Prepared by: PARTHGuided by: Dr. Ashok MahajanAPMC College of Pharmaceuticaleducation and research,Himmatnagar
INDEXI. IntroductionII. Need for a Preformulation studyIII. Stages of Preformulation studiesIV. Analytical techniques and instruments for Preformulation studiesV. Regulatory requirements for PreformulationVI. Appendix: Physicochemical properties and analytical testing for drugVII. References
I .Introduction Definition: “Preformulation study is define as the process of optimizing the delivery of drug through determinations of physicochemical properties of the new compound that could affect drug performance and development of an efficacious, stable and safe dosage form.” Preformulation is the study of the chemical and physical properties of the drug components prior to the compounding process of the formulation. The purpose of the study is to understand the nature and characteristics of each component and to optimize conditions of the dosage form manufacture.
Essential information helpful in designing Preformulation evaluation of new drug:1. Compound identity % volatiles2. Structure Observations3. Formula and molecular weight 7. Analytical methods4.Therapeutic indication HPLC Assay Probable human dose TLC Assay Desired dosage form(s) UV/VIS Spectroscopy Bioavailability model(s) Synthetic route Competitive products Probable decay products5. Potential hazards 8. Key dates6. Initial bulk lots: Bulk scale up Lot number Toxicology start date Crystallization solvent(s) Clinical supplies preparation IND filing Particle size range Phase I testing Melting point
II.Need for a Preformulation Study Scientific and regulatory justifications for acquiring preformulation data include the following. 1. Establishment of drug specifications intended for toxicologic evaluation and clinical supply preparations 2. Formulation of clinical supplies and establishment of their preliminary Specifications 3. Providing scientific data to support dosage form development and evaluation of product efficacy, quality, stability, and bioavailability 4. Evaluation of the stability of early developed dosage forms 5. Fulfillment of the requirement of the CMC section of the IND and subsequent NDA or ANDA
III. Stages of Preformulation Studies The preformulation is performed in several stages with different development cycles, which are discussed in the following. Preformulation Report, Part 1: Physicochemical Properties and Analytical Testing for Drugs Preformulation Report, Part 2: Data Supporting the Development of Dosage Forms Preformulation Report, Part 3: Support for Quality Control and Finished Product Manufacturing
IV.Analytical techniques and instruments forpreformulation studies: A preformulation study is performed to gain insight from physicochemical and biological data into the design and development of dosage forms. Samples are taken in each study and analyzed qualitatively and/or quantitatively, according to the need. Analytical techniques are generally divided into two prevalent areas in the specific detection and separation sciences.
Analytical Preformulation Attribute TestIdentity Nuclear magnetic resonance (NMR) Infra red spectroscopy (IR) Ultraviolet spectroscopy (UV) Thin-layer chromatography (TLC) Differential scanning calorimetry (DSC) Optical rotation, where applicablePurity Moisture (water and solvents) Inorganic elements Heavy metals Organic impurities Differential scanning calorimetry (DSC) Melting pointAssay and Separation Titration Ultraviolet spectroscopy (UV) High-performance liquid chromatography (HPLC) Thin-layer chromatography (TLC)
A. Specific Detection Specific detection is based on specific responses related to the chemical characteristics of a molecule excited by a certain type of irradiation. In this detection method, measurement of the molecule of interest may usually be performed without separation from matrix materials or from other ingredients if appropriate instrumental adjustments are made. Techniques such as Fourier transform IR (FTIR), attenuated total reflectance (ATR), NIR, Raman spectroscopy are used with increased regularity. The detection of foreign metal contaminants is essential with inductively coupled plasma spectroscopy (ICP), atomic absorption (AA), and X-ray fluorescence.
