- Biopharmaceutics is the study of how a drug's physicochemical properties affect its biological availability and action in the body. Pharmacokinetics is the study of a drug's absorption, distribution, metabolism and excretion within the body over time. - Common routes of drug administration include oral, buccal, rectal, topical, and intravenous. The oral route is the most common due to convenience but has disadvantages like variable absorption. The intravenous route has 100% bioavailability but is more invasive. - The route of administration impacts the drug's pharmacokinetics by influencing factors like absorption, distribution, metabolism and excretion - which determine the drug's onset, duration and intensity of effects.

1. INTRODUCTIONOFBIOPHARMACEUTICSANDPHARMACOKINETICS
ROUTESOFDRUGADMINISTRATION
BPS 15

2. INTRODUCTION OF BIOPHARMACEUTICS
AND PHARMACOKINETICS
◦ Biopharmaceutics is the study of the physical and chemical properties of drugs
and their proper dosage as they relate to the onset, duration, and intensity of drug
action
◦ Other definition , the study of the effects of physicochemical properties of the
drug and the drug product, in vitro, on the bioavailability of the drug, in vivo, to
produce a desired therapeutic effect.

3. ◦ Pharmacokinetics is the study of a drug's time course inside the body (the
amount and duration of systemic exposure to the drug) as well as the process of
the drug's absorption, distribution, metabolism, and excretion (ADME) pattern
◦ PROCESS OF PHARMACOKINETICS :
Absorption
Distributions
Elimination (Clearance) -Cl

4. ORAL ROUTE ADMINISTRATION
◦ Most small molecule drugs are taken orally and ingested.Oral ingestion is the oldest and most common mode of drug
administration.Both solid dosage and liquid dosage forms
Absorption of enterally administered drugs is determined, in part, by the physiological state is affected
◦ Diet
◦ Hormones
◦ autonomic nervous system
◦ disease states
◦ other drugs.

5. a. Advantages
• It is convenient
• Its absorption
• It is cheap
b. Limitations
• slower and therefore unsuitable for
emergencies.
• Unpleasant drugs are difficult to
administer
• May cause nausea and vomiting
(emetine).
• Uncooperative /unconscious / vomiting
patients.
• Drug absorption can be variable and
irregular
• Others are destroyed by digestive
juices or by the liver

6. Pharmacokinetics Significance
Absorption-promoting
factors include high lipid
solubility and low ionization.
Milk, fetus, and most "third
spaces" have acidic pH
values (7.0) compared to
plasma (7.4).
Some drugs, such as highly lipid-
soluble drugs, are so highly
metabolized that on ‘the first
pass through the liver there is
substantial ‘pre-systemic’
elimination.
If the drug is in a union, there is the
reabsorption of the renal tubular
lumen in the blood state, therefore,
reabsorption will occur in acidic
urine, while elimination will occur in
alkaline urine.
The maximum plasma concentration is represented
as Cmax, and the time had to reach maximum
concentration is represented as tmax.
Absorption
Distribution
Metabolism
Elimination

7. INTRODUCTION BUCCAL ROUTE
◦ The buccal mucosa is the lining of the cheeks and the back of the lips within the mouth.
◦ The buccal route of drug administration is where the dosage form is placed between your gums and cheek.
◦ The drug will be absorbed by buccal mucosa.

8. PHARMACOKINETIC OF BUCCAL ROUTE
◦ Drugs absorbed via the buccal mucosa penetrate directly into the systemic circulation.
◦ It is distributed directly to the affected area.
◦ It bypasses the gastrointestinal tract and first-pass metabolism in the liver.

9. ADVANTAGE
◦ Avoiding First Pass Metabolism.
◦ Avoiding destruction of the drug by GI acidity.
◦ Rapid Absorption.
◦ Provides a steady infusion of a drug over an extended period of time.
◦ Administered to unconscious or wounded patients.
◦ Only focused on the mouth cavity.
◦ Suitable for drugs that are unstable in the acidic environment.

10. LIMITATION
◦ Not all drugs can efficiently pass the mucosal epithelium.
◦ Not suitable for people who are nauseous or vomiting.
◦ Drug absorption is difficult in people with dry mouths.
◦ Possibility of choking.
◦ Cannot be applied if the drugs are unstable at the pH of the buccal cavity.
◦ Irritate the buccal mucosa.
◦ Has unpleasant taste or an unpleasant odour.

