Drug selection criteria for different drug delivery system for selection of appropriate drug is targeted at particular drug delivery system.

1. Mr. Sagar Kishor Savale
[Department of Pharmaceutics]
avengersagar16@gmail.com
2016-2017
Department of Pharmacy (Pharmaceutics) | Sagar savale
Drug Selection Criteria For Different Drug
Delivery Systems

2. 13-Aug-162
Drug delivery is the method or process of administering a pharmaceutical compound to achieve a
therapeutic effect in humans or animals.
The method by which a drug is delivered can have a significant effect on its efficacy.
Some drugs have an optimum concentration range within which maximum benefit is derived, and
concentrations above or below this range can be toxic or produce no therapeutic benefit at all.
On the other hand, the very slow progress in the efficacy of the treatment of severe diseases, has
suggested a growing need for a multidisciplinary approach to the delivery of therapeutics to targets in
tissues.
From this, new ideas on controlling the pharmacokinetics, pharmacodynamics, non-specific toxicity,
immunogenicity, bio recognition, and efficacy of drugs were generated.
These new strategies are called drug delivery systems (DDS). To minimize drug degradation and loss, to
prevent harmful side-effects and to increase drug bioavailability and the fraction of the drug accumulated in
the required zone, various drug delivery and drug targeting systems are currently under development.

3. 13-Aug-163
 Oral drug delivery systems.
 Parenteral drug delivery systems.
 Mucosal drug delivery systems.
 Nasal drug delivery systems.
 Pulmonary drug delivery systems.
 Ocular drug delivery systems.
 Transdermal drug delivery systems.
 Vaginal & intrauterine drug delivery systems.
 Rectal drug delivery systems.
 Targeted drug delivery systems.

4. 13-Aug-164
ORAL DRUG DELIVERY SYSTEMS
Oral administration of drugs is the simplest, easiest and most common route of
administration. After absorption from the GIT, the drugs can be metabolically
deactivated unless special measures are taken to protect them. Then the drug
enters the systemic circulation and is distributed to the target and other tissues.
The existence of first pass metabolism is the most significant challenge and
disadvantage of oral drug delivery. This route is not suitable for the systemic
delivery of drugs that are poorly absorbed or destroyed in the GIT.
The most commonly used dosage forms for oral delivery of drugs are solids,
liquids and disperse systems. Liquid systems include oral solutions. Disperse
systems include suspensions and emulsions. Solid dosage forms include a wide
variety of tablets, capsules, caplets and powders.

5. 13-Aug-165
DRUG SELECTION CRITERIA
 Drugs with molecular weight/size < 1000 Da.
 Drug solubility should be greater than 0.1μg/ml.
 Drugs with high permeability should be selected, as matrix tablets are release rate
limiting but not permeation rate limited.
 A drug that is passively absorbed through the GIT is an ideal candidate for sustained
release matrix tablets.
 Drugs which exhibit absorption window due to site specific or active transport
processes are poor candidates as they may have incomplete bioavailability. Ex:
Riboflavin, folic acid, aminopenicillins and nucleoside analogues.
 Drugs with low half-life.
 Drugs with larger therapeutic window.
 The drug should not be influenced by pH and enzymes.

6. 13-Aug-166
ORAL DISPERSIBLE SYSTEM
Drug Selection Criteria
 The drug should not have a bitter taste.
 The dose should be lower than 20 mg.
 The drug should have moderate to low molecular weight.
 It should have good stability in water and saliva.
 The drug must be partially non-ionized at the oral cavities pH.
 It should have the ability to diffuse and partition into the epithelium of upper GIT.
 It should have the ability to permeate oral mucosal tissue.
 Drugs with shorter half-lives are unsuitable to be formulated as ODTs

7. 13-Aug-167
PULSATILE DRUG DELIVERY SYSTEMS
Drug Selection Criteria
 Chronopharmacotherapy of diseases which show circadian rhythms in their
pathophysiology.
 Drugs which show extensive first pass metabolism. Ex. β blockers and
salicylamide.
 Drugs which undergo extensive first pass metabolism require fast drug input to
saturate metabolizing enzymes in order to minimize pre-systemic metabolism.
 Drugs having short half-lives like β blockers.
 Drugs which show biological tolerance like transdermal nitro-glycerine and
Salbutamol sulfate.
 Drugs needed to be targeted to the specific site in the intestine.
 Drugs which cause gastric irritation (NSAIDS) and for the drugs which are not
stable in GI fluids like proteins.

8. 13-Aug-168
COLON TARGETED DRUG DELIVERY
Drug Selection Criteria
 Drugs which show poor absorption from stomach or intestine are the best
candidates.
 Peptides, proteins, oligonucleotides and vaccines are potential candidates for colon
targeted DDS.
 Drugs used in the treatment of inflammatory bowel disease, ulcerative colitis,
diarrhoea and colon cancer are ideal candidates.
 Drug carrier is another factor which influences Colon targeted DDS. The selection of
carrier for particular drugs depends on the physiochemical nature of the drug as well
as the disease for which the system is to be used.
 Factors such as chemical nature, stability and partition coefficient of the drug and
type of absorption enhancer chosen influence the carrier selection. Moreover, the
choice of drug carrier depends on the functional groups of the drug molecule.

9. 13-Aug-169
FLOATING DRUG DELIVERY SYSTEM
Drug Selection Criteria
 Drugs with narrow absorption window in stomach. E.g. Riboflavin and Levodopa.
 Drugs which are basically absorbed from the stomach and upper part of GIT. E.g.
Chlordiazepoxide and Cinnarazine.
 Drugs that disturb normal colonic bacteria. E.g. Amoxicillin trihydrate.
 Drugs which are locally active in stomach. E.g. Antacids and Misoprostol.
 Drugs that degrade in the colon. E.g. Ranitidine HCl and Metronidazole.
 Drugs that have poor bioavailability because of site-specific absorption from the
upper part of GIT are potential candidates to be formulated as FDDS, thereby
maximizing their absorption.

10. 13-Aug-1610
TRANSDERMAL DRUG DELIVERY SYSTEMS
Drug Selection Criteria
 Dose should be low i.e. < 20mg/day.
 Half life should be 10h or less.
 Molecular weight should be <400 Da.
 Partition coefficient Log Po/w should be between 1.0 and 4.
 Skin permeability coefficient should be 0.5x10-3 cm/h.
 Drug should be non-irritating and non-sensitizing to the skin.
 Oral bioavailability should be low.
 Therapeutic index should be low.

11. 13-Aug-1611
MUCOADHESIVE DRUG DELIVERY SYSTEMS
Drug Selection Criteria
 Drugs with less elimination half-life.
 Drugs which have poor bioavailability.
 Drugs which require frequent dosing.
 Drugs which show local action in the oral mucosa.

12. 13-Aug-1612
VESICULAR DRUG DELIVERY SYSTEMS
Drug Selection Criteria
 Drugs which have low bioavailability and varied pharmacokinetics.
 Drugs which are poorly soluble.
 Drugs with short half-life.
 Drugs which require prolonged residence time in blood can be given as the vesicular
preparations
 prolong the residence time.
 Drugs which require specific targeting. For example liver targeting can be done as their small
size aids in RES uptake and they can be used to target the cancerous tissue.
 As vesicles aid in dermal/transdermal delivery drugs which require dermal/transdermal
delivery can be selected.
 Only potent drugs can be selected.

13. 13-Aug-1613