Eye Diseases and Pharmacology

Questions and Answers

100-640 mOsm/kg

231-446 mOsm/kg (correct)

Less than 100 mOsm/kg or greater than 640 mOsm/kg

Greater than 640 mOsm/kg or less than 231 mOsm/kg

To enhance the irritation consequences of the nanosystem

To increase the frequency of doses

To reduce the frequency of doses and improve drug bioavailability (correct)

To reduce the bioavailability of the drug

In vivo tests

Ex vivo tests

Visual inspection (correct)

In vitro tests

<p>To demonstrate the ability of the nanosystem to penetrate through the cornea</p> Signup and view all the answers

<p>Fluid evaporation</p> Signup and view all the answers

Study Notes

Conjunctiva, AMD, diabetic retinopathy, and retinoblastoma represent conditions with varying effects on drug absorption, notably less impactful compared to the cornea.
Certain macromolecular nanomedicines, peptides, and oligonucleotides can penetrate deeply into the eye through conjunctiva.
Blood-ocular barriers, which include the blood-aqueous barrier (BAB) and blood-retinal barrier (BRB), limit the passage of xenobiotic compounds into the bloodstream.

Ocular formulations can be delivered via topical, intraocular, and periocular routes, or through ocular devices.
Dosage forms include liquid, semi-solid (ointments and gels), solid (powders and inserts), or mixed (in situ gels).
Most marketed ocular products (over 95%) are in liquid form.

Significant challenges include precorneal, corneal, and blood-corneal barriers that impede effective drug penetration.
Prolonging drug residence time and ensuring proper ocular permeation have been ongoing scientific pursuits.

Nanotechnology is becoming increasingly appealing for ocular drug delivery due to its ability to encapsulate both hydrophilic and lipophilic drugs.
Advantages of nanocarriers include enhanced ocular permeability, increased drug stability, sustained residence time, and improved bioavailability.

Various in vitro, ex vivo, and in vivo characterization techniques help predict the performance of nanocarriers in drug delivery.
Common in vivo models include rodents (rabbit, rat, mouse), while in vitro models utilize epithelial cells, reconstructed corneas, or excised corneas along with permeation chambers (Franz-type diffusion cell).

Ocular retention is critical as it minimizes dosing frequency and enhances bioavailability of ophthalmic drugs.

Ocular preparations with osmolality lower than 100 mOsm/kg or greater than 640 mOsm/kg are considered irritants.
The normal range for osmolality in open eyes is between 231 to 446 mOsm/kg, restored shortly (within minutes) after administration of non-isotonic solutions.