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Disquisition on Routes of Drug Administration
This document discusses various routes of drug administration. It begins by defining key terms like pharmacology and first-pass effect. It then identifies the appropriate routes for different drug formulations like ear drops, injections, insulin etc. The various routes covered are oral, sublingual, rectal, parenteral routes like intravenous, intramuscular, subcutaneous etc. Factors influencing route selection and new advanced drug delivery systems are also discussed. The document is authored by Dr Lokendra Sharma and aims to provide an overview of different routes of drug administration.
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Disquisition on Routes of Drug Administration
- 1. Disquisition on Routesof Drug Administration Dr Lokendra Sharma Professor Pharmacology SMS Medical College Jaipur
- 2. 1. Identify theterm used for the study of drugs and their effect on the body : A Pharmacy B Pharmaceutical C Pharmacology D Physiotherapy (C)
- 3. 2.What is thefirst-pass effect? first-pass metabolism or presystemic metabolism Metabolism of drug in the gut wall or portal circulation before reaching systemic circulation so the amount reaching system circulation is less than the amount absorbed.
- 4. 3. Identify theroute of administration for ear drops : A Oral administration B Parenteral administration C Topical administration D Subcutaneous (C)
- 5. 4. Identify theterm used to describe an injection that is given just under the skin : A Subcutaneous B Intramuscular C Intravenous D Epidural A.
- 6. 5 .Which ofthe following is the appropriate route of administration for insulin? A) Intramuscular B) Intradermal C) Subcutaneous D) Intravenous (C)
- 7. 6.The nurse isto administer an iron injection to an adult. How should this be administered? A) Subcutaneous in the arm B) Intradermal in the forearm C) Intramuscular in the deltoid D) Z track intramuscular in the gluteal (D)
- 8. 7.The permeation ofdrugs across cellular membranes is dependent on what drug properties and (local) circumstances? • Drug solubility; drug concentration gradient; drug ionization; surface area; vascularity
- 9. 8. The nurseprepares IM injection that is irritating to the subcutaneous tissue. Which of the following is the best action in order to prevent tracking of the medication: A) Use a small gauge needle B) Apply ice on the injection site C) Administer at a 45° angle D) Use the Z-track technique (D)
- 10. The route ofadministration (ROA) that is chosen may have a profound effect upon the speed and efficiency with which the drug acts.
- 14. Dr L KSharma
- 15. Q…Ion Trapping cont: DrL K Sharma Body fluids where a pH difference from blood pH will favor trapping or reabsorption: stomach contents small intestine breast milk aqueous humor (eye) vaginal secretions prostatic secretions
- 16. Ion Trapping: Dr LK Sharma Kidney: Nearly all drugs filtered at the glomerulus: Most drugs in a lipid-soluble form will be absorbed by passive diffusion. To increase excretion: change the urinary pH to favor the charged form of the drug: Q..Weak acids: excreted faster in alkaline pH (anion form favored) Q.. Weak bases: excreted faster in acidic pH (cation form favored)
- 17. Systemic Enteral Parenteral • OralInhalational • Sublingual Injections (Intravenous,Intramuscular Subcutaneous Intraarterial,Intraarticular Intrathecal ,Intradermal) • Rectal Transdermal
- 18. Local Skin topical Intranasal Ocular drops Mucosal-throat, vagina,mouth, ear Inhalational Transdermal
- 19. Factors governing choice ofroute 1. Characteristics of the drug. 2. Emergency/routine use. 3. Site of action of the drug—local or systemic. 4. Condition of the patient (unconscious, vomiting, diarrhoea). 5. Age of the patient. 6. Effect of gastric pH, digestive enzymes and fi rst-pass metabolism. 7. Patient’s/doctor’s choice (sometimes).
- 20. Systemic route Enteral Routes Inthis route the drug through Gastrointestinal Tract is absorbed into the blood. This route is further classified into three classes: Oral Sublingual - placed under the tongue Rectum - Absorption through the rectum
- 21. (1) Oral Route: Inthis route the drug is placed in the mouth and Swallowed. It is also called per oral (p.o.) Advantages of Oral Route • Convenient - Can be self administered, pain free, easy to take • Absorption - Takes place along the whole length of the gastro intestinal tract • Cheap - Compared to most other parenteral routes
- 22. Disadvantages of OralRoute • drug not absorbed in GIT e.g. aminoglycosides • First-pass effect e.g. lignocaine. • Irritation to gastric mucosa – nausea and vomiting • Destruction of drugs by gastric acid and digestive juices.g. insulin • Effect too slow for emergencies • Unpleasant taste of some drugs • Unable to use in unconscious patient
- 23. First-pass effect Where ? Liver Gutwall Gut Lumen Result ? Low bioavailability. Short duration of action (t ½)..
