Novel Aspects of Polymer Use

& Processing

Contact Lenses & Ocular Drug

Delivery Systems

Polymers Are Omnipresent

• Automobiles

• Food & Beverage

• Energy – oil, solar panels, wind turbines

• Computers & Telecommunications

• Medical

• Pharmaceuticals

Polymers in Medical Devices

• Syringes, needles

• Bandages & Dressings

• Equipment

• Prosthetics – Artificial Limbs

• Implants – Heart valves, Dental Implants

• Drug Delivery

Ocular Medical Devices

• Contact Lenses

• Drug Delivery Systems

Contact Lenses

• Traditionally – Monomer Mix Heat Cast Rods

• Discs (Buttons) Cut

• Chucked & Lathed One Side

• Re-Chucked & Lathed Other Side

• Polished/Buffed

• Hydrated and Residual Monomers Extracted

• Labor Intensive & Scratch Marks Interfere

with Resolution – Less Visual Acuity

SpinCasting

• Highly Finished (Optical Surface)

• Monomer Mix Injected with UV Initiator

• Under Nitrogen Blanket – prevents “poisoning”

• Free Spin Surface Generated – Parabola

• Dynamic Equilibrium Established

• Polymerized by UV Lights

• Edges Finished

• Hydrated & Residual Monomers Extracted

• Sterilized & Vialed

Spincasting Process

Nitrogen

SpinCasting (Wichterle)

• Bausch & Lomb Acquired Rights

• 25cents + $1 for vial – Sold for $90/lens

• Lathed Lens Cost = $9.00/lens – Sold for $90

• B&L Allowed Competitors to Survive

• Johnson & Johnson Developed Cast Molding

CASTMOLDING

Cast Molded Contact Lenses

• One Mold Placed on Top of the Other

• Monomer Mix in Between

• Heat Initiated Polymerization

• Cost in Between Spinning & Lathing

• True Sphere Resulted in Superior Optics

• Better Resolution Than Parabola

• Superior Visual Acuity

Ocular Drug Delivery Systems

• Eye Maintains Homeostasis of 7.5 microliters

• Typical Drop Size is 50 microliters

• Excess Fluid Cleared from Eye

• Rolls down cheeks or flows down Naso-Lacrimal

Duct

• Severe Eye Infections – Patient Hospitalized

• Nurse Administers Medication every 5 mins!

Fig 1

Previous Attempts

• Gels – short lasting, interference with vision

• Creams – same as gels

• Contact Lenses Soaked in Drug Solutions – not

long lasting enough

• Lacrisert – Merck – dry eye interferes with vision

• Ocusert (Pilocarpine for Glaucoma) – Alza Corp.

– flat oval falls out during use

Requirements of Ocular Drug Delivery

Systems

• Sterility

• Comfort

• Versatility – long lasting/short lasting

• Non-Interference With Vision

• Oxygen Permeability

• Should not fall out of eye during use

Minidisc

• Cast Molded Shaped Concavo-Convex

• Mini “Contact Lens”

• Slightly Steeper Base Curve Against Eye –

slight suction

• Flexibility of Choice of Monomer Mix

allows Variable Physico-Chemical

Properties

• Hydrophobic to Hydrophilic Drugs

• Sterile – Gamma Irradiation

Constituents of the Minidisc

Figure 3

Distribution of Fluorescein in

Human Eye

In-Vitro Release Kinetics

In-Vivo Release Kinetics

Resolution of Eye Infection

Effect of Varying Acid Content

Mathematical Modelling

Implications For Ocular Health

• Many Eye Camps in India

• People from Rural Areas Transported

• Infection Rate Very High

• Have to be Retained in Clinic

• Interference with Life and Economic

Hardship

• Treat with Minidisc & Send Home

Questions??

General Entrepreneurship

Challenges

• Funding

• IP Protection

• Legal/SEC Compliance

• Personnel

• Cheaper Competition Global Marketplace – China & India

ADDITIONAL CHALLENGES IN

LIFESCIENCES• Regulatory Agencies – FDA/USDA

• Rigorous SOPs

• Stringent Quality Assurance Systems

• On-Going Training of Personnel

• Periodic On-Site Inspections

• Establishing Credibility as “Foreigner”

• Questionable Practices by Foreign Based

Firms

REGULATORY PROCESS

• PK/TK Studies

• Acute Toxicity (1 month)

• IND

• Chronic Toxicity (3,6,9 mths – 2 species)

• DART Studies for NCEs, Seg I, II, III

• NDA (New Drug Approval)

• Carcinogenicity Studies

REGULATORY PROCESS

(cont)

• Human Clinical Trials

• PHASE –I (normal volunteers)

• PHASE –II (diseased patients, single

center)

• PHASE –III (diseased patients, multi-

center)

• NDA APPROVAL

Cheaper Competition Global Marketplace –

China & India

• Language (China not India)!

• Unfamiliarity with Common Formulation

Practices

• Unethical Business Practices

• Studies Have to be Repeated in

Compliance with FDA Regulations

• Small Start-Ups Go Belly-Up!

Questions???

• THANK YOU VERY MUCH FOR

ATTENDING

• SURVEY TO PROVIDE FEEDBACK