RCSI Medicines 1: Tools in Analysis of Drugs and Medicines PDF

RCSI Royal College of Surgeons in Ireland Coláiste Ríoga na Máinleá in Éirinn Tools in Analysis of Drugs and Medicines (I, II) Course: Masters in Pharmacy (MPharm), BSc Advanced Therapeutic Technologies Module: Medicines 1 Lecturer: Dr Sam Maher LEARNING OUTCOMES 1. Summarise the tool...

RCSI Royal College of Surgeons in Ireland Coláiste Ríoga na Máinleá in Éirinn Tools in Analysis of Drugs and Medicines (I, II) Course: Masters in Pharmacy (MPharm), BSc Advanced Therapeutic Technologies Module: Medicines 1 Lecturer: Dr Sam Maher LEARNING OUTCOMES 1. Summarise the tools used in the analysis of drugs and pharmaceutical dosage forms 2. Define accuracy and precision 3. Outline the role of spectroscopy in pharmaceutical science 4. Outline the role of chromatography in pharmaceutical science 5. MEDICINES QUALITY Quality control is integral to all modern industrial processes Types of analysis – Chemical – Physical – Microbiological The quality of a medicine may deviate from the standard required, but one must be certain that the quality of the analysis itself is of a suitable standard.  DOSAGE FORM STABILITY TESTING ATTRIBUTE TESTING BIOANALYSIS COMPATABILITY APPLICATIONS QUALITY TESTING TESTING OF ANALYSIS DRUG ISOLATION DRUG CHARACTERISATION DRUG IDENTIFICATION EXAMPLE OF SCIENTIFIC TOOLS IN R&D MICROSCOPY ELISA FLOW CYTOMETRY ELECTROPHYSIOLOGY BIOASSAY MOLECULAR DIAGNOSTICS BIOSPECIFIC INTERACTIONS PROTEOMICS BACTERIAL & MAMMALIAN CELL CULTURE PRE-CLINICAL ANIMAL MODELS  ANALYSIS DRUG TESTING IN BLOOD PREFORMULATION Preformulation is the stage in drug and dosage form development before formal formulation. QUALITY TESTING Quality assurance (QA) and quality control (QC) departments develop and follow standard internal operating procedures directed toward assuring the quality, safety, purity, and effectiveness of drug products. Specifications: A specification is defined as a list of tests, references to analytical procedures, and appropriate acceptance criteria, which are numerical limits, ranges, or other criteria for the tests described. Specifications are one part of a total control strategy for the drug substance and drug product designed to ensure product quality and consistency. Example tests in quality management – Stability – Impurities – Residual solvent DOSAGE FORM TESTING (EXAMPLES) TABLETS DISINTEGRATION TESTING (APPARATUS) FRIABILITY (APPARATUS) HARDNESS (APPARATUS) DISSOLUTION TESTING (APPARATUS) CREAM RHEOLOGY TESTING SUMMARY OF ANALYSIS IN PHARMACEUTICAL SCIENCE TYPES OF ANALYSIS QUALITATIVE ANALYSIS: Analysis of a substance in order to ascertain the nature of its chemical constituents QUANTITATIVE ANALYSIS: Analysis of a substance to determine the amounts and proportions of its chemical constituents VALIDATION OF ANALYTICAL PROCEDURES ACCURACY: Closeness of a measurement to the true value PRECISION: Closeness of two or more measurements to each other. The precision of an analytical procedures expresses the closeness of agreement (degree of scatter) between a series of measurements obtained from multiple sampling of the same homogenous sample under the prescribed conditions LEVELS OF PRECISION REPEATABILITY INTERMEDIATE PRECISION REPRODUCIBILITY  FACTORS THAT GIVE RISE TO INACCURACY AND IMPRECISION ANALYSIS OF PARACETAMOL TABLETS: A CASE OF RANDOM VERSUS SYSTEMATIC ERROR Paracetamol tablets (500mg) COMMON TERMINOLOGIES ANALYTICAL BLANK CALIBRATION LIMIT OF DETECTION LIMIT OF QUANTIFICATION LINEARITY RANGE ROBUSTNESS SELECTIVITY SENSITIVITY WEIGHT BY DIFFERENCE TITRIMETRIC AND CHEMICAL ANALYSIS METHODS PRINCIPLE: An analyte is chemically reacted with a standard soluton of reagent of precisely known concentration, the amount of which is used to estimate the purity of a sample. Applications Assay of drug, excipient and some formulations Specialist applications (e.g. Karl Fischer) Adv High precision, accuracy, robust, cheap, automatable, no calibration Limitations Non-selective, skilled operator Large amounts of sample and reagent SPECTROSCOPY Spectroscopy is the study of the interaction between EMR and molecules EMR travels through space at defined frequency (hz) and wavelengths (m) ULTRAVIOLET AND VISIBLE PRINCIPLE: Radiation in the wavelength of 200-700nm is passed through a solution of a compound. The electrons in the bonds become excited so that they occupy a higher quantum state and in the process absorb some of the energy passing through the solution. The more loosely held the electrons the longer the wavelength (lower the energy) Application Widely used method of quantification pKa, dissolution, solubility, release kinetics, reaction kinetics Strengths Easy to use, cheap, robust, precision Limitations Moderate selectivity Not applicable to all solutes INSTRUMENTATION Absorption ∞ Concentration CASE DRUG EXAMPLE: ASPIRIN MONITORING THE HYDROLYSIS OF ASPIRIN TO SALICYLIC ACID IR SPECTROMETRY DETAILED IN PCP1A: IR SPECTROSCOPY PRINCIPLE: EMR ranging between 400 cm-1 and 4000 cm-1 (2500 nm to 20000 nm) is passed through a sample and is absorbed by the bonds of the molecules in the sample causing