- 25. Examples of drugswhich undergo marked First Pass Effect:- • Imipramine, • Propranolol, • Lidocaine
- 26. The example ofdosage forms which are used by oral route include 1. Tablet 2. Capsules 3. Syrups etc
- 27. 2.Sublingual/Buccal Some drugs aretaken as smaller tablets which are held in the mouth or under the tongue. Example : Nitroglycerine tablets Advantages rapid absorption drug stability avoid first-pass effect Can be used in emergencies
- 28.
- 29. 3.Rectal Route: given asa suppository. Rectum's wall is thin with rich blood supply, so drug is readily absorbed.
- 30. Vaginal Route As solution,tablet, cream, gel, suppository, or ring. Drug is slowly absorbed through the vaginal wall. Used to give estrogen to women at menopause, because the drug helps prevent thinning of the vaginal wall, an effect of menopause
- 31. Urethral Route Drugs aregiven through the urethra Advantages of rectal/urethral/vaginal routes:- 1. Unconscious patients and children 2. If patient is having nausea or vomiting
- 32. Disadvantages rectal/urethral/vaginal routes 1.May cause irritation 2. Absorption may be variable Examples:- 1. Suppositories 2. Vaginal Bogies 3. Urethral Bogies
- 33. II Parenteral Routes:- Inthis route of administration the drug does not pass through the gastrointestinal tract. It directly reaches to the blood.
- 34. It can furtherbe classified into two classes:- 1. With injections:- eg. Intravascular, Intramuscular, Subcutaneous 2. Without injections/Inhalationals: -. e.g. Inhalations.
- 37. Direct delivery ofdrug in to systemic circulation without intestinal mucosa Intradermal (I.D.) (into skin) Subcutaneous (S.C.) (into subcutaneous tissue) Intramuscular (I.M.) (into skeletal muscle) Intravenous (I.V.) (into veins) Intra-arterial (I.A.) (into arteries) Intrathecal (I.T.) (cerebrospinal fluids ) Intraperitoneal (I.P.) (peritoneal cavity) Intra - articular (Synovial fluids)
- 38. Advantages of Parenteralroute high bioavailability • Rapid action (emergency) • No first pass metabolism Disadvantages Infection Sterilization. Invasive assistance require Pain Needs skill Anaphylaxis Expensive
- 39. Suitable for –Vomiting &unconsciousness –Irritant & Bad taste drugs. – No gastric irritation – No food-drug interaction Dosage form: Vial or ampoule
- 40. • Ampoule ivinfusion Vial
- 41. 1. Intravascular Advantages:- 1. Precise,accurate and almost immediate onset of action 2. Large quantities can be given, fairly pain free 3. Can be given to unconscious patients. 4. Quick action 5. Drugs having unpleasant taste can be given.
- 42. Disadvantages:- 1. Pain atthe site of injection. 2. Greater risk of adverse effects a. High concentration attained rapidly b. Risk of embolism
- 43. 2. Intramuscular:- drug isgiven into the muscles , absorbs into the blood. 1. Very rapid absorption of drugs in aqueous solution 2. Depot and slow release preparations 3. Pain at injection sites for certain drugs
- 44. Subcutaneous:- • Drug isdeposited in loose subcutaneous tissue – rich nerve supply- irritant drugs cannot be given. • Less vascular- slow absorption than im route • Avoid in shock pt – vasoconstriction • Only Small volume can be injected • minimizes the risks associated with intravascular injection • Depot preparation can be injected- Dermojet, Pellet implantation, Sialistic and biodegradable implants.
- 46. Intradermal Route Inj intoskin raising bleb – BCG Vaccine, Sensitivity test Intrathecal/intraventricular It is sometimes necessary to introduce drugs directly into the cerebrospinal fluid. For example, amphotericin B is used in treating Cryptococcal meningitis
- 50.
- 51. for gasesor aerosol drugs provides the rapid delivery of a drug across the large surface area of the mucous membranes almost as rapidly as with IV injection.
- 52. effective and convenientfor patients with respiratory complaints ( asthma, or COPD) because the drug is delivered directly to the site of action and systemic side effects are minimized Examples : albuterol, corticosteroids, such as fluticasone
- 53. Advantages of Inhalational 1.Rapid onset of action due to rapid access to circulation. 2. Pain not occurs because injection is not used. 3.Provide local action 4 Minor systemic effect 5. Low bioavailability 6. Less side effects. 7. No first pass effect Examples:- 1. Inhalers 2. Aerosols
- 54. Disadvantages • Only fewdrugs can be used Nebulizer Inhaler
- 55. Local/Topical Route ofDrug Administration in this route the drug is applied on the skin and mucous membrane for the local action. • Mucosal membranes (eye drops, antiseptic, sunscreen, callous removal,nasal, etc.)
