Implants📱 Flashcards
(15 cards)
Definition
Devices or tissues inserted in or on the body (temporary or permanent).
Serve structural (e.g., prosthetics) or functional roles (e.g., drug delivery, monitoring).
Pharmacist’s Role
Understand drug interactions, mechanisms, and adverse effects.
Optimize therapy and counsel patients on medication-implant compatibility.
Example:
Avoid NSAIDs (e.g., ibuprofen) post-orthopedic implant due to impaired bone healing.
Avoid macrolides (e.g., erythromycin) in patients with pacemakers due to arrhythmia risk.
Ideal Properties of Implants
Biocompatibility: Minimal immune response & adverse effects.
East to sterilise: Must be sterile to prevent infection.
Biostability: Should remain stable in biological environments. Prevents degradation of implant.
Controlled/Sustained Release: Important for drug-delivery implants (e.g., drug-eluting stents).
Mechanical Strength & Flexibility: Especially critical for structural implants.Ideallu in the angle of strength/ stiffness of the tissue/organ where implant is inserted
Ease of Insertion & Removal
Advantages
Patient Compliance: Reduced need for daily dosing.
Convenience: Minimal maintenance.
Long-Lasting Therapy
Reduced Side Effects: Due to localized delivery.
Outpatient Use: Minimises hospital stays.
Improved Efficacy: Stable drug plasma levels.
Disadvantages
Surgical Insertion Required
Limited Drug Compatibility
Difficult Removal / specialist needed
Infection Risk
Adverse Reactions: E.g., immune or allergic responses.
Implant Failure: May require re-implantation / additional surgery to remove device
Classification by Purpose
Biostimulation Implants: Stimulates biological response. Eg promote tissue regeneration (e.g., bone grafts), dental implants to replace missing tooth roots & support dental crowns or bridges (endosteal implants), cartilage repair implants to support & end voyage cartilage regeneration in joints (meniscus implants)
Drug Delivery Implants: Hormonal (contraception, hormone replacement therapy) , pain management implants for pain relief directly to source of discomfort, insulin pumps
Neurostimulatory Implants: Deliver electrical signals (e.g., deep brain stimulators (DBS) for Parkinson’s / epilepsy by stimulating specific brain regions) , spinal cord stimulators (pain relief through electrical pulses to spinal cord) , vagus never stimulators (stimulate vagus nerve to treat epilepsy & depression)
Classification by Function
Orthopedic: Joint replacements, fracture fixation.
• Joint replacements: Replace damaged or diseased joints like hips, knees, and shoulders. (e.g.. Total hip replacements)
• Fracture fixation implants: Plates, screws, pins, and rods used to stabilize broken bones during healing.
(e.g. Locking bone plates)
• Arthrodesis implants: Facilitate joint fusion for conditions like severe arthritis. (e.g., Intervertebral body fusion cages)
Ophthalmic: Intraocular lenses, glaucoma shunts.
• Intraocular lenses (IOLs): Replace the natural lens of the eye after cataract surgery. (e.g., Monofocal
IOLS)
• Corneal Implants: Restore vision in patients with corneal damage. (e.g., Artificial corneas)
• Glaucoma drainage implants: Reduce intracular pressure in glaucoma patients. (e.g.. Trabeculectomy implants)
Cosmetic: Breast, facial, nasal implants.
• breast implants, chhance or reconstruct weast size and shape. eg sane or silicone set mplants)
• Facial implants: Improve facial contours like chin augmentation or cheek enhancement. (e.g., Silicone cheek implants)
• Rhinoplasty implants: Modify the shape of the nose. (e.g., Dorsal implants)
Classification by Material
Metals: Titanium, stainless steel.
Ceramics: Bone/teeth applications.
Polymers: Silicone, polyethylene.
Composites: Combine materials (e.g., metal-polymer joint replacements).
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Metals:
• Titanium and its alloys are strong, lightweight, and biocompatible, ideal for orthopaedic and dental implants.
• Stainless steel: Durable and corrosion-resistant, used in some orthopedic implants and surgical instruments.
• Cobalt-chromium alloys: High wear resistance, often used in joint replacements.
Ceramics:
• Alumina and zirconia: Biocompatible, wear-resistant, often used in joint replacements, especially bearing surfaces.
• Hydroxyapatite: Similar to the mineral component of bone, promotes bone growth and bonding, used in bone grafts and some dental implants.
Polymers:
Silicone: Flexible and biocompatible, used in breast implants, catheters, and drug delivery implants.
• Polyethylene: Wear-resistant and low friction, used in some joint replacements for gliding surfaces.
• Polyurethanes: Versatile with customisable properties, used in catheters, heart valves, and wound dressings.
Composites:
• Combine different materials for specific needs. Examples include metal-on-polymer bearings in joint replacements or carbon fibre-reinforced polymers for stronger bone plates.
Regulatory Classification
Class I: Low risk (e.g., sutures, bandages, external fixation devices). Generally exempt from premarket approval
Class II: Moderate risk (e.g., pacemakers, dental implants, catheters). Demonstration of safety and effectiveness
Class III: High risk (e.g., artificial heart valves, brain implants, spinal cord stimulators). Rigorous premarket testing & clinical trial. For safety and effectiveness.
Other classifications
Anatomy
Release mechanism
Fixation method
• By Anatomy: Implants can be categorized by the body part they are implanted in, such as cardiovascular implants or cochlear implants for the ear.
• By Release Mechanism: Drug delivery implants can be further classified based on how they release medication (passively, triggered by specific conditions, etc.).
• By Fixation Method: Implants can be cemented, press-fit, anchored with screws, or use a combination for secure placement within the body.
Non-biogradable
Drug-eluting stents
contraceptive rods/implants
titanium implants
pacemakers
vascular grafts
gastric stimulator
deep brains stimulators
Biodegradable
Eg OKD (in situ forming microparticles): PLGA + risperidone for schizophrenia.Semi solid. Solidifies body to release drug slowly. PGA slowly degrades
Bone scaffolds eg Osteocet: Calcium sulfate bone scaffolds. Inside bone. Promote bone healing.
Hydrogels: Can be stimuli-responsive (e.g., electric field-triggered drug release).
Physical Characteristics
Size: Micrometers (e.g., microparticles, PLGA microspheres like OKEDI) to >20 cm (e.g., hip titanium implants).
Shape: Fixed (eg contraceptive implant) or adjustable (eg bio-printed bone grafts)
Treatment/ Release Profile: Local or systemic.
Implantation Route: Injection or surgical (IM, IV, intrathecally, intracranially, intraperitoneally, etc.)
Controlled &sustauned release/ Duration of Action: Days to years.
Not examinable: Fabrication Methods (Most Common)
See camera roll tables
Summary
Implants enhance or replace biological functions.
Made from biocompatible materials via various fabrication methods.
Serve structural, regenerative, or drug delivery roles.
Pharmacists ensure compatibility and manage treatment. Adverse effects, provide counselling, monitor outcomes, collaborate with MDT
Advantages include improved function, quality of life, and durability.
Disadvantages may include infection risk, implant failure, and allergic reactions.
