Nanoparticles in Drug Delivery

Nanoparticles in Drug Delivery

• Nanoparticles are extremely small particles, derived from the Greek word "nano," meaning extremely small.
• Particle size ranges from 10-1000 nanometers in diameter.
• One nanometer is equal to one billionth of a meter (10^-9 meter).
• Nanoparticles are sub-nanosized colloidal delivery systems.
• They are composed of natural, synthetic, or semi-synthetic polymers that carry drugs.
• Drugs are either trapped within the polymer matrix or bound to the particle surface by physical adsorption or chemical reactions.
• Drugs can be added during nanoparticle preparation or to previously prepared nanoparticles.
• Nanoparticles range from 10 nm to 10 cm.
• Compared to other pharmaceutical particles like powders, granules, and tablets, nanoparticles are much smaller.
• Nanoparticles are used in drug delivery due to advantages such as reduced drug side effects, reduced fluctuation in circulating drug levels, more uniform effect of the drug, and more efficient drug distribution. This is further aided by how nanoparticles can be targeted to specific cells.
• Nanoparticle delivery can be used multiple ways for different types of drugs and administration.

Advantages

• Reduction in the frequency of drug dosages taken by the patient.
• Reduction of drug side effects.
• More uniform effect of the drug.
• Reduced fluctuation in circulating drug levels.
• Avoids hepatic first-pass metabolism.
• Nanoparticles are taken up by cells more efficiently than large particles.
• Targeted nano-drug carriers reduce drug toxicity and provide more efficient drug distribution.
• Protection from enzymatic and chemical degradation.
• Nanoparticles can be administered orally, nasally, parenterally, or intraocularly.

Disadvantages

• High cost.
• Reduced ability to adjust the dose.
• Requires highly sophisticated technology and skills to manufacture.
• Difficult to maintain stability of dosage form.
• Productively more difficult.

Ideal Characteristics

• Biochemical inert, nontoxic, and non-immunogenic.
• Stable physically and chemically in vivo and in vitro conditions.
• Controllable and predictable rate of drug release.
• Drug release should not affect the drug action.
• Restrict drug distribution to non-target cells, tissues, or organs.
• Specific therapeutic amount of drug release with uniform distribution.
• Carriers should be biodegradable and readily eliminated from the body without causing problems.
• The preparation should be easy, reasonable, and reproducible with low cost.

Polymers

• Polymers are macromolecules made up of repeating units of monomers.
• If monomers are identical, it's a homo-polymer; if they are different, it's a co-polymer.
• Natural polymers include biopolymers like DNA, proteins, and starch.
• Synthetic polymers include plastic and nylon.
• Polymers can be fabricated into various shapes and sizes.
• Polymers are the backbone of drug delivery systems from simple tablets to implants and can be used for food, drug delivery, and artificial organs.
• Polymers are used in the encapsulation or dispersion of drugs.
• Drug release can be controlled spatially (in a certain area) and temporally (over certain hours or years).
• Smart polymers react to biological stimuli to release drugs in a controlled manner.
• Multifunctional polymers can target specific organs or cells.
• The selection of properties can be controlled by monomer selection.
• Polymer biocompatibility is important.

Classification of Polymers

• Based on origin: Natural, semi-synthetic, or synthetic.
• Based on biodegradability: Most natural polymers are biodegradable. Synthetic polymers can be biodegradable or non-biodegradable.
• Based on architecture: Linear, cross-linked, or branched.
• Based on water solubility: Water soluble or water insoluble.

Biodegradable vs. Non-biodegradable

• Biodegradable polymers undergo enzymatic cleavage (over days or hours) and the resulting products are eliminated, or dissolve on their own.
• Non-biodegradable polymers remain intact, are excreted as is, or dissolved by diffusion. Ex. polysaccharides, cyclodextrins, polysiloxanes.

Smart Nanoparticles

• These are capable of releasing more drug molecules based on the stimulation of surrounding conditions like temperature, light, magnetic fields, chemical like pH conditions and small molecules, and biological items like enzymes, antibodies.
• Rexin G is an example to target metastatic cancer.

Natural vs Synthetic Polymers (examples)

• Natural: Proteins (Gelatin, Albumin, Lectins, Legumin), Polysaccharides (Alginate, Dextran, Chitosan, Agarose).
• Synthetic: Poly(ε-caprolactone), Polylactic acid, Poly(lactide-co-glycolide), Polystyrene.

This quiz explores the fascinating role of nanoparticles in drug delivery systems. Learn about their size, composition, and advantages in pharmaceutical applications. Test your knowledge on how these tiny particles improve drug effectiveness by minimizing side effects.