- 56. • Skin Dermal -Rubbing in of oil or ointment (local action). Transdermal - Absorption of drug through skin (systemic action) i. Stable blood levels ii. No first pass metabolism iii. Drug must be potent Examples 1. Creams 2. Lotions 3. Gels etc
- 57. Intranasal • Involves administrationof drugs directly into the nose. Agents include nasal decongestants such as the anti-inflammatory corticosteroid • Eg: Desmopressin for diabetes insipidus; salmon calcitonin for osteoporosis • The abused drug, cocaine, is generally taken by intranasal sniffing.
- 58. Onset of actionof different routes is as follows:- • Intravenous 30-60 seconds • Intraosseous 30-60 seconds • Inhalation 2-3 minutes • Sublingual 3-5 minutes • Intramuscular 10-20 minutes • Subcutaneous 15-30 minutes • Rectal 5-30 minutes • Oral 30-90 minutes • Topical/transdermal (topical) variable (minutes to hours)
- 59. New Drug deliverysystem • Definition : NDDS Therapeutic systems that incorporate drugs in a dosage form that releases the medication at a predetermined site at a predetermined rate over an extended period of time from a single application
- 60. Advantages Delivery of thedrug a) controlled rate b) slow delivery c) targeted delivery 2. Longer duration of action 3. ↑ bioavailability 4. ↓ Adverse Effects 5. ↑ compliance
- 61. Types 1) Prolong release •Oral preparations • Parenteral preparation 2) Targeted drug delivery system 3) Local delivery system
- 62. Prolonged release Oralpreparations Prodrugs Inactive form of the drug which undergoes biotransformation inside the body to pharmacologically active drug . They increase Absorption, distribution and duration of action.
- 63. ENTERIC COATED TABLETS& CAPSULES Drug coated with acid resistant substance 1. Prevent gastric irritation 2. Prevent alteration of drug in the stomach 3. To get desired conc. of drug in small intestine 4. Retards rate of absorption and prolongs duration of action
- 65. Controlled release /extended release / sustained release PREPARATIONS Release medication in a predetermined manner over extended period of time 1. Medicines incorporated in different layers 2. Granules of the drug 3. Medication can be covered with a gel which can swell and act like a semipermeable membrane
- 66. Prolonged Release Parenteralpreparations Pumps Osmotic pumps Portable pumps Computerised pumps Implantable pumps Pens Pellets Transdermal delivery system
- 67. PUMPS Deliver drugs ata predetermined rate for a specific period following a single application. MECHANICAL PUMPS Insulin infusion devices: -CSII-Continuous subcutaneous insulin infusion device Advantages: • More physiological & better control • Less variations in absorption
- 70. Insulin jet Deliversinsulin subcutaneously without using needle. Achieved by pressurizing the liquid through a small orifice which creates high speed jet that can penetrate the skin and underlying tissue
- 72. Dermojet It isa sub-cutaneous needleless injection used for mass inoculation
- 73. Pellet implantation Drug asa solid pellet is implanted under the skin to provide uniform systemic effect. • Eg: testosterone
- 74.
- 75. Transdermal Advantages • Slow effect(prolonged drug action) • First pass effect avoided Site – Upper arm, chest,abdomen, mastoid region
- 76. • This routeis most often used for the sustained delivery of drugs, such as the antianginal drug nitroglycerin, the antiemetic scopolamine. the nicotine patches. • Absorption- increase by oily base, occlusive dressing,rubbing preparation
- 78. • Transdermal patch •Scopolamine : Motion sickness Lasts 72hr, Applied 4hrs before journey Oral dose - action : 4-6hrs • Nitroglycerine : Angina – 1d • Clonidine : Hypertension – 7d • Nicotine : Smokers - 1 d • Fentanyl : Pain - 3 d
- 79. Local controlled deliverysystems OCULAR SYSTEMS Ocusert: Eg: Pilocarpine ocusert - Treatment of glaucoma Lasts 7 days Less side effects Dose also ↓
- 80. VAGINAL & UTERINESYSTEMS • Progestasert: Hormone releasing IUCD Release 60µg/d of progesterone for 1 year • Dinoprostone vaginal insert: Inserted vaginally Absorbs water swells and release drug - cervical ripening
- 81. IONTOPHORESIS Mild electriccurrent applied for the transport of drug across the skin Eg: Vasopressin, Dexamethasone
- 82. • Drug elutingstents: Stents can be coated with drugs embedded in a surface polymer
- 83. Targeted drug deliverysystems • LIPOSOMES Bilayered vesicles made of amphipathic phospholipids E g: Liposomal Amphotericin B
- 85. • Monoclonal antibodies• mAbs act directly when binding to a cancer specific antigen and induce immunological response to cancer cells
- 88.
- 89. •No single methodof drug administration is ideal for all drugs in all circumstances
- 90. Thanks to allParticipants in Teaching Learning Module PhD Scholar Dr Deepshika Yadav Dr Kopal Nimawat Dr Meenu Saharan PG Students Dr Shivankan Dr Retesh Dr Jaya Dadhich Faculty Dr Monica Jain Dr Alka Bansal Dr Uma advani Dr Charu Jain
- 91.