1.UV spectroscopy UV absorptions are mainly electronic in nature and are associated with resonating structures in the molecule. The UV quantitative determination, generally performed in solution, is based on the Beer–Lambert law. In a Preformulation study, Certain UV techniques are worthy of discussion: Solubility, Dissolution rate, Molecular weight pKa Assay (potency) Mixtures: - resolving compound products Stability studies : hydrolysis, oxidation ,when degradation products have a different absorption maximum from the parent compound
ionization of benzoic acid affect its aqueous solubility, is also manifested in the ultraviolet absorption spectrum. Figure shows the UV spectra obtained for a 5 mg/mL solution of benzoic acid in methanol (i.e., the protonated form) and for the same concentration of substance dissolved in 0.1N sodium hydroxide solution (i.e., the ionized form). The spectrum of the protonated form is dominated by the peak at 228nm (molar absorptivity =11,900 L/mole), while the analogous peak of the ionized form is slightly blue-shifted to 225nm and is significantly less intense (molar absorptivity ¼8640 L/mole)
2.IR Spectroscopy Used for fingerprint identification of a drug molecule and the proof of its structure. IR absorption bands are characteristic of the functional group of a molecule as well as the structure configuration. The wavelength of the IR spectrum is 750–2500 μm. The sampling preparation techniques for IR determination are solution, drug dispersion in a KBr pellet, Nujol mulls, and direct determination by microscopic ATR preparation. An example of modern IR equipment is FTIR, which gives better quality determination.
3.Raman Spectroscopy When a particle is irradiated at a certain frequency, radiation scattered by the molecule contains photons of the same frequency as the incident radiation and may contain photons (weak signal) with a changed or shifted frequency. A nondestructive tool and requires little or no sample preparation. A sample may be analyzed in solid or powder form or in an aqueous solution and placed in glass containers such as an NMR tube, GC vial, test tube, light-path cell, or glass bottle. Aside from structure elucidation and functional group analysis, FT-Raman may be used for quantitative determination of polymorphs in a Preformulation study.
4.NIR Spectroscopy NIR is making significant progress through recent advances in pharmaceutical analysis. The advantage of this technique is the rapidity of analytical determinations without sample preparation and the use of solvent. The NIR spectrum is primarily related to the overtone variation. Hence, the absorption bands are generally weaker than those in the IR. The wavelength of the NIR spectrum is defined as 2500–3000 μm. The detection method is nondestructive. Therefore, it is suitable for use in on-line monitoring and meets 100% inspection requirements in quality control practice.
5.X-Ray Diffraction obtains information on substance structure at the atomic level. This technique allows measurement of both crystalline and noncrystalline materials. The analysis is nondestructive in nature and handles samples in the form of powders, solids, and liquids. The X-ray diffraction of a single crystal is employed for the determination of the absolute chemical structure. Quantitative ratios of two polymorphs and their percentage of crystallinity may also be determined.
the XRPD pattern of benzoic acid is shown in Figure One may define this particular crystal form by the angles of the five most intense scattering peaks, namely 8.15, 10.21, 16.24, 17.20, and 21.67 degrees 2q. Through use of the Bragg equation ,nzλ= 2d sin θ, calculated d-spacings for the five most intense scattering peaks, namely 10.840, 8.657, 5.453, 5.151, and 4.098 A ° , actually constitute a better definitionof this particular crystal form.
6. NMR Spectroscopy NMR involves the absorption of electromagnetic radiation in the radiofrequency of a longer wavelength spectrum. When a sample is placed with atomic nuclei of hydrogen (1H, protons), fluorine (15F), or phosphorous (31P) in a magnetic field, absorption of energy will occur. The nuclei shift from the preferred orientation with lowest energy to a less preferred, high-energy orientation at a particular frequency. Thus a plot of frequency versus intensity of radiation results in the NMR spectrum of a material. Spectra of NMR can be obtained in liquids or in solids. NM R spectra gives information about structure and atomic environment of molecule,
It consist of resonance bands associated with the carbon atoms in the aromatic nucleus and the carbon atom of the carboxylic acid group.
7. Mass Spectroscopy Mass spectra is the result of detection of charged particles or ions separated according to their mass to charge (m/e) ratio after ionization and acceleration through magnetic field. Mass spectra gives information about molecular weight of substance and what its degraded or metabolic products will be. MALDI like techniques are employed for high molecular weight substances like certain proteins.
