Suppositories & Pharmaceutical Incompatibilities

 UNIT-4

Suppositories & Pharmaceutical Incompatibilities

Introduction to Suppositories

Suppositories are solid dosage form of medicament which is made for insertion into the body cavities. They may be Conical or avoid medicated solids intended for insertion into several cavities of the body other than mouth are known as Suppositories. This term was derived from the Latin word suppositum, meaning “to place under." They may be inserted in the rectum, vagina, and to a lesser extent, the urethra for local or systemic effects. Rectal and urethral suppositories usually employ vehicles that melt or soften at body temperature, whereas vaginulid suppositories, sometimes called y7e.Y.Yzr/ ie.Y, are also made as compressed tablets that disintegrate in the body fluids exert localized or systemic effects.

Types of Suppositories

Rectal suppositories: These are meant for insertion into the rectum for producing systemic effect. The rectal suppositories meant far adults usually weigh h 2 gm and are torpedo shape, whereas the suppositories made for children are much smaller in size as compared to the adult suppositories. Children's suppositories weigh about 1 gm.  The rectal suppositories which are used for systemic effects may contain analgesics, antispasmodic, Tran equalizers and sedative effects. Other than other these are used for antiseptic action, local anesthetic action, for lubricating, soothing purposes. The rectal suppositories are used for evacuating bowel by irritating mucous membrane of rectum or by lubricating the membrane.

Vaginal suppositories: The vaginal suppositories are also known as Pessaries. They are meant for insertion into the vag inal cavities. They weig h about 3- 5 gm and are molded in globular or oviform shape or compressed on a tablet press into conical shapes. The vaginal suppositories are larger than the rectal suppositories. They are used for their local action in vagina.

Urethral suppositories: These are also called as bougies and are of pencil shape. The urethral suppositories are meant for insertion into the urethra. The urethral suppositories intended for males weigh 4 gm each and are 100-150 mm long and those for females are 2 gm each and 60-7S mm in length.

Nasal suppositories: The nasal suppositories are also called as nasal bougies or buginaria. The nasal suppositories are meant for introduction in to nasal cavity. They are usually prepared with glycerogelatin base. They have similar shape as that of the urethral bougies. They weigh about 1 gm and have length of 9-10 cm.

Ear cones: Ear cones are used for insertion into the ear. They are also known as Aurinaria. They are used rarely. For preparation of ear cones generally theobroma oil is used as base. They are prepared in urethral bougies mould and cut according to size.

Advantages

1.       Suppositories can exert local effect on rectal mucosa.

2.       It is used to promote evacuation of bowel.

3.       It avoid any gastrointestinal irritation.

4.       Suppositories can be used in unconscious patients (e.g. during fitting).

5.       Suppositories can be used for systemic absorption of drugs and avoid first-pass metabolism.

6.       Babies or old people who cannot swallow oral medication.

7.       It is useful for post operative people who cannot be administered oral medication.

8.       A very suitable dosage form for people suffering from severe nausea or vomiting. Disadvantages of Suppositories

1.     Suppositories have a problem of patient acceptability .

2.     In some cases, the total amount of the dru g must be given will be either too irritating or in greater amount than reasonably can be placed into suppository.

3.     Incomplete absorption may be obtained because suppository usually promotes evacuation of the bowel.

4.    Suppositories are not suitable for patients suffering from diarrhea.

Ideal Properties of Suppositories Bases

1.       It should melt at body temperature or dissolves in body fluids.

2.       It should be good in appearance.1.       It should be non-toxic and non-irritant.

2.       It should be compatible with any medicament.

3.       Suppositories should releases medicament readily.

4.       It should be easily mounded and removed from the moulid. It shrinks sufficiently on cooling to release itself from the mold without the need for mold lubricants.

5.       It should be stable to heating above the melting point.

6.       It should be easy to handle and should retain its shape while handling.

7.       It should be stable on storage such that it does not change color, odor, or drug release pattern.

8.       Acid value is below 0.2, saponification value ranges from 200 to 245, and iodine value is less than 7.

9.      The "water number" is high, i.e., a high percentage of water can be incorporated in it.

Types of Bases

Fatty Bases.
Emulsifying Bases.
Water Soluble or Miscible Bases.

Methods of Preparation

Suppositories can be prepared by one of three method s:

1.   Hand Rolling

• It is the simplest and oldest method of suppository preparation and may be used when only a few supositories are to be prepared in a cocoa butter base. It has the advantage of avoiding the necessi of heating the cocoa butter

• By triturating grated cocoa butter and active ingredients in a mortar a plastic-like mass is prepared. The mass is formed into a ball in the palm of the hands, then rolled into a uniform cylinder with a large spatula or small flat board on a pill tile. The cylinder is then cut into the appropriate number of pieces which are rolled on one end to produce a conical shape.
  

• The suppository "pipe" or cylinder tends to crack or hollow in the center, especially when the mass is insufficiently kneaded and softened.

 2. Compression Molding

Compression molding is a method of preparing suppositories from a mixed mass of grated suppository base and medicaments which is forced into a special compression n Mould using suppository making machines. The suppository base and the other in rodents are combined by thorough mixing. The base softens because of the friction in the process. A mortar and pestle can be used for small scale. On the other hand, the large-scale manufacturing involves mechanically operated kneading mixers and a warmed mixing vessel. In the compression machine, the suppository mass is placed into a cylinder which is then closed. After that from one end pressure is applied to release the mass from the other end into the suppository Mould or die. When the die is filled with the mass, a movable end plate at the back of the die is removed and when additional pressure is applied to the mass in the cylinder, the formed suppositories are ejected. The end plate is returned, and the process is repeated until all of the suppository mass has been used. When active ingredients are added, it is necessary to omit a portion of the suppository base, based on the density factors of the active ingredients

  3.  Fusion Moulding

Fusion Moulding process involves the following steps.

•         Firstly melting the suppository base.

•         Then the drug is either dispersed or dissolved in the melted base.

•         The mixture is then removed from the heat and poured into a suppository mould.

•         The melt is allowed to congeal.

•         Now the suppositories are removed from the mould.

Suppository Moulds