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Pharmaceutics 2 Winter Final > 2 - Nasal > Flashcards

2 - Nasal Flashcards

1
Q

Nasal cavity has ____ vascularity

A

Rich

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2
Q

What is beneficial about nasal cavity w/ respect to bioavailability?

A

Topical administration provides rapid blood levels comparable to IV route

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3
Q

How can be drugs administered topically to the nasal cavity?

A

Drug solution as a fine mist, which adheres to mucosa as a thin film

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4
Q

Why shouldn’t large droplets be applied to the nasal cavity?

A

Will coalesce and run off instead of be absorbed

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5
Q

What are advantages to nasal drug delivery?

A
  • Rich vascularity provides direct route into bloodstream from drugs that easily cross mucous membranes
  • Avoids GI exposure and hepatic first pass metabolism
  • For some drugs, rate of absorption is comparable to parenteral administration, and often better than SC or IM
  • Intranasal administration has easy access, is painless, and convenient
  • Nasal mucosa close to brain, and in some situations may provide access to CSF
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6
Q

What are some limitations to the intranasal route?

A
  • Absorption area limited, so only compounds w/ high potency and small therapeutic dose can be administered
  • Damage or irritation to nasal mucosa from colds/allergy will affect residence time and absorption
  • Mucociliary clearance is a big factor; drug may be carried away before it can be absorbed
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7
Q

Which drug delivery systems are classified as alternative routes?

A
  • Buccal
  • Sublingual
  • Nasal
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8
Q

What is nasal drug delivery mainly used for?

A

Local therapeutic treatments, like allergic rhinitis, common cold, and nasal inflammation

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9
Q

Nasal drug delivery is being actively researched for possibility of delivering _____ drug

A

Protein and peptide

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10
Q

What do decongestant nasal sprays do?

A

Constrict blood vessels in lining of nose and open up nasal passages

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11
Q

What can prolonged decongestant use cause?

A
  • Damage to mucous membranes
  • Increased inflammation
  • Called rhinitis medicamentosa (RM) or rebound effect
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12
Q

What are some decongestant drugs?

A
  • Phenylephrine
  • Oxymetazoline
  • Ipratropium
  • Tetrahydrozoline
  • Azelastine
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13
Q

How do antihistamines work in the nasal cavity?

A

Compete for receptor sites to block function of histamine, thereby reducing inflammatory effect

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14
Q

What are some antihistamine nasal sprays?

A
  • Azelastine
  • Levocabastine
  • Olopatadine
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15
Q

What are intranasal corticosteroids used for?

A

Sinusitis, hay fever, allergic rhinitis, and non-allergic rhinitis

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16
Q

What do corticosteroids do in the nasal cavity?

A
  • Reduce inflammation and histamine production in nasal passages
  • Relieve nasal congestion, runny nose, itchy nose, and sneezing
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17
Q

What are some intranasal corticosteroids?

A
  • Beclomethasone
  • Budesonide
  • Ciclesonide
  • Flunisolide
  • Fluticasone
  • Mometasone
  • Triamcinolone
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18
Q

Which vaccine is available as a nasal spray?

A

LAIV (live attenuated influenza vaccine)

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19
Q

What must happen for drugs delivered intranasally to have a systemic effect?

A

Must pass through nasal mucosa layer and then the epithelial layer

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20
Q

How is passage of drugs across nasal mucosa achieved?

A
  • Paracellular passage – between cells through tight junctions; main pathway for polar drugs w/ low MW
  • Transcellular passage – passive diffusion through cells; major pathway in absorption of lipophilic drugs
  • Facilitated diffusion – diffusion helped by protein channels; no energy expenditure
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21
Q

Can drugs be actively transported across nasal mucosa?

A

Yes

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22
Q

What is transcytosis?

A

When particles and macromolecules are taken inside a vesicle and passed through the cell

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23
Q

____ molecules are absorbed rapidly across the nasal mucosa

A

Lipophilic

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24
Q

____ molecules generally have poor absorption across nasal mucosa. How can absorption of these drugs be increased?

A
  • Low MW hydrophilic

- Can increase absorption by adding absorption enhancers to the formulation

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25
Q

Do anti-migraine drugs require absorption enhancers when given intranasally?

A

No, they are sufficiently lipophilic to cross nasal mucosa in high enough quantities to meet desired therapeutic effect

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26
Q

Which anti-migraine drugs are given intranasally and how?

A
  • Sumatriptan delivered as a powder form

- Dihydroergotamine (antihistamine for nausea associated w/ migraines) delivered as a spray

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27
Q

Which peptide drugs are given intranasally? What are they used for?