8. Metal analysisa) Atomic absorption spectroscopyb) ICP Spectroscopyc) X-Ray fluorescence Pharmaceutical compounds such as ferrous sulfate, ferrous gluconate, zinc undecylenate, and magnesium stearate (a commonly used excipient) Sodium, potassium, zinc detection for certain preparations like protamine zinc insulin etc. presence of metal in pharmaceuticals, even in trace amounts, is a form of contaminant. For example, metallic ions may act as a catalyst in oxidation that may be detected in drug products.
B. Separation Sciences1. Thin-Layer Chromatography impurity profiling in drug development Involves most convenient, least inexpensive and portable equipment microscopic technique (it uses a very small sample) is simple and has a short development time general detection technique is to spray a sample with a detecting agent, which reacts chemically with the ingredient to be detected or visual observation under short- or long-wave UV light is also employed. The disadvantages of TLC include reproducibility, detection inconsistency, person-to-person variations, documentation, and electronic data reduction.
HPTLC: to overcome some drawbacks of TLC, especially in quantitative determination, A high-performance instrument has been developed with a fully automated sample applicator, a solvent-developing and -evaporating chamber, a precision-made dryer, a color developing agent sprayer, a light control chamber for visual or photographic observation, and a reflective spectrophometric detector Ingenious methods of quantitative determination are available that use a flame ionization detector (FID)
2. High-Pressure Liquid Chromatography HPLC is used extensively in the laboratory for quantization of drugs and related components. Identification of a drug component can simultaneously be determined by retention times in the chromatogram. reliable analytical tool for Preformulation study because of the high-resolution capacity, accuracy, and reproducibility of the equipment Its primary function includes search for and detection of impurities in drug substances, stability evaluation of dosage forms in terms of detection and quantization of degradation products. UV detector coupling with Micro-bore HPLC equipment is the most important analytical instrument for Preformulation
3. Capillary Electrophoresis: A separate technique employing narrow-bore tubes (10–200 μm i.d.) for high-efficiency resolution of both large and small molecules In free solution capillary electrophoresis (CE), the separation and migration of the molecules through the capillary are based on electrophoretic migration (based on net charge) and electrosomotic flow (the bulk flow of electrolyte buffer) Other mechanisms for separation depend on molecular size, isoelectric focusing, and hydrophobicity Modification of CE is micellar electrokinetic chromatography (MEKC), widely used for the separation of nonpolar compounds
4. Gas Chromatography: GC is used for speedy separation or for high-resolution separation of volatile or thermal labile substances. GC has good sensitivity, with detection limits of 1 ppb to 100 ppm. With the advances in HPLC, GC is utilized less often. It is still used for the analysis of retained solvents, such as the USP test for volatile organic solvents.5. Ion Chromatography: Ion chromatography is a modified version of HPLC with a capacity for precise and highly sensitive detection of inorganic ions in a complex matrix. IC has instrumental configurations similar to those of HPLC, but the stationary phase is an ion-exchange column, and the detector can be either an electrochemical detector or a colorimeter with a mixer to carry out color formation by chemical reaction with the detected ion
6. Supercritical Fluid Chromatography: SFC uses highly compressed gas above its critical temperature and pressure instead of an organic solvent as the solvent phase Gases such as carbon dioxide, nitrous oxide, and ammonia are commonly used The SFC detecting systems are those commonly used in GC, that is, FID. Major advantage is allowance in the analysis for thermal unstable compounds
C .Thermal Analytical methods1) Differential Scanning Calorimetry2) Hot Stage Microscopy3) Thermal Gravimetric Analysis4) Solution Calorimetry DSC is a precise method of measuring the endothermic and exothermic behaviors of sample materials. TGA measures the weight change (gains and losses) as a function of temperature or time is recorded which provides information about the material’s thermal stability and compositional analysis (e.g., moisture content of the materials).
The gas evolved during the heating process may be detected with FTIR or MS to provide additional information. TGA may be used to determine moisture content related to weight loss in isothermal or nonisothermal stability studies. Preformulation study, differentiation of polymorph from hydrate or identification of monohydrate from among other hydrates by DSC alone may not be possible.
