Rheology

Rheology

In this blog we are discussing about the Rheology, what is the Rheology, where is the Rheology used, what its application and why is rheology important in pharmacy. so friends read the blog till the end for full detail. 


What is rheology?

[Rheo means to 'flow' and logos means 'science'] 

The flow of the liquid is induced by applying stress (shear stress). the behavior of fluid at rest-state and during flow is different. the changes are evaluated at all stages of product life cycle. Flow property of a sample liquid is expressed in term of viscosity. Quantitatively, viscosity is an index of resistance to flow.

for example; ground nut oil, honey, syrup (sucrose solution), all resist the flow more in comparison to water or alcohol. Syrup has a large internal friction it pours slowly. 

Where is rheology used?

Rheology has programs in materials technology, engineering, geophysics, body structure, human biology and pharmaceutics. Materials science is applied in the manufacturing of many industrially essential substances, together with cement, paint, and chocolate, that have complicated glide characteristics.

What is rheology and its application?

Rheology has various applications in the pharmacy,

1. Standards of liquids: 

  • The viscosity of common liquid of pharmaceutical importance are standardized and reported. for example, liquid paraffin has the viscosity of less than 64 centistokes at 37.8 C. 

2. Manufacture of dosage forms: 

  • Material undergo processes such as mixing, flowing through pipes, filling into the containers etc.
  • Flow related changes influence the selection of mixing equipment.
  • The manufacture of simple liquids, gels, ointment, cream and paste are influenced.
  • If the material is highly viscous, heat is applied to convert gel-like consistency to liquid-like consistency, so that mixing can be effective under low viscosity condition.

3. Handling of drugs drugs for administration:

  • The syringibility of the medicine pouring of liquid from containers, extrusion of ointment from tubes all depend on the changes in flow behavior of dosage forms.
  • This also ensures compliance of the patient.
  • The words on the label such as shake well before use also indicate that flow behavior changes. 
  • After shaking the liquid flows out well through the neck of the container.
  • These helps in achieving patient compliance.

4. Quality control tools for protect evaluation:

  • The performance of the product is evaluated routinely for maintaining the behavior and to reduce batch to batch variability.
  • For example, dextran 40 and dextran 110 injections are analyzed by determining the viscosity rations at 37 C (IP).
  • Most of the cases, compendial testing is limited to fluids following Newtonian type.

5. Determination of molecular mass [molecular weight]:

  • Molecular weight of polymers such as albumin (protein), insulin (enzyme) and dextran (polysaccharides) can be determined from the viscosity measurements.

6. Viscosity improving substance:

  • Hydrocolloids and polymers are added to vehicle for maintaining the product consistency, in preparing suspensions and emulsions. 
  • The influence of these additives and their concentration are selected, so as to maintain the desired flow behavior.
  • These influence the physical stability and bioavailability of the drug.

7. Identification of diseases:

  • A change in consistency of the body fluids, mucus, blood, saliva etc., is used as an indicator of the severeness of the diseases.

8. Model for treatment of disease:

  • The effectiveness of drugs against disease such as mucoviscidosis can be tested by studying the consistency changes.

Why is rheology important in pharmacy?

Medications produced as semi-solids kind product inclusive of lotions, ointments and lotions are based totally on emulsion or suspension type systems such as  or more incompatible substances. In order to be manufactured, these dosage bureaucracy need precise flow homes in order that they may be placed into a field, continue to be stable through the years, distributed, dealt with and nicely applied to the affected location by means of sufferers. Rheology is consequently crucially crucial as it will immediately have an effect on the way a drug is formulated and evolved, the first-class of the uncooked and completed product, the drug efficacy, the manner a affected person adheres to the prescribed drug, and the overall healthcare value. It may be concluded that there are inherent and unbiased factors that have an effect on the float assets of a medicated cloth in the course of every stage of its production all of the way to its use.