from destroying action
Medicinal substance. The coverings rendered on tablets, it is possible
To divide into 3 groups: drazhirovannye, film and pressed.
Drazhirovannye coverings - see. Technology of reception of drops.
Film coverings.
Are created on tablets by drawing a solution
Film-forming substance with the subsequent removal of solvent.
Thus on a surface of tablets it is formed thin (0,05-
0,2ìì) the shell. Film coverings depending on
Solubilities divide into the following groups: water-soluble,
Soluble in gastric juice, soluble in intestines and
Insoluble coverings.
Water-soluble coverings protect from mechanical damages,
But do not protect from influence of a moisture of air. Water-soluble
Shells form PVP, MTS, oksipropilenmetiltselljuloza, Na KMTS and
Other rendered as vodnoetanolnyh or water solutions.
Coverings, soluble in gastric juice. It is a film, which
Protect tablets from action of a moisture, but do not interfere fast
To their destruction in a stomach (during 10-30ìèí). Concern
The polymers having in a molecule assistants of the basic character,
Mainly amino groups, for example dietilaminometiltselljuloza,
benzilaminotselljuloza, paraaminobenzoaty sugars and
atsetiltselljuloza, etc. For a covering use solutions specified
Substances in organic solvents: ethanol, izopropanole,
Acetone.
Coverings, soluble in intestines. They locate medicinal
Substance in intestines, prolonging his action. For reception
Coverings use atsetilftalilTS, metaftalilTS,
polivinilatsetatftalat, ftalaty dekstrina, lactoses, mannita,
Sorbite, shellac (natural Naval Forces) For reception of a film use
The specified substances as solutions in ethanol, izopropanole,
etilatsetate, toluene, etc. solvents, HFI (. Sankt
Petersburg) has developed technology of a covering of tablets
A vodno-ammoniac solution of shellac and atsetilftalilTS. For improvement
Mechanical properties plenok to them add softener.
Insoluble coverings - a film with microporous structure.
Represent solutions etilTS and atsetilTS in ethanol,
izopropanole, acetone, toluene, chloroform, etilatsetate, etc. With
Addition of softeners. The mechanism of liberation
Medicinal substance: digestive juices will quickly penetrate
In time of the insoluble shell also dissolve medicinal
Substance or cause his swelling. In the first case
Medicinal substance diffundiruet through a film in the opposite
A direction, in the second - occurs having dug shells, then
The medicinal substance is liberated by usual way.
Methods of drawing of film coverings.
Drawing film coverings is carried out in drageeing
Boilers, installations of centrifugal action and in psevdoozhizhennom
A layer. The method of drawing of coverings in psevdoozhzhennom a layer is applied
For drawing water coverings, as drageeing boilers
Have low parameters warmly and massoperenosa and process
Coverings proceeds slowly, that reduces productivity
The device. Use of water coverings has a number of advantages:
Disappears necessity of catching and regeneration of solvent;
To prepare for water solutions it is easier, they it is better distributed on
Surfaces of tablets. For film water coverings use
Water solutions oksipropilmetplTS, ammonijnyh salts of shellac and
atsetilftalilTS. Before drawing of water coverings of a surface
Tablets give water repellency at the expense of drawing a layer
Vegetable oil. The device for drawing water film
Coverings it is developed LNPO "Progress".
At impossibility of use of a water film covering
The covering is applied on the basis of organic solvents. For
Drawings these coverings use drageeing boilers. This
The method is simple, differs high efficiency at
Use of coverings on the basis of organic solvents. For
Drawings a covering biconvex tablets are loaded in
The drageeing boiler. Before the beginning of process of a covering with
Surfaces of tablets the dust (with the help of an air jet leaves
Or vacuum). The covering solution is entered in the boiler by
Repeated razbryzgivanija (with the help established at
Apertures of the boiler of an atomizer).
For drawing film coverings on the basis of organic
Solvents installation ÓÇÖ-25 having closed is applied
System of catching and regeneration of solvent.
Installation ÓÇÖ-25 works as follows: in drageeing
The boiler rotating from a drive, are loaded subject to a covering
Tablets. The system is isolated. In the collection prepares covering
A solution. The system of pipelines is filled by nitrogen. The fan
Nitrogen moves in a heater where it is heated up up to set
Temperatures, then, entering into the boiler, washes mixed
Tablets on which with the help raspylivatelja it is rendered
A covering solution. Nitrogen with pairs solvent acts in
The condenser where solvent is condensed and going to in
The collection. The drained nitrogen again acts on the fan. This
The cycle repeats repeatedly up to a full covering of tablets. On
The termination of process it is made razgermetizatsija a casing
The drageeing boiler, for what preliminary from system with
The help of vacuum nitrogen with pairs solvent leaves. The boiler
Opens, the rest parogazovoj knead leaves from the boiler local
The pump. A covering of a tablet are unloaded by an inclination of the boiler.
The weight of the tablets loaded in the boiler, makes 25 kg.
Duration of a cycle no more 4÷.
Napressovannye coverings.
Napressovannye coverings are the dry coverings rendered on
Tablets by pressing by special machines (ÐÒÌ-41Ä),
Which represent a combination of two machines: rotational-
Usual type for pressing tablets and special - for
Receptions on them napressovannogo coverings. On the first rotor
Tablets which the passing device go are pressed
On the second rotor in which matrix the covering solution moves
And the tablet is pressed finally. Principal causes,
Constraining wide application of this method, are more
Low characteristics of coverings in comparison with plenkami and less
An attractive packaging.
Trituratsionnye tablets.
Trituratsionnymi the tablets formed from humidified are called
Weights by her vtiranija in the special form with the subsequent
Drying. As against pressed, trituratsionnye tablets not
Treated to action of pressure: coupling of particles of these tablets
It is carried out only in result autogezii at drying,
Therefore trituratsionnye tablets possess smaller durability, than
Pressed. Trituratsionnye tablets make in those
Cases when use of pressure is undesirable or
It is impossible. It can take place when a dosage
Medicinal substance it is small, and addition of a plenty
A plenty of auxiliary substances it is inexpedient.
To make such tablets because of the small size (d = 1-2 mm) on
To the machine it is technically difficult for a tablet. Trituratsionnye tablets
Make and when action of addition can call to
- l change of medicinal substance. For example, at reception
Tablets of nitroglycerine at use of addition can
To take place explosion. And more trituratsionnye tablets expediently
To be going when tablets, quickly are necessary
And it is easy rastvorjajushchiesja in water. For their manufacturing are not necessary
Sliding substances which are insoluble
Connections. Trituratsionnye tablets are porous and
Fragile and consequently they are quickly dissolved at contact with
A liquid that is convenient by manufacture of tablets for injections and
Eye drops.
As auxiliary substances for trituratsionnyh tablets
Use lactose, saccharose, glucose, kaolin, ÑàÑÎ3. At them
Reception poroshkoobraznuju the mix is humidified with 50-70 % spirit up to
Receptions of plastic weight, which then with the help shpatelja
Rub in a plate - a matrix placed on glass. Then with
Damp tablets are pushed out by the help of pistons of punches from
Matrixes also are dried on air or in a drying case at
To temperature 30-40? C. On other way drying of tablets
It is carried out, it is direct in plates and with the help
Punches dried already up tablets are pushed out.
