ROUTES OF DRUG ADMINISTRATION AND DOSAGE FORMS.pptx

VARIOUS DRUG ADMINISTRATION AND DOSAGE FORM

1. ROUTES OF DRUG ADMINISTRATION AND DOSAGE FORMS

2. LOCAL Used for localised lesions at accessible site Systemic absorption-minimal Systemic side effect minimal 1/1/2003 96

3. LOCAL—TOPICAL Application of drug to the surface Over skin as ointment/ cream /lotion /paste /powder /spray Mucous membrane –dosage form depends on site of application 1/1/2003 97

4. Mucous membrane sites — dosage form Mouth &pharynx— paints,lozenges mouth wash,gargles Eyes-isotonic aqueous solutions ( sulfacetamide,gentamicin,ciprofloxacin , chloramphenical ) ear &nose – drops, ointment, nasal spray Git - non absorbable drugs eg-MgoH,sucralfate ,neomycin 1/1/2003 98

5. Bronchi & lungs—as inhalation , aerosol( nebulised soln. or powder) eg.salbutamol,cromolyn sodium Urethra-jellies eg.lignocaine Vagina - pessaries,vaginal tablets inserts,creams,powders , eg . anti fungals , metronidazole Anal canal—as ointment , suppositories , Enemata ( Evacuant enema,Retention enema) eg.dulcolax skin - Ionotophoresis , Jet injection Adhesive units, Inunction (rubbing drug on skin) 1/1/2003 99

6. Deeper tissues Intra articular injection eg.hydrocortisone Intra thecal injection eg.lignocaine Retrobulbar injection eg.hydrocortisone acetate 1/1/2003 100

7. Arterial supply Cancer chemotherapy Angiography 1/1/2003 101

8. Cutaneous—transdermal therapeutic system Slow & prolonged—liver bypassed 5-20 cm 2 – thro. Str. Corneum -diffusion Backing film-reservoir- micropore -adhesive with priming dose Rate of delivery < rate of absorption from skin 1/1/2003 102

9. Chest, abdomen, upper arm, lower back, gluteal , mastoid Eg.NTG , nicotine, estradiol , isosorbide , hyosine , clonidine … Adv; smooth plasma concentration, no first pass & side effects Disadv ; irritation , erythema . Future; timolol , insulin, digoxin , prostaglandin.. 1/1/2003 103

10. INHALATION Volatile liq / gases GA, amylnitrate Rapid absorption & elimination Irritant(ether) NASAL Liver bypassed Eg.posterior pituitary hormone, desmopressin , insulin,GnRH 1/1/2003 104

11. SYSTEMIC ROUTE Drug administered is intended to be absorbed into blood & distributed all over,including site of action,through circulation 1/1/2003 105

12. SYSTEMIC-ORAL MERITS commonest Cheaper No assistance needed DEMERITS Slow action Un palatable drugs Nausea vomiting Not used in unconscious patient Destroyed by gastric juices 1/1/2003 106

13. Oral dosage forms SOLID Powder Tablet Capsules Controlled Release - Spansules / timsules Moulded tab LIQUID Elixir Syrups Emulsions mixtures 1/1/2003 107

14. Enteric coated pills and tablets To prevent gastric irritation and alteration. To achieve the desired concentration of the drug in the small intestine; To retard the absorption of the drug.

15. SUBLINGUAL Lipid soluble/non irritant Liver bypassed Eg.NTG, isoprenaline , clonidine RECTAL Slow abs Ext. hemorroidal vein bypass liver Eg.aminophylline , indomethacin , paraldehyde, diazepam, ergotamine. 1/1/2003 109

16. PARENTERAL ROUTES ADVANTAGES Faster Unconscious Liver, intestinal mucosa bypassed cases of vomiting and diarrhoea . Drugs which might irritate the stomach not absorbed orally avoid drug modification by the alimentary juices and liver enzymes Rapid action and accuracy of dose are ensured. 1/1/2003 110

