Analytical methods development and validation play important roles in the discovery, development, and manufacture of pharmaceuticals. The official test methods that result from these processes are used by quality control laboratories to ensure the identity, purity, potency, and performance of drug products. This review gives information regarding various stages involved in development and validation of analytical methods like LC, HPLC, MS.
High performance liquid chromatography (HPLC); Liquid- liquid extraction (LLE); UV detector; Mass Spectrometry; NMR; limit of detection (LOD); Limit of quantitation (LOQ)
Analytical method development
Analytical chemistry deals with methods for identification, separation, and quantification of the chemical components of natural and artificial materials . The choice of analytical methodology is based on many considerations, such as: chemical properties of the analyte and its concentration , sample matrix, the speed and cost of the analysis, type of measurements i.e., quantitative or qualitative and the number of samples. A qualitative method yields information of the chemical identity of the species in the sample. A quantitative method provides numerical information regarding the relative amounts of one or more of the analytes in the sample.
The steps of method development and method validation depend upon the type of method being developed. However, the following steps are common to most types of projects:
• Method development plan definition
• Background information gathering
• Laboratory method development, it includes various stages namely sample preparation, specific analytical method, detection and data processing
• Generation of test procedure
A well-developed method should be easy to validate. A method should be developed with the goal to rapidly test preclinical samples, formulation prototypes, and commercial samples. There are five common types of analytical methods, each with its own set of validation requirements:
• Identification tests
• Potency assays
• Quantitative tests for impurities
• Limit test for the control of impurities
• Specific tests
The first four tests are universal tests, but the specific tests such as particle-size analysis and X ray diffraction are used to control specific properties of the active pharmaceutical ingredient (API) or the drug product [3,4].
The most widely used methods for quantitative determination of drugs and metabolites in biological matrices such as blood, serum, plasma, or urine includes Gas chromatography (GC), High-performance liquid chromatography (HPLC) [5,6], Thin layer chromatography (TLC), combined GC and LC mass spectrometric (MS) procedures such as LC-MS [7,8], LC-MS-MS [9,10], GC-MS [11,12], and GC-MSMS, techniques like NMR is used for structure identification.
Chromatography in different forms is the leading analytical method for separation of components in a mixture. The chromatographic procedure for the separation of substances is based on differences in rates of migration through the column arising from different partition of the compounds between a stationary phase (column packing) and a mobile phase transported through the system . Chromatographic methods can be classified according to the physical state of the mobile phase into the following basic categories: gas chromatography (GC), supercritical fluid chromatography (SFC) and liquid chromatography (LC). The technique was originally developed by the Russian botanist M.S. Tswett in 1903 [14,15].
Today TLC is rapidly becoming a routine analytical technique due to its advantages of low operating costs, high sample throughput and the need for minimum sample preparation. The major advantage of TLC is that several samples can be run simultaneously using a small quantity of mobile phase unlike HPLC thus reducing the analysis time and cost per analysis [16,17]. An enhanced form of thin layer chromatography (TLC) is called as High performance thin layer chromatography (HPTLC) [18,19]. A number of enhancements can be made to the basic method of thin layer chromatography to automate the different steps, to increase the resolution achieved and to allow more accurate quantitative measurements.
Liquid chromatography can be categorized on the basis of the mechanism of interaction of the solute with the stationary phase as: adsorption chromatography (liquid-solid chromatography), partition chromatography (liquid-liquid chromatography), ion-exchange chromatography (IEC), size exclusion chromatography (SEC) and affinity chromatography.
Early work in liquid chromatography was based on highly polar stationary phases, and nonpolar solvents served as mobile phases, this type of chromatography is now referred to normal-phase liquid chromatography (NPLC) . Chromatography on bare silica is an example of normal-phase chromatography. In reversed-phase high performance liquid chromatography(RP-HPLC), the stationary phase is nonpolar [21,22], often a hydrocarbon, and the mobile phase is relatively polar . In RP-HPLC, the most polar component is eluted first, because it is relatively most soluble in the mobile phase.
