It's all about B.pharm

III/IV   Andhra University college of pharmaceutical sciences scheduled exams from July 5th 2021. 05/07/2021-industrial pharmacy-l 06/07/2021-pharmacology ll 07/07/2021- pharmacognasy&phytochemistry 2 08/07/2021- Pharmaceutical jurisprudence 09/07/2021- Industrial pharmacy -l (practical) 10/07/2021- Pharmacology-ll(practical) 11/07/2021- Pharmacognasy&phytochemistryll(practical)              

 3.carrier mediated transport - the presence of specialised transport mechanisms without which many essential water-soluble nutrients like monosacharrides ,aminoacids and vitamins will be poorly absorbed. --the mechanism is thought to involve a component of the membrane called as the carrier. --the carrier,that binds reversible or non covalent with the solute molecules to be transported. --this carrier-solute complex transverse across the membrane to the other side where it dissociated & discharges the solute molecule--the carrier then returns to its original site to complete the cycle by accepting a fresh molecule  of solute . --the carrier may be an enzyme or some other component of the membrane.  --the important characteristics of carrier mediated transport are; 1.the transport process is structure specific(I.e. the carriers have affinity for and transfer a drug of specific chemical structure only ;generally the carriers have special affinity for essential nutrient...

 2.pore transport - It is also called as convective transport, bulk flow or filtration. -the process is important in the absorption of low molecular weight (less than 100). -low molecular size (small than the diameter of the pare) generally water-soluble drugs through marrow, aqueous filled channels or pores, in the membrane structure .ex :Urea, H₂o & Sugars.... * Chain-like.. or linear compounds of molecular weight upto 400 daltons can be absorbed by filtration. * The driving force is constituted by the hydrostatic pressure/ the asmotic differences across the membrane due to which bulk flow of water along with solid molecules occurs through, aqueous such channels  →water flux that promotes such a transport is called as solvent drug. -drug permeation through water filled channels or of particular importance in renal excretion,removal of drug from the cerebrospinal fluid and entry of drugs into the liver. Note:next topic will be continued I  next blog

   Mechanism of drug absorption  The principle Mechanisms for transport of drug molecules across the cell membrane in order of their importance  are 1.passive diffusion 2.pore transport  3.facilitated diffusion  4.active transport  5.ionic or electrochemical diffusion  6.ion-pair transport  7.endocytosis 1.passive diffusion -also called as non-ionic diffusion. -it is the major process for absorption  of more than 90% of the drugs. -the driving force for this process is the concentration or electrochemical gradient  -it is defined as the difference in the drug concentration on either side of the membrane.  -drug movement is a result of the kinetic energy if molecules. -since no energy is required ,the process is called as passive diffusion.  -during passive diffusion ,the drug present in aqueous solution partitions and dissolves in the lipid material of the membrane and finally leaves it by dissolving again in an aqueous...

Gastrointestinal absorption of drugs . ●The oral route of drug administration is the most common for systemically acting drugs. ●before proceeding to discuss absorption aspects, a brief description of cell membrane structure  and physiology  is necessary. ●cell membrane:structure and physiology -for a drug to be absorbed and distributed into organs and tissues and eliminated from the body,it must pass through one or more biological membranes/barriers at various locations. Such a movement of drug across the membrane is called as "drug transport". -the cellular membrane consists of a double layer of amphillic phospholipid molecules. -the membrane is a mayonnaise sandwich where a biomolecular layer of lipids is contained between 2 parallel monomolecular layers of proteins. -Hydrophobic core of the membrane is responsible for the relative impermeability of polar molecules. -aq.filled pores or perforations of 4 A° in diameter are also present in the membrane  structure through...

      Absorption of drugs Drugs that have to enter the systemic circulation  to exert their effect can be administered by 3 major methods: They are 1.the enteral route-GI/buccal/rectal/sublingual. 2.the parenteral route-all routes of administration through or under one or more layers of skin. 3.the topical route-includes,skin,eyes or other specific membranes.

 _introduction to Biopharmaceutics.