A
  • Hormone treatments
  • Desmopressin (for diabetes insipidus)
  • Oxytocin (increase duration and strength of contractions during labour)
  • Calcitonin-salon (treat hypercalcemia)
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28
Q

Do peptide drugs require absorption enhancers when given intranasally?

A

No b/c highly potent so only require a bioavailability around 2-3% to show therapeutic efficacy

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29
Q

What are some other miscellaneous drugs given intranasally and for what conditions?

A
  • Midazolam (acute episodes of seizures in children)
  • Naloxone (opioid overdoses)
  • Ketorolac (NSAID for pain relief)
  • Ketamine (investigated for breakthrough pain management)
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30
Q

What are the types of packaging of intranasal medications?

A
  • Meter-dose
  • Plastic spray bottles
  • Dropper (very uncommon now)
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31
Q

What function of the nose impacts nasal drug delivery and absorption?

A
  • Nose or URT modifies inspired air by filtration, humidification and warming
  • To do this, nose must control rate of air flow, remove noxious agents, and introduce large quantities of fluid into air stream
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32
Q

What are the functional zones in the nasal cavity?

A

1) Vestibular – surface covered by epithelium w/ long hairs to filter out all airborne particles
2) Respiratory – surface normally covered by dense layer of mucous; mucous constantly moving toward posterior apertures of nasal cavity by system of motile cilia
3) Olfactory – above middle turbinate; generally free of inspiratory air flow

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33
Q

What covers a normal mucosa?

A

Mucous secreted from various nasal glands

34
Q

Nasal mucous is renewed about every ____

A

10 minutes

35
Q

How much mucous is produced daily? What does it contain?

A
  • About 1.5-2 L produced daily

- Contains 90-95% water, 1-2% salts, and 2-3% mucin

36
Q

What is the normal surface area of nasal mucosa in an adult?

A

150-200 cm^2

37
Q

What is the most important defense mechanism of the respiratory tract?

A
  • Nasal mucociliary clearance, which carries airway secretions backward to nasopharynx and stomach through swallowing
  • In the anterior nares, mucociliary clearance moves forward to provide clearance by nose blowing or wiping
38
Q

What is the average rate and transit time of nasal clearance?

A
  • Average rate = 6-8 mm/min

- Transit time = 12-15 minutes

39
Q

What effect does nasal mucociliary clearance have on drug delivery? How can this be changed?

A
  • Could lead to drug loss if the product isn’t formulated correctly
  • Can add an excipient to enhance residence time on mucosa
40
Q

What is the normal pH of adult nasal secretions? When does this change?

A
  • 5.5-6.5
  • Can lean on alkaline side during allergic rhinitis, acute sinusitis, and acute rhinitis
  • Can be altered by heat or cold (cold air produces drift towards alkalinity and heat yields drift toward acidity)
  • pH also varies w/ sleep, rest, food ingestion, emotion, and infection
41
Q

What can happen if nasally administered medications contact olfactory mucosa?

A
  • Molecular transport can occur directly across the tissue and into CSF
  • Mucosa can transport directly into the brain, skipping the BBB potentially achieving CSF levels higher and faster than IV administration
  • This is called the nose-brain pathway; good for sedatives, anti-seizure drugs, and opiates
42
Q

What must be considered when using the nasal route for drug administration?

A

That some CNS absorption may occur

43
Q

Which viral diseases can enter the body through the nasopharynx?

A

Measles, common cold, and chicken pox

44
Q

What should be done for nasal doses?

A

Should be divided in half w/ each nostril receiving half the dose to double the absorptive surface area

45
Q

A ______ gives a very good nasal mucosa distribution

A

Atomized pump delivery system

46
Q

What is the ideal particle size for the nasal mucosa?

A
  • 10-20 um are deposited on nasal mucosa

- Less than 2 um pass through and deposit into lungs

47
Q

What happens if drugs are introduced into the nasal mucosa as soluble particles?

A

They readily dissolve into nasal lining secretions and then are absorbed into blood

48
Q

_____ of the drug are the most important parameters in dosage form design

A

Physicochemical properties

49
Q

What is the ideal molecular weight for paracellular absorption?

A

Under 300

50
Q

What is the maximum volume that can disperse onto nasal mucosa? What happens if more than this is administered?

A

0.5 mL; excess will run off mucosa into the throat or out of nostril and be lost

51
Q

What is the ideal volume for one nostril?

A

0.25-0.3 mL

52
Q

What will cause reduced effect of nasal drugs?

A

Px w/ bloody noses or high mucous production in nasal cavity

53
Q

When are absorption enhancers used for nasal drugs?

A
  • Small hydrophilic drugs
  • Peptides, proteins, nucleic acids
  • Polysaccharides
54
Q

Which molecules are more affected by mucociliary clearance?