17. Disadvantages Less safe More expensive Inconvenient for use, self medication being difficult Liable to cause infection Likely to injure nerves and arteries

18. Injections Intradermal Subcutaneous Intramuscular Intravenous Intra-arterial Intrathecal Intraperitoneal Intramedullary Intra- articular & intra- lesional

19. SUBCUTANEOUS No irritants Absorption fast Avoided in shock A. dermojet B. pellet implantation C.sialistic implants INTRA MUSCULAR Absorption fast Mild irritants Depot preparation 1/1/2003 113

20. PARENTERAL ROUTES INTRA VENOUS Emergencies Aqueous only No depot F -100% Titration INTRA DERMAL BCG Sensitivity testing 1/1/2003 114

21. Irritants on IV administration Acidic, alkaline or hypertonic solutions Potassium and calcium solutions. Parenteral nutrition solutions. Aminophylline . Iron. Cancer chemotherapy agents Quinine, thiopental, phenytoin , diazepam, tetracycline, nitroglycerine, ethyl alcohol, radiocontrast media, propylene glycol, vasopressors .

22. Newer drug delivery system Ocusert Progestasert Liposomes Prodrug Computerised miniature pumps Monoclonal antibodies as drug carriers Dermojet Drug –eluting stents Pellets & biodegradable implants Gene Therapy

23. Ocusert thin elliptical microunits - contain the drug in a reservoir from which the drug is slowly released through a membrane by diffusion at a steady state. Eg : Pilocarpine ocusert – glaucoma - lower eyelid - 7 days. (No need to apply drops)

24. Progestasert This is an intrauterine contraceptive device - one year.

25. Liposomes Liposomes are minute vesicles produced by sonication of an aqueous suspension of certain phospholipids. They can be filled with non lipid soluble drugs, which are retained until the liposomes is disrupted. Eg : Amphotericin . B

26. PRODRUG inactive form of drug Eg : Dopamine does not cross the BBB but levodopa its prodrug can cross BBB . It provides longer duration of action.

27. Computerised miniature pumps These are programmed to release drugs at a definite rate Continuously in insulin intermittently in pulses GnRH

28. Monoclonal antibodies as drug carriers Usually an antigen has many antigenic determinants (called epitopes ) each of which gives rise to an antibody. Such antibodies are produced by different descendents of B lymphocytes (different clones of plasma cells) these antibodies are called polyclonal antibodies. In contrast to polyclonal antibodies, a monoclonal antibody reacts with a single antigenic determinant of any antigen

29. Mouse injected with Ag. having epitope a&b . B Hybridoma or Monoclonal BAntibody . produces B.lymphocytes each epitope B 1 B 2 B. lymphocyte fused with myeloma cell. (synthesis of monoclonal antibody)

30. If a mouse is immunised with an Ag. bearing two epitopes , it will produce B lymphocytes to each epitope . If such B lymphocyte are fused with constantly dividing cancer cells in polyethylene glycol, the resulting hybrid cells ( hybridomas ) will have an ability of the former to produce a single species of antibody and the capability of the latter to proliferate endlessly. The antibodies produced by these hybridomas are called as monoclonal antibodies. Such antibodies combine with just one antigenic determinant. Eg : transtuzumab , Rituximab .

31. Dermojet subcutaneous needleless injection of a drug by means of a high velocity jet projected through a microfine orifice. It is a painless procedure useful for mass inoculation.

32. Drug –eluting stents stents consists of metallic stent backbone covered with a polymer containing a drug ( sirolimus or paclitaxel ). The drug is released gradually over the next 14-30 days modifies the local healing response within the stented artery. used during coronary angioplasty. expensive reduced the incidence of restenosis

33. Pellets & biodegradable implants solid pellet or packed in biodegradable tubes is implanted under the skin to provide a uniform but a slow release of the drug lasting over months. Eg : testosterone & contraceptive implants

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