them to stretch or bend. The wavelength of the radiation absorbed by the characteristics of the bond absorbing it Application Qualitative fingerprint check for excipients and drugs in manufacturing Preliminary compound identification Analysis in complex environments (creams, tablets etc) Detection of polymorphisms Strengths Complex fingerprint which is unique to the compound being examined Limitations Rarely used quantitatively due to sample preparation constraints Only useful for detection of gross impurities Technical knowledge required in sample preparation OTHER SPECTROSCOPIC ANALYSIS ATOMIC ABSORPTION SPECTROSCOPY FLORESCENCE SPECTROSCOPY RAMAN SPECTROSCOPY NUCLEAR MAGNETIC RESONANCE MASS SPECTROMETRY PRINCIPLE: Analyte is subjected to chemical ionisation or electron ionisation and resulting charged species are then accelerated into a vacuum chamber and separated on the basis of their mass to charge ratio (m/z ratio). The charged species produced in the spectrometer will generally include a range of different fragment ions, and under the right conditions, will also include the molecular ion, which is simply the intact test molecule minus 1 electron. Applications Drug identification and characterisation (molecular weight determination) Characterisation of impurities (in conjunction with GC and HPLC) Bioanalysis (in conjunction with GC and HPLC) Proteomics Limitations Expensive instruments, complexity that requires highly skilled operators, Less widely used in QC CHROMATOGRAPHY Chromatography is the most frequently use analytical technique in pharmaceutical analysis. Chromatography is the separation of the individual components of a mixture by exploitation of the difference in how analytes partition between a mobile phase and a stationary phase TYPES Column chromatography Thin layer chromatography Gas chromatography High pressure liquid chromatography RELATED TECHNIQUES: Capillary electrophoresis (not a type of chromatography) MODES Analytical: lower scale, analysis Preparative: higher scale, purification SEPARATION THEORY SEPARATION THEORY HIGH PERFORMANCE LIQUID CHROMATOGRAPHY PRINCIPLE: A liquid mobile phase is pumped under pressure through a stainless steel column containing particles of stationary phase. The analyte is loaded onto the top of the column and separation occurs via the relative lengths of time spent by its components in the stationary phase. Monitoring exit from the column is recorder by a variety of detectors (e.g. an integrated UV VIS spectrophotometer) Applications Excellent tool for the quantification of drugs and excipients Monitoring stability Measurement of drug or their metabolites in blood Strengths Strong performance in analytical metrics (accuracy, precision, robustness) Large variety of separation and detection modalities Automatable Limitations Sample preparation remains a key requirement Large quantities of organic solvent waste (disposal costs) CASE DRUG EXAMPLE: ASPIRIN RP-HPLC (UV detector) separation of aspirin from salicylic acid  Quality CHROMATOGRAPHY IN PURIFICATION Safety Efficacy Protein purification is a tandem series of processes used to isolate a protein of interest from a complex mixture OTHER TOOLS IN DRUG ANALYSIS GRAVIMETRIC ANALYSIS: Is a quantitative analytical technique that is based on the isolation of a substance by precipitation and weighing of the precipitate ELECTROANALYTICAL TECHNIQUES: Quantitative analysis by measurement of potential (Volts) and/or current (Amperes) in an electrochemical cells containing the analyte BIOANALYTICAL TECHNIQUES Bioanalytical science is the application of biological sciences to the study and analysis of biological samples and encompasses a multi billion pound global industry. FORENSICS PHARMACEUTICAL R&D DRUG MONITORING FOOD SCIENCE MEDICAL DIAGNOSTICS CLINICAL LABORATORY TESTING  IMMUNOASSAYS An immunoassay is a bioanalytical technique that uses the sensitivity and selectivity of the antibody-antigen reaction for the qualitative and quantitative analysis of analytes (drugs, endogenous biomolecules, metabolites) MOLECULAR DIAGNOSTICS E.G. TECHNOLOGY PLATFORMS FOR PHARMACOGENOMIC DIAGNOSTIC ASSAYS BIOANALYSIS Bioanalysis is the quantitative measurement of drugs, their metabolites, biological molecules, and biotics in biological systems BIOLOGICAL SPECIMENS BLOOD URINE SPUTUM FAECES SWEAT HAIR AND NAILS TISSUES EXHALED GASES  PRETREATMENT IN ANALYSIS Extraction is the removal of analyte from materials in the formulation matrix (tablets, creams) or from complex biological matrices (e.g. blood, sputum) which could (i) interfere in the analysis or (ii) potentially impede instrument function by non-adherence to operating specifications. The majority of samples must be pre-treated prior to analysis, and the methods used in extraction have significant bearing on the precision and accuracy of analysis. Common examples Solvent extraction Solid phase extraction CONTACT INFORMATION Sam Maher Lecturer in Pharmaceutics RCSI School of Pharmacy Royal College of Surgeons in Ireland 1st Floor Ardilaun House Block B 111 St Stephen’s Green, Dublin 2, Ireland T: 01-402-2362 E: [email protected]