Nitroglycerin is effective as sublingual medication because it is:
Ans. c. Non-ionic and highly lipid soluble (Ref: Goodman Gillman 12/e p22: KDT e p6)Nitroglycerine is effective as sublingual medication because it is non-ionic and highly lipid soluble."Sublingual Administration. Absorption from the oral mucosa has special significance for certain drags despite the fact that the surface area available is small. Venous drainage from the mouth is to the superior vena cava, bypassing the portal circulation and thereby protecting the drug from rapid intestinal and hepatic first-pass metabolism. For example, nitroglycerin is effective when retained sublingually because it is non-ionic and has very high lipid solubility. Thus, the drug is absorbed very rapidly. Nitroglycerin also is very potent: absorption of a relatively small amount produces the therapeutic effect. "--Goodman Gillman 12/e p22Systemic Routes of Drug Administration1. Oral* Most common & most convenient2. Sublingual* Avoid first pass metabolism, used in emergencies* Drug should be nonionic having very high lipid solubilityQ* Example: Nitroglycerine, Isosorbide dinitrate & Nifedipine3. Rectal* Drug is absorbed into external hemorrhoidal veins, bypasses liver, but not that absorbed into internal hemorrhoidal veins.* First pass metabolism occurs, but less than oral route (Avoid first pass metabolism by 50%)* Example: Diazepam in children for febrile seizures4. Cutaneous* Transdermal for highly lipid soluble drugs* Example: Nitroglycerine. Nicotine, Hyoscine, Fentanyl & Estrogen5. inhalational* Drug delivery can be controlled like IV infusion* Drugs used in asthma: Salbutamol, Ipratropium, Monteleukast, Inhalational steroids& Inhalational anesthetics6. Nasal* Example: Nafarelin (GnRH agonist), Calcitonin, Desmopressin, Influenza vaccine7. ParenteralIntravenous* Emergency use, increased risk of adverse effect, not suitable of oily solutions, or poorly soluble substance best for steady state plasma concentration.Subcutaneous* Suitable for some poorly soluble suspensions, appropriate for self administration (Example: Insulin)Intradermal* The drug is injected into skin raising a bleb (e.g. BCG vaccine, sensitivity testing).* It produces local tissue necrosis and irritationIntramuscular* Suitable for oily solutions and some irritating substancesNanotherapyNanotherapy: Novel method for drug deliveryNanoparticles are offering new opportunities for diagnosis, targeted drug delivery and imaging of clinical effect
Ionic and lipid soluble
Ionic and less lipid soluble
Nonionic and highly lipid soluble
Nonionic and less lipid soluble
Pharmacokinetics