DRUG DOSAGE FORMS & DELIVERY SYSTEMS


Paste

Dermatologic paste are ointment like preparations employed in practice of dermatology

Usually stiffer, less greasy and more absorptive than ointments such as starch, ZnO, CaCO3, and talc in the base

Characteristics
  1. Stiffness and impenetrability, not suited for hairy parts of the body
  2. Absorbs serous secretions and are preferred for acute lesions having a tendency to ooze
  3. Are less penetrating than ointment
  4. Are less macerating than ointment
Types of Paste
  • Dermatologic Paste
  • Paste for injection

Plasters

Substances intended for external application, made of such materials and consistency as to adhere to the skin and thereby attach as dressing.

Purposes of Plasters
  • To afford protection and mechanical support.
  • To furnish an occlusive macerating action.
  • To bring medication into close contact with surface of skin.
 

BACK PLASTERS are made of heavy cotton or wool and cotton backing to provide warmth and support.

They are usually used for backache, sore shoulders, sore arms, and other muscular aches.

The active consituents of back plaster is OLEORESINS OF CAPSICUM

EXAMPLES: CHILLI PLASTER; HOT SALONPAS

Packaging Semi-Solid Preparations
  1. Topical dermatologic – jars or tubes
  2. Ophthalmic, nasal, vaginal, rectal – tubes
  3. Ointments – ointment jars – opaque glass or plastic; some colored green, amber or blue
  4. Ointment jars – about 0.5 ounce to 1 pound
  5. Jars and tubes – must be tested for compatibility and stability
  6. Ointment tubes – aluminum or plastic
  7. Ophthalmic, rectal, vaginal, aural or nasal – packaged with special applicator
  8. Aluminum tubes – coated with epoxy resin, vinyl lacquer to eliminate any interaction with the content
  9. Plastic tubes – High or low density polyethylene (HDPE or LDPE), polypropylene (PP), polyethylene terepththalate (PET), plastics, foil or paper laminate sometimes 10 layers thick
  10. LDPE – soft and resilient, provides good moisture barrier
  11. HDPE – less resilient but provides a superior moisture barrier
  12. PP – has a high level of heat resistant
  13. PET – transparency and high degree of chemical compatibility
  14. Multiple dose tubes – continuous thread closures
  15. Single dose tubes – “tear away tip”
  16. Tubes – capacities of 1.5, 2, 3.5, 5,15,30,45,60,120 g
  17. Ophthalmic ointments – collapsible plastic or aluminum