Pharmaceutical Parenteral Practices Quiz

Parenterals

• Parenteral refers to injectable routes for drug administration, excluding oral routes.
• Sterility is essential in all parenteral preparations due to direct contact with internal body fluids
• Injectable preparations include small-volume injectable preparations, large-volume injectable preparations, irrigation fluids, and biologic preparations (vaccines, toxoids, antitoxins)
• Ophthalmic preparations are other examples of sterile dosage forms

Injections

• Injections are sterile, pyrogen-limited preparations administered parenterally.
• Pyrogens (bacterial endotoxins) are organic metabolic products from Gram-negative bacteria causing fever and hypotension when present in excessive amounts in intravenous injections.
• The term parenteral derives from Greek words "para" (outside) and "enteron" (intestine) and describes routes other than oral administration.
• Injections are primarily used in emergencies, noncompliance, or when other routes are ineffective (i.e., insulin).
• Injections are commonly administered in hospitals, extended care facilities, or clinics, and less frequently at home.

Parenteral Routes of Administration

• Drugs can be injected into various body organs and areas, including joints (intraarticular), joint fluid area (intrasynovial), spinal column (intraspinal), spinal fluid (intrathecal), arteries (intra-arterial), heart (intracardiac - emergencies), veins (intravenous - common route), muscle (intramuscular - IM), skin (intradermal), under the skin (subcutaneous - SC, sub-Q).

Intravenous Route

• Advantages: rapid onset of action, direct entry into the systemic circulation, bypassing absorption, and achieving precise and immediate optimum blood levels.
• Disadvantages: irreversible delivery, potential for thrombi and embolus, and increased risk of overdose and side effects compared to oral medications.
• Suitable veins: Basilic and cephalic veins (on the back of the hand and dorsal forearm).
• Antecubital vein is less preferred for IV therapy as it is a point of flexion and has a high risk of extravasation.

Parenteral Administration Techniques

• Strict aseptic precautions are mandatory to prevent infection.
• Injectable solutions, syringes, and needles must be sterile.
• The injection site must be disinfected to minimize the risk of introducing skin bacteria into the bloodstream.
• Before injection, aspirate (withdraw) the plunger of the syringe or squeeze the special bulb on IV sets to confirm proper needle placement.
• A backflow of blood into the administration set indicates proper needle placement.
• Large and small volume drug solutions are intravenously administered.
• Common use of a 1000mL solution containers for IV infusions within hospitals.

IV Infusion Hazards

• Thrombus formation (blood clot) may occur if the needle or catheter touches the vein wall, or if the solution is irritating to biologic tissues.
• The clot can circulate and cause embolus formation (obstruction of the blood vessel).
• This can be harmful to the patient, depending on location and severity.

IV Drugs and Emulsions

• Parenteral drugs are usually aqueous solutions to properly mix with blood and avoid precipitation.
• Precipitation can cause pulmonary microcapillary occlusion and blood flow blockage.
• Fat emulsions are used for extended parenteral nutrition, typically containing soy oil emulsified in egg yolk phospholipids in a glycerin-in-water vehicle.

Automated IV Delivery Systems

• Patient-controlled analgesia (PCA) systems are commercially available for intermittent self-administration of analgesics in surgical procedures, labor, or cancer treatment.

Intramuscular Injections

• Administered deep into skeletal muscles, aiming for areas distant from major nerves and blood vessels.
• Suitable injection sites: upper outer quadrant of the gluteus maximus (adults), deltoid muscle (adults), midlateral muscles of the thigh (infants and young children), and deltoid muscles of the upper arm (infants and young children).
• Injection volumes: 5mL in gluteal region, 2mL in deltoid.
• Potential for injury related to injection point, potential for paralysis from neural damage, abscess, embolism, cysts, hematoma, and sloughing of the skin/scarring.
• Should vary injection site during repeated injections.
• It is imperative to check for blood entry in the syringes.
• Certain medications (like iron dextran) may stain the tissue, so Z-track technique is used to minimize subcutaneous tissue staining; skin is displaced laterally prior to injection, the needle is then inserted, and the syringe is aspirated. Needle is then slowly withdrawn and skin released.

Subcutaneous Injections

• Medication in small volumes (0-1.3mL).
• Injection site: outer upper arm, anterior thigh, or lower abdomen.
• Rotating injection sites for frequent injections is crucial to avoid potential damage and/or complications.
• The site should be thoroughly cleaned before each injection.
• Syringe volumes up to 3mL and 24-26 gauge needles used.

Intradermal Injections

• Used for small volumes of medications suitable for diagnostic tests, desensitization, and immunization.
• Injection site: anterior forearm.
• Short and narrow needle (23-26 gauge) is inserted horizontally into the skin with a bevel facing up; the injection is made with the bevel just disappearing into the corium.

Specialized Access

• Central venous catheters are used for repeated injections over a period.
• They are used in situations like cancer chemotherapy, long-term antibiotic therapy, and total parenteral nutrition (TPN).

Official Types of Injections

• Injections are separated into five types (Injection, for injection, injectable emulsion, injectable suspension, For injectable suspension) based on physical states.

Solvents and Vehicles for Injections

• Water for injection (USP) is the most common solvent for injections.
• It is prepared by distillation or reverse osmosis, non-sterile, pyrogen free.
• Some formulations contain bacteriostatic agents whereas others do not need these.
• It is intended to be a solvent, vehicle, or diluent for already sterilized and packaged injectable medications.

Sterile Water for Injection

• Packaged in single-dose containers not larger than 1 L and should be pyrogen free.
• It can not contain antimicrobial agents.

Bacteriostatic Water for Injection

• Sterile water for injection containing one or more suitable antimicrobial agents.
• Usually packaged in vials containing a maximum of 30mL.

Sodium Chloride Injection

• Sterile, isotonic sodium chloride solutions in water injection.
• Usually contains no antimicrobial agents.
• Can be used as a sterile vehicle in solutions or suspensions of other drugs for parenteral administration; Sodium chloride injection is frequently used for maintaining catheter or IV line patency and usually 2mL is used for flushing the IV line after each use.

Ringer's Injection and Lactated Ringer's Injection

• Sterile solutions of sodium chloride, potassium chloride, and calcium chloride (Ringer's Injection, USP) in water for injection.
• Used as vehicles for other drugs or as electrolyte replenisher and plasma volume expander.
• Lactated Ringer's Injection contains sodium lactate, acting as both a fluid and electrolyte replenisher and a systemic alkalizer.

Nonaqueous Vehicles

• The use of non-aqueous solvents may be necessary given limited water solubility or hydrolysis susceptibility of the medication.
• Nonaqueous solvents must be non-irritating, non-toxic, non-sensitizing, not influence the medicinal agent's activity.

Methods of Sterilization

• Common methods for sterilizing pharmaceutical preparations include steam, dry heat, filtration, gas, and ionizing radiation.
• Steam sterilization (autoclaving) is often preferred for heat-stable products, but may be damaging to some products.
• Dry heat sterilization requires higher temperatures and longer exposure times.
• Filtration is suitable for heat-sensitive solutions.
• Gas sterilization (ethylene oxide) is useful for heat-sensitive and moisture-sensitive materials.
• Ionizing radiation sterilization is highly effective but requires specialized equipment.

Preparation of Parenteral Solutions

• The preparation of parenteral solutions involves dissolving ingredients according to Good Manufacturing Practices (GMPs), and then filtering the resulting solutions until clear. Solutions are then transferred quickly into proper containers for sterilization and final quality checks for sterility and pyrogens.

Packaging, Labeling, and Storage of Injections

• Injection containers should not interact physically or chemically with the medication.
• Glass containers for injections should be clear or light amber to permit inspection of contents.
• Single-dose containers (e.g., ampoules, vials) are used for single-use injections and are not resealable. Multiple-dose containers, with rubber closures, can be used repeatedly without loss of sterility.
• Specific labeling and storage requirements are determined by the individual monograph.

Small Volume Parenterals

• Small-volume injections, typically at or below 100mL.
• Common uses for this dosage form include medication for children and animals.

Insulin

• Among the most commonly used injectable medications
• Concerned with carbohydrate metabolism but also influences protein and fat metabolism.
• Facilitates glucose uptake in liver, muscle, and adipose tissue. Increases amino acid uptake and inhibits fat breakdown/ketone production.

Insulin Uses

• Administrated to patients with absent or abnormal pancreatic beta cell function to improve glucose, fat, protein metabolism.
• Used to treat diabetes that can not be controlled via diet or other oral anti-diabetic drug.
• Can be used to improve appetite and increase weight in non-diabetic malnutrition cases.

Insulin Administration

• Needle, pen devices, and infusion pumps are often used; nasal administration was initially available but later discontinued.

Insulin Strengths

• Originally available in strengths U-40 (40 U/mL) and U-80 (80 U/mL), with U-80 discontinued
• The preferred strength is now U-100 (100 U/mL). Some specific needs may still require alternative strengths or diluting fluid for handling, storage, or administration.

Insulin Types

• Basal insulins (intermediate-acting or long-acting) mimic continuous basal insulin secretion from the pancreas, helping suppress hepatic glucose production between meals and overnight.
• Bolus insulins (rapid or short-acting) mimic the postprandial rise in blood glucose levels.
• There is no ceiling dose in terms of insulin, but dosages are often in the range of 5-100 U per day.

Insulin Preparations

• Regular, Lispro (Humalog), Aspart (Novalog), Glulisine (Apidra), Isophane (NPH - or intermediate), Insulin Zinc Suspensions (or lente - or extended), Insulin Glargine (Lantus)

Insulin Considerations

• Labeling features the strength (U/mL) of the product. Should always be inspected for clarity and contamination. Proper labeling and storage are both imperative for safety and efficacy.