The DSC thermogram of benzoic acid is shown and is seen to consist entirely of an endothermic transition associated with the melting phase transition of the compound. No thermal events were observed at the lower temperatures indicative of the existence of a solvatomorphic crystal form. Under the conditions of measurement, the melting endothermic transition is characterized by an onset temperature of 121.9C, a peak maximum of 123.7C, and an enthalpy of fusion equal to 138.9 J/g
V. Regulatory requirements for PreformulationA. Regulatory Compliance: FDA initiatives and other government regulations influence pharmaceutical manufacturing operations, including Preformulation studies and quality control systems.1) Current Good Manufacturing Practices: The cGMP is an FDA mandatory quality program designed to ensure that pharmaceutical products are consistently produced and controlled according to the quality standards appropriate to their intended use.2) Good Laboratory Practice: GLP covers research activities like raw data, documentation, standard operating procedures (SOP), protocols, final reports, and specimens (with some exceptions) must be retained.
3) International Conference on Harmonization: The ICH is intended to avoid duplication efforts for product registration and manufacturing in world trade from the United States, the European Union, and Japan to harmonize regulatory criteria and procedures. Ultimately, there will be one set of global requirements. Area of interest are Stability testing Quality specification (including impurities) Validation of manufacturing procedures and analytical methods CMC sections for product registration Toxicity testing Clinical testing of biotechnology-derived products
B. Quality Control for a Preformulation Study Personnel Qualification and Training Analytical Method Validation Written analytical procedure Instrument calibration Validation parameters: accuracy, precision, linearity, sensitivity System suitability criteria: the minimum acceptable performance criteria before each analysis Documentation and Standard Operating Procedures
APPENDIX 1: PHYSICOCHEMICAL PROPERTIES ANDANALYTICAL TESTING FOR DRUG SUBSTANCE Chemical StructureEmpirical Formula Molecular Weight Lot # of Drug Used: Reported By: Assay: Position: Reference: Notebook # Date of Report Issued:1. Chemical Properties 2. Identification of Drug SubstanceChemical structure UVMolecular weight IREmpirical formula NMRElemental analysis (C, H, N, O, Cl, etc.) Mass spectroscopy TLC Rf and HPLC retention time Melting point
3. Titration Methods 6. Synthetic ImpuritiesNonaqueous titration with curve Starting materials a: name andOther titration methods structure4. Chromatographic Techniques Pivotal impurities b: name andand Method Description structure TLC Degradant from synthesis c: name and HPLC structure GPC Other minor impurities d: name and Others structure5. Proposed Assay Methods for Description of Method of DetectionDrug Substance 7. HPLC Data Titration Impurities Retention Time UV 1. HPLC 2. GC 3. Others Typical chromatogram attached Description 8. Optical Rotation Typical spectrograph attached (Figure ) Comments
9. Solubility 11. Partition Coefficient Solubility in water and organic solvents: Value:mg/ml System: Aqueous Solubility as a Function of 12. Loss on DryingTemperature Drying temperature:Temperature ( C) Solubility :mg/ml Time period:Aqueous Solubility at Various Buffered pH Condition: _ in oven, _ in vacuoValues LOD in percent:pH Solubility (mg/ml)Buffer systemSolubility with SurfactantsSurfactant/Concentration Solubility (mg/ml)10. Dissociation Constant, pKapKa value:Method of determination:
VII . References1. Satinder Ahuja, Stephen Scypinski, Handbook of Modern Pharmaceutical Analysis, pp173-233.2. Leon Lachman, Herbet A.Lieberman, A theory and practice of Industrial Pharmacy, special Indian edition -2009,pp 171-1963. M.E.Aulton, Pharmaceutics The science of Dosage Form Design, Second edition, pp113-1384. Gilbert S. Banker, Christopher T. Rhodes, Modern Pharmaceutics, Fourth edition, Marcel dekker,Inc.5. Moji Christianah Adeyeye , Harry G. Brittain, Preformulation in solid dosage form development, Informa healhcare Inc.-2008,pp1-15,115-145.