The definite break-through for liquid chromatography of low molecular weight compounds was the introduction of chemically modified small diameter particles (3 to 10μm) e.g., octadecyl groups bound to silica in the late 1960s. The new technique became rapidly a powerful separation technique and is today called high performance liquid chromatography (HPLC).
HPLC-UV diode-array detection (DAD) [24,25] and HPLC-MS techniques take advantage of chromatography as a separation method and DAD or MS as identification and quantification methods. The HPLC equipment consists of a high-pressure solvent delivery system, a sample auto injector, a separation column, a detector (UV or DAD) a computer to control the system and display results.
Ultra performance liquid chromatography (UPLC) is a recent technique in liquid chromatography, which enables significant reductions in separation time, solvent consumption and analysis time as compared to the conventional HPLC [26,27].
The purpose of sample preparation is to create a processed sample that leads to better analytical results compared with the initial sample. The prepared sample should be an aliquot relatively free of interferences that is compatible with the HPLC method and that will not damage the column . The main sample preparation techniques are liquid-liquid extraction (LLE) [29,30] and solid-phase extraction (SPE) . In these methods the analyte of interest was separated from sample matrix, so that as few potentially interfering species as possible are carried through to the analytical separation stage.
After the chromatographic separation, the analyte of interest is detected by using suitable detectors. Some commercial detectors used in LC are: ultraviolet (UV) detectors , fluorescence detectors, electrochemical detectors, refractive index (RI) detectors and mass spectrometry (MS) detectors. The choice of detector depends on the sample and the purpose of the analysis.
The UV detectors are the most common HPLC detectors since they are robust, cheap, easy to handle, and since many solutes absorb light in this frequency range [33,34]. The ordinary UV detector measures the absorbance at one single wavelength at the time. A diode-array detector (DAD) can measure several wavelengths at the same time, and since no parts are moved to change wavelength or to scan, there are no mechanical errors or drift with time.
DAD detectors have been proposed for various applications, such as preliminary identification of a steroidal glycoside in seed , peptide mapping , assay of sulfamethazine in animal tissues , or identification of pesticides in human biological fluids .
Mass Spectrometry: Mass spectrometry (MS) is a widely used detection technique that provides quantitative and qualitative information about the components in a mixture . In qualitative analysis it is very important to determine the molecular weight of unknown compound and MS is capable of that. MS is also more sensitive than an UV detector for quantification. An MS detector consists of three main parts: the ionization source where the ions are generated, the mass analyzer, which separates the ions according to their massto- charge ration (m/z), and the electron multiplier (detector). There are several types of ion sources, which utilize different ionization techniques for creating charged species. Three popular ionization techniques are: electrospray ionization (ESI) , atmospheric pressure chemical ionization (APCI) and matrix-assisted laser desorption (MALDI). Electrospray is the most widely used ionization technique when performing LC-MS [44–47].
NMR: Nuclear magnetic resonance (NMR) spectroscopy is a very powerful tool to determine the structure of compounds [48,49]. This nondestructive spectroscopic analysis can reveal the number of atoms and their connectivity’s, and thus the conformations of the molecules.
Near infrared (NIR) spectroscopy is a quick, non-destructive method that is amenable for spot analysis application. In the last two decades, it has been increasingly used in pharmaceutical analysis .
“Validation of an analytical method is the process by which it is established by laboratory studies, that the performance characteristics of the method meet the requirements for the intended analytical application – “.
The methods were validated according to International Conference on Harmonization (ICH) guidelines for validation of analytical procedures [52,53]. Validation is required for any new or amended method to ensure that it is capable of giving reproducible and reliable results, when used by different operators employing the same equipment in the same or different laboratories . The type of validation program required depends entirely on the particular method and its proposed applications.
Typical analytical parameters used in assay validation include:
• Detection Limit
• Quantitation Limit 
Accuracy: Accuracy is a measure of closeness between the measured and real value .
Precision: Precision of an analytical procedure expresses the closeness of agreement between a series of measurements obtained from multiple sampling of the same homogeneous sample under the prescribed conditions of repeatability , intermediate precision reproducibility.