11. RECTAL ROUTE OF ADMINISTRATION
◦ Rectal route can be used as a drug delivery route for both local and systemic effects. It offers a faster, safer, and low cost route of
administration when compared to several other alternative routes. The dosage forms of the rectal route of administration include
suppositories and enemas.

12. ADVANTAGES
◦ Applicable in cases of nausea, vomiting, and inability to swallow (unconscious patients), as well as in the presence of diseases of the upper
gastrointestinal tract that affect oral drug absorption.
◦ Avoids the contact of the drug with the aggressive conditions of the upper gastrointestinal tract.
◦ Suitable for formulations with unpleasant taste.
◦ The absorption rate of the drug is not influenced by food or gastric emptying.
◦ Part of the metabolism of both enteric and first-pass hepatic elimination is avoided
◦ Preferred route when drugs are administered to relieve constipation or hemorrhoids.

13. LIMITATIONS
◦ Possible complication of local irritation.
◦ The interruption of the absorption process by defecation
◦ Absorption can be highly irregular and incomplete.
◦ The reduced surface area may limit absorption, in the same way that the low volume of rectal fluids can lead to incomplete dissolution
of the drug.
◦ Possible degradation of certain drugs by microorganisms in the rectum.
◦ Patient adherence may be a problem.

14. PHARMACOKINETICS SIGNIFICANCE
◦ Drug is absorbed in the lower part of the rectum and delivered directly into systemic circulation, thus avoiding any first-pass
metabolism.

15. TOPICAL ROUTE ADMINISTRATION
 A topical drug delivery system is a way to deliver medication that is applied onto
a particular part of the body, typically the skin, to treat various ailments.
 The intent of containing the pharmacological effect of the drug only to the
surface or within the layers of skin or mucous membrane.
 Topical route of administration provides a high local concentration of the drug
without affecting the general circulation.

17. PHARMACOKINETIC SIGNIFICANCE
Absorption : It is influence drug effectiveness and safety. Bioavailability after
intramuscular (IM) and percutaneous (topical) administration can be affected by tissue
mass, perfusion, drug permeability, and surface area. In neonates, reduced muscle
perfusion and contractility can limit absorption after IM administration.
Metabolism : For the topical drug delivery way, degradation of drugs in skin is very low
compared to liver. The metabolism of drugs is mainly by metabolic enzyme cytochrome
P450, and this enzyme is not active in skin. The CYP450 actively metabolized drugs can
then maintain high concentration when being applied on skin.
Distribution : Once in the circulation, the drug is transferred to the interstitial fluid and to
the cells of the body.

18. Transdermal Route of administration
• Transdermal also known as patches.
• The medicine is applied in the form of a patch, which allows the drug to enter the bloodstream and have a
systemic impact.
• Transdermal patches (TDP) are divided into three categories:
 Matrix
 Reservoir
 Drug-in-adhesive
• The skin's thick and lipid-rich outer layer, known as the stratum corneum (SC)
• Transdermal patches usually last for 1 to 3 days
• Applied anywhere over the body, chest, abdomen, upper arm, lower back, buttock.

21. Pharmacokinetic significance
 Absorption: It absorbed by the skin and into the bloodstream. When drug reaches the dermal
layer, it becomes available for systemic absorption via the dermal microcirculation
 Distribution: The drug initially penetrates through the stratum corneum and then passes through
the deeper epidermis and dermis without drug accumulation in the dermal layer.
 Metabolism: The active enzyme in viable skin tissues have a capacity for bio-transforming
topically applied compounds, with a consequence of an altered pharmacological effect.
 Elimination: Transdermal drugs bypass the digestive system and enter the bloodstream at a
controlled rate regulated by the skin.

22. INTRAVENOUS ROUTE(IV) OF
ADMINISTRATION
◦ Intravenous (IV) drug administration is injecting a drug solution directly into the bloodstream
through a vein.
◦ It is the most efficient and accurate approach to deliver a dose since the drug enters systemic
circulation without the delay.
◦ This route has a 100% bioavailability.
◦ There are two types of IV route ;- IV bolus, IV diffusion

24. Pharmacokinetic (ADME) for IV route