A

Polar molecules which are more slowly absorbed across nasal mucosa

55
Q

What are mucoadhesive agents?

A

Hydrocolloids that can form weak covalent, ionic, and H bonds w/ mucous and slow mucociliary clearance

56
Q

What do mucoadhesive agents do?

A

Increase viscosity to increase residence time that drug is in contact w/ nasal mucosa

57
Q

What are some examples of mucoadhesive agents?

A
  • Carbopol
  • Chitosan
  • Sodium carboxymethylcelluose
  • Polyacrylic caids
  • Hydroxypropyl methylcellulose
  • Hydroxypropyl cellulose
58
Q

What does nasal mucous contain? How does this react for mucoadhesive agents?

A
  • Anionic and contains more sulfate groups
  • Polymers are able to interact electronically or H-bond (anionic polymers like carbopol and HMPC can form H-bonds; cationic polymers like chitosan can interact ionically)
59
Q

Why is poloxamer 407 a bad mucoadhesive agent? How can it be improved?

A
  • Forms a gel at body temp in the nose
  • Non-ionic
  • Can be improved by addition of a polymer
60
Q

What are some properties involved in selecting a polymer for bioadhesion?

A
  • Molecular weight
  • Concentration
  • Hydrophobicity
  • Ionic charge
  • Degree of cross-linking
61
Q

How can some polymers affect ciliary beat frequency?

A
  • Ciliary beating requires calcium ions

- Acrylic acids complex calcium, slowing down beat frequency and mucociliary clearance

62
Q

What can happen w/ chronic use of mucoadhesive agents?

A
  • Reduce effectiveness of mucociliary clearance as a defensive process
  • Could allow inhaled microorganisms the opportunity to grow and cause local and respiratory infections
63
Q

What are absorption promoters?

A

Agents that increase permeation of drugs across the mucosa by disrupting nasal epithelium (usually surfactants)

64
Q

Which molecules are used as absorption promoters? What is a disadvantage to these?

A
  • Laureth-9, bile acids, and bile acid derivatives; chitosan is also an absorption promoter through regulating tight junctions in cell membrane
  • Irritate the nasal mucosa, so must weigh risk vs. benefit
65
Q

What are some drugs that show enhanced absorption when administered w/ an absorption promoter?

A
  • Budesonide
  • Caffeine
  • Ketorolac
  • Metoprolol
  • Midazolam
  • Nicotine
  • Tobramycin, gentamicin, vancomycin
66
Q

What happens when a drug is given nasally as a powder?

A

Tends to slow mucociliary clearance and absorb water at tight junctions between cells

67
Q

Formulations of drugs w/ chitosan showed better absorption as ____ than ____, but may cause ______

A
  • Better absorption as powders than solutions

- May cause irritation w/ prolonged use

68
Q

How should a drug be formulated to encourage prolonged residence time?

A

Isotonic and have pH around 7.4

69
Q

Drugs should be in _____ state for maximum absorption

A

Unionized (so should be below 5.5 or above 6.5)

70
Q

What is the pH of nasal secretions?

A

5.5-6.5

71
Q

What must be considered since nasal drugs may be delivered to the lungs?

A
  • Must consider microbial quality of the product

- Multi-dose products should contain a preservative

72
Q

What droplet size is optimal for deposition on nasal mucosa?

A

5-7 um

73
Q

What should be considered when choosing a nasal device?

A
  • Droplet size
  • Spray pattern
  • Nature of formulation
74
Q

What are nano- and micro-particulate systems?

A

Matrix systems where drug is dispersed in polymeric material

75
Q

How is drug loaded into a nano- or micro-particulate system?

A

Through incorporation w/ the system or adsorption on particulate system

76
Q

How is drug released from particles in a nano- or micro-particulate system?

A
  • Release from particle surface
  • Diffusion of drug from swollen polymer matrix
  • Drug release through erosion of polymers
77
Q

What is important about nano- and micro-particulate systems?

A

Have mucoadhesive properties to aid in retention and action in nasal mucosa

78
Q

What are some properties of chitosan?

A
  • Cationic polymer w/ strong mucoadhesive properties

- Also enhances penetration through its ability to transiently open tight junctions in nasal mucosa

79
Q

How is mucoadhesion achieved w/ chitosan?

A

Ionic interaction of positively charged amine groups of D-glucosamine units of chitosan w/ negatively charged sialic acid groups of mucin or other negatively charged groups of mucosal membrane

80
Q

What determines the systemic bioavailability of intranasal corticosteroids?

A
  • Sum of nasal and intestinal absorption

- Clearance by first-pass hepatic metabolism

Pharmaceutics 2 Winter Final (9 decks)

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