Paste (rheology)

In physics, a paste is a substance that behaves as a solid until a sufficiently large load or stress is applied, at which point it flows like a fluid. In rheological terms, a paste is an example of a Bingham plastic fluid.

Pastes typically consist of a suspension of granular material in a background fluid. The individual grains are jammed together like sand on a beach, forming a disordered, glassy or amorphous structure, and giving pastes their solid-like character. It is this "jamming together" that gives pastes some of their most unusual properties; this causes paste to demonstrate properties of fragile matter.

Examples include starch pastes, toothpaste, mustard, and putty.

In pharmacology, paste is a basic pharmaceutical form. It consists of a fatty base (e.g., petroleum jelly) and at least 25% of a solid substance (e.g., zinc oxide). Pharmaceutical pastes are typically intended for external application to the skin. They are usually thick and do not melt at physiologic temperatures.[1]

## References

1. ↑ Juch, R & Rufli, Th & Surber, Christian. (1994). Pastes: What Do They Contain? How Do They Work?. Dermatology (Basel, Switzerland). 189. 373-7. doi:10.1159/000246882.

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Routes of administration, dosage forms

Oral|

| Digestive
tract (enteral)|

| Solids|

* Pill
* Tablet
* Capsule
* Pastille
* Time release technology
* Osmotic delivery system (OROS)

|
|

Liquids|

* Decoction
* Elixir
* Electuary
* Emulsion
* Extended-release syrup
* Effervescent powder or tablet
* Herbal tea
* Hydrogel
* Molecular encapsulation
* Powder
* Softgel
* Solution
* Suspension
* Syrup
* Syrup Concentrate for dilution and/or addition of carbonated water
* Tincture

Buccal (sublabial),
sublingual|

| Solids|

* Orally disintegrating tablet (ODT)
* Film
* Lollipop
* Sublingual drops
* Lozenges
* Effervescent buccal tablet
* Chewing gum

|

Liquids|

* Mouthwash
* Toothpaste
* Ointment
* Oral spray

Respiratory
tract|

| Solids|

* Smoking device
* Dry-powder inhaler (DPI)

|
|

Liquids|

* Anaesthetic vaporizer
* Vaporizer
* Nebulizer
* Metered-dose inhaler (MDI)

Gas|

* Oxygen mask and Nasal cannula
* Oxygen concentrator
* Anaesthetic machine
* Relative analgesia machine

Ophthalmic,
otologic, nasal]]|

* Nasal spray
* Ear drops
* Eye drops
* Ointment
* Hydrogel
* Nanosphere suspension
* Insufflation
* Mucoadhesive microdisc (microsphere tablet)

Urogenital|

* Ointment
* Pessary (vaginal suppository)
* Vaginal ring
* Vaginal douche
* Intrauterine device (IUD)
* Extra-amniotic infusion
* Intravesical infusion

Rectal (enteral)|

* Ointment
* Suppository
* Enema
* Solution
* Hydrogel
* Murphy drip
* Nutrient enema

Dermal|

* Ointment
* Topical cream
* Topical gel
* Liniment
* Paste
* Film
* DMSO drug solution
* Electrophoretic dermal delivery system
* Hydrogel
* Liposomes
* Transfersome vesicles
* Cream
* Lotion
* Lip balm
* Medicated shampoo
* Dermal patch
* Transdermal patch
* Contact (rubbed into break in the skin)
* Transdermal spray
* Jet injector

Injection,
infusion<br />(into tissue/blood)

| Skin|

* Intradermal
* Subcutaneous
* Transdermal implant

|
|

Organs|

* Intracavernous
* Intravitreal
* Intra-articular injection
* Transscleral

Central nervous system|

* Intracerebral
* Intrathecal
* Epidural

Circulatory,
musculoskeletal|

* Intravenous
* Intracardiac
* Intramuscular
* Intraosseous
* Intraperitoneal
* Nanocell injection
* Patient-controlled analgesia pump
* PIC line

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