Shapes and sizes of tablets

A great variety of shapes and sizes is available among medical tablets. One knows that the most common shape of the tablet is a circular body with flat or slightly convex sides. In the Scandinavian countries where the Pharmacopoeia provides official specification of formula, the method of tablet making, the size and shape are also specified officially. In selecting of particular shapes and sizes the primary consideration is ethical. It is generally recognized that prepared tablets must have a pleasing appearance. It is important that the tablet for making solutions is required to dissolve as quick as possible. This will require a larger diameter than average tablets of the same weight. A tablet for oral using should be flat and thick enough. While it is slowly dissolving in the mouth the patient will feel a pleasant lasting sense. The efficiency of the tablet depends on this effect.

Similarly, coated tablets which have a more convex shape are harder than other ones. It is more convenient to have the thinnest edges because it is easier to cover a thin edge during the coating process. In addition, it was found that preparing of very convex tablets was more difficult. The density of compressing substance is also important factor. Thus a lighter and less dense material needs a bigger punch – press machine than a similar weight of more dense material. In the process of tablet making different pressures are used for the compressing of various shapes of tablets. The flat-faced tablets show a relatively greater strength than the convex-shaped ones.

Examination question №19

Antibiotics

Since the end of the twentieth century modern medicine has been making an extensive use of various antibiotics. It should be noted that antibiotics are powerful agents in combating infections. The problem of discovering new antibiotics can be most successfully solved at special research institutes which may have a small experimental plant producing preparations of new antibiotics.

Russia has several research institutes working in this field. Before new generation of antibiotics made its appearance Russian science had produced a series of new effective drugs, such as albomycin, etc. This practically non-toxic preparation has found wide application in the treatment of pneumonia in newborn and small children. It is also successfully used in obstetric and gynecological practice. Surgeons have to use it during the treatment of the septic processes caused by staphylococci which can resist other antibiotics. It has been established experimentally that the composition of its molecule includes iron and it has a peculiar mechanism of affecting the bacteria.

Mention must also be made of tetracyclines, such as chlortetracycline. It was introduced after chlorphenol had been discovered. Therefore chlortetracycline was considered the second broad – spectrum antibiotic developed for therapeutic purposes. It was isolated in 1948 from biomycin. Because of its yellow colour it was marked as auremycin. Another antibiotic of this series is tetracycline. It has been found that it possesses great advantages over its sister compounds. It may produce less toxic effect and penetrate the cerebrospinal fluid to a much greater extent. It has been stated that in ordinary use the tetracyclines can be given orally in doses of 250 mg.

Поиск по сайту: