Pharmaceutics Midterm Flashcards
What can go wrong?
- Drug Recalls
- Impurity
- Labeling error - Drug Shortages
- Ex. Doxil
Drug Recalls: Impurity
- Mitoxantrone injection USP because “product may not support the specification results for known impurity prior to expiry”
- Piperacillin and Tazobactram for injection because “potential presence of particulate matter”
Drug Recalls: Labeling Error
- SteriMax-Vancomycin Hal Injection USP because “a typographical error was identified on one lot. Although unlikely, there is a potential for a dosing error to occur if the reconstitution information on the secondary cares of the French text is used” (not actually a recall, just a letter of notice)
- Atropine sulfate injection because “inaccurate dosing information on inner and outer labels”
Glaxo Whistle Blower Lawsuit
- 2002
- CHERYL ECKARD was assigned to lead a quality assurance team toe ablate a GSK plant in Cidra, Puerto Rico
- Found that “all systems were broken, the facility was broken, the equipment was broken, the processes were broken.” It was the worst thing she had ever seen.
- GSK pleaded guilty to a felony and admitted to distributing adulterated drugs (Paxil CR, Avandamet, Kytril and Bactroban)
- GSK paid $750 million in settlement
Drug Shortages
- Primary cause: Quality problems at the manufacturing facility
- Increasing in frequency and severity due to fewer companies making drugs
- 80% of drug shortages reported in 2010-2011 were sterile injectable products, with 28% of those being for oncology drugs
Drug Shortages: Common Manufacturing Issues
- Sterility of product
- Presence of foreign matter and impurities
- Crystallization of active ingredient
- Formation of precipitate
- Breakdown of equiment
Drug Shortages: Doxil
- Doxil is an anti-cancer medication
- 2011: FDA found major issues in the third party manufacturer’s facility and shut it down, leading to a shortage of Doxil for a year
- This drug is so important that there was even a push to approve a drug from Korea for the time being
- FDA ended up letting Jannsen rehab a small part of the facility in order to help deal with the shortage
Drug Shortages: Dynamics of Sterile Injectable Drug Shortages
Supply Distribution –> Drug Shortage
-Contributing Factors
+Manufacturing Issues: few producers, specialized facilities and dedicated lines
+Supply Chain Issues: Just-in-time inventory (prevents surplus and reduces expenses)
Drug Manufacturing and Pharmaceutical Analysis
- Arrival of starting and packaging material
- Sampling of starting materials
- Manufacturing
- Filling
- Labeling
- Packaging
- Documentation and control of finished product and product release
Pharmaceutical Analysis occurs at steps 1, 3 and 7
- Raw materials arrive and are stored in a separate area; samples are taken for analysis to ensure identity and purity of the material
- Following manufacture of the drug product, it is held in quarantine and samples are analyzed prior to filling in the designated containers
- Following release of finished product, samples are retained for evaluation
Roles of Pharmaceutical Analysis
- Assurance of raw material and drug product quality and stability
- Evaluation of the PK of a drug
- Therapeutic drug monitoring
- Clinical and forensic toxicology analysis
- Analysis of blood and urine samples for professional athletes
Pharmaceutical Analysis Terms: Identity Test
Identification of a drug or substance that does not involve quantitation
Pharmaceutical Analysis Terms: Assay
A quantitative analysis of a drug or substance
Pharmaceutical Analysis Terms: Analyte
The drug or substance being analyzed
Pharmaceutical Analysis Terms: Standard
A solution of a drug or substance of known concentration
Pharmaceutical Analysis Terms: Calibration Curve
A plot of the analytical signal versus concentration for a series of standards
UV-Vis Spectroscopy in Drug Analysis: UV-Vis Spectrum
UV: 200-380 nm
Visible: 380-750 nm
IR: >750 nm
Most drugs absorb in UV region, but some are colored and absorb in visible region
UV-Vis Spectroscopy in Drug Analysis: Absorbance of Radiation
- Atoms are held together by covalent bonds formed by electron sharing
- Electronic ground state: Energy of their electrons are at a minimum
- Radiation is absorbed through excitation of electrons involved in the bonds between atoms
- Electrons in weaker bonds can be excited by radiation in >200 nm range (lower wavelengths)
UV-Vis Spectroscopy in Drug Analysis: Chromophores and their Absorbance Maxima
- Carbonyl, ketone –> 271 nm
- Carbonyl, aldehyde –> 293 nm
- Carboxyl –> 204
- Amide –> 208
UV-Vis Spectroscopy in Drug Analysis: Qualitative Analysis
- Useful for identifying the drug based on wavelength max values
- Not an absolute identification technique because many drugs with similar structures have similar values
UV-Vis Spectroscopy in Drug Analysis: Quantitative Analysis
- Compares absorbance to a standard of the drug of known concentrations
- Can also calibrate curve obtained by analysis of several standards
UV-Vis Spectroscopy in Drug Analysis: Absorption Measurements
- Typically operate 200-800 nm
- Light passes through cuvette and amount of absorbed light is measured
- Cuvettes are Quartz or UV transparent
UV-Vis Spectroscopy in Drug Analysis: Beer-Lambert Law
Absorbance = a x b x c
a: molar absorptivity or extinction coefficient
b: path length
c: concentration
A = log (I0,I)
UV-Vis Spectroscopy in Drug Analysis: Drug Quantitation
-Using the Beer-Lambert Lab, a and b are constants, so we can solve for concentration
C(unknown) = A(unknown) x C(standard) / A(standard)
UV-Vis Spectroscopy in Drug Analysis: Example - Furosemide Standard Curve Method
Asked to determine if a lot of furosemide tablets contain the indicated amount of active pharmaceutical ingredient per tablet
- Assay a concentration in the middle of the calibration curve (about 0.025 mg/mL)
- Dilute 400 mg in 250 mL and then dilute 5 mL of that to 250 mL to get desired concentration (0.032 mg/mL)
- Measure absorption (A = 0.80)
- Using calibration curve equation (A = 26.67*C), C = 0.030 mg/mL
- Obtain % of expected concentration
0.030/0.032 = 93.8%
UV-Vis Spectroscopy in Drug Analysis: Example - Furosemide Single Point Determination
Asked to determine if a lot of furosemide tablets contain the indicated amount of active pharmaceutical ingredient per tablet
- Dilute 400 mg in 250 mL and then dilute 5 mL of that to 250 mL to obtain desired concentration (0.032 mg/mL)
- Measure absorption (A = 0.80)
- Using the Reference Table, the standard with a concentration of 0.030 mg/mL had an average absorbance of 0.81
C(u) = A(u) x C(s) / A(s)
C(u) = 0.030 mg/mL
4. Obtain % of expected concentration
0.030/0.032 = 93.8%
Fluorescence Spectroscopy in Drug Analysis
- Identification of a compound/drug
- Measurement of concentration of drug in a sample to determine amount of drug in dosage form, assess dissolution rate, or measure drug in biological sample
- Can use a bench top spectrofluorometer or HPLC with fluorescence detector
- Ex: Chlorpromazine, doxorubicin, quinine, tetracycline, ethinyl estradiol
Fluorescence Spectroscopy in Drug Analysis: Advantages
- Fluorescence is proportional to the intensity of light used to excite the molecules
- Background fluorescence is theoretically “zero”
- Approximately 10,000 times more sensitive than UV-vis
- Highly specific for molecule of interest since only certain molecules fluoresce
Chromatography in Drug Analysis
- Physical method of separating two or more components based on their distribution between two phases (stationary and mobile)
- Most commonly used analytical technique for drug analysis
Chromatography in Drug Analysis: Chromatographic Separations
- Column or Liquid Chromatography
- Adsorption
- Ion-exchange
- HPLC
- Size-exclusion
- Affinity - Thin Layer Chromatography
- Gas Chromatography
Chromatography in Drug Analysis: HPLC
High Performance Liquid Chromatography
-High resolution column chromatography that separates drugs based on their partitioning between a stationary phase and a mobile phase
Chromatography in Drug Analysis: HPLC - Columns
- Made of stainless steel to withstand high pressures
- Sometimes made of resilient polymeric material (PEEK - polyether ether ketone)
- Packed with different types of resins that allow for separation
- Dimensions: 0.5 cm x 25 cm
Chromatography in Drug Analysis: HPLC - Basis of Separation
- Drug molecule with high affinity for stationary phase will have longer residence time in the column and move more slowly
- Drug molecules with low affinity for stationary phase will have shorter residence time in the column and move more quickly
Chromatography in Drug Analysis: HPLC - Applications
Qualitative
-Identification of a drug substance by its chromatographic characteristics in a specific system
Quantitative
- Assay of the concentration of a drug based on the area under the peak relative to that for a standard of the drug
- Assay of a drug substance in the presence of other drugs or impurities
Chromatography in Drug Analysis: HPLC - Retention Time
- Time taken for an analyte to elute from the column and be detected by a monitor
- Depends on nature of compound, nature of column packing material, the nature of the solvent, and the flow rate
Chromatography in Drug Analysis: HPLC - Void Volume
Empty space not occupied by the stationary phase material
V(0) = t(0) x flow rate
Chromatography in Drug Analysis: HPLC - t(0)
Time taken for an unretained molecule to pass through the void volume
Chromatography in Drug Analysis: HPLC - Types
- Normal Phase - polar/hydrophilic
- Reverse Phase - nonpolar/hydrophobic
- Ion-Exchange - ionic charge
- Size-Exclusion - molecular size
- Chiral - optical isomers
Chromatography in Drug Analysis: HPLC - Normal Phase
-Forms hydrogen bonds with functional groups on drug molecules (e.g., OH, NH, etc.)
-Column matrix: Silica gel
+OH groups on silica gel H bond to polar groups on molecule (e.g., hydroxyl, amine, carboxylic acid)
-Order of elution: Less polar elutes first
-Common Solvents: Hexane > DCM > Isopropanol > Methanol
-Improve separation by increasing polarity of solvent in order to elute more polar compound more quickly
Chromatography in Drug Analysis: HPLC - Reverse Phase
- Forms hydrophobic interactions with non-polar functional groups on drug molecules
- Column matrix: silica derivatized with hydrocarbon chains C18, C8 or C2
- Order of elution: More polar elutes first
- Common Solvents: Water > Methanol > Acetonitrile > THF
- Improve separation by decreasing polarity of the solvent in order to elute less polar more quickly
Need for Health Canada and FDA
Agencies, policies and regulations have been established and developed largely in response to crises and adverse events