Specificity: Specificity is the ability to measure the desired analyte in the presence of components which may be expected to be present. Typically these might include impurities, degradants, matrix, etc .
Detection limit: The detection limit of an individual analytical procedure is the lowest amount of analyte in a sample which can be detected but not necessarily quantitated as an exact value.
Can be determined
– Signal to Noise ratio 
– Standard Deviation of the Response and the Slope 
Quantitation limit: The quantitation limit of an individual analytical procedure is the lowest amount of analyte in a sample which can be quantitatively determined with suitable precision and accuracy. The quantitation limit is a parameter of quantitative assays for low levels of compounds in sample matrices, and is used particularly for the determination of impurities and/or degradation products.
Linearity: The linearity of an analytical procedure is its ability to obtain test results which are directly proportional to the concentration of analyte in the sample. Test results should be evaluated by appropriate statistical methods, for example, by calculation of a regression line by the method of least squares.
Range: The range of an analytical procedure is the interval between the upper and lower concentration of analyte in the sample for which it has been demonstrated that the analytical procedure has a suitable level of precision, accuracy and linearity.
Robustness: The robustness of an analytical procedure is a measure of its capacity to remain unaffected by small, but deliberate variations in method parameters  and provides an indication of its reliability during normal usage.
Only specificity is needed for an identification test. However, the full range of specificity, accuracy, linearity, range, limit of detection (LOD) , limit of quantitation (LOQ) , precision, and robustness testing is needed for more-complex methods such as quantitative impurity methods.
Recent development in pharmaceutical and biotechnological field generates a cumulative demand for analytical methods. Rapid and accurate quantification of the substrate and drug product is important in the process development. Improvements in analytical instrumentation leads to development of new techniques like isocratic and gradient RP-HPLC, which evolved as the primary techniques for the analysis of nonvolatile APIs and impurities. These analytical methods are critical elements of pharmaceutical development so it is very important to develop efficient and accurately validated analytical methods to develop safe and effective drugs.
- Skoog DA, West DM, Holler FJ (1996) Fundamentals of analytical chemistry. (8thEdn), Fort Worth: Saunders College Pub.
- Song HH, Choi KS, Kim CW, Kwon YE (2009) Pharmacokinetic Profiles of Two Branded Formulations of Piroxicam 20mg in Healthy Korean Volunteers by a Rapid Isocratic HPLC Method. J Bioequiv Availab 1: 074-079.
- Nanjwade BK, Ali MS, Nanjwade VK, Manvi FV (2010) Effect of Compression Pressure on Dissolution and Solid State Characterization of Cefuroxime Axetil. J Anal Bioanal Tech 1:112.
- Yue PF, Yuan HL, Yang M, Zhu WF (2009) Preparation, Char-acterization and Pharmacokinetics in Vivo of Oxymatrine-Phospholipid Complex. J Bioequiv Availab 1: 099-102.
- Maithani M, Singh R (2011) Development and Validation of a Stability-Indicating HPLC Method for the Simultaneous Determination of Salbutamol Sulphate and Theophylline in Pharmaceutical Dosage Forms. J Anal Bioanal Tech 1:116.
- Chitlange SS, Chaturvedi KK, Wankhede SB (2011) Development and Validation of Spectrophotometric and HPLC Method for the Simultaneous Estimation of Salbutamol Sulphate and Prednisolone in Tablet Dosage Form. J Anal Bioanal Tech 2:117.
- Saber AL, Amin AS (2011) Utility of Ion-Pair and Charge Transfer Complexation for Spectrophotometric Determination of Domperidone and Doxycycline in Bulk and Pharmaceutical Formulations. J Anal Bioanal Tech 1:113.
- Bai L, Ma Z, Yang G, Yang J, Cheng J (2011) A Simple HPLC Method for the Separation of Colistimethate Sodium and Colistin Sulphate.J Chromatograph Separat Techniq 1:105.
- Babu ARS, Thippeswamy B, Vinod AB (2011) Determination of Tacrolimus in Rat Whole Blood Utilizing Triple Quadrupole LC/MS. J Anal Bioanal Tech 2:118.
- Junior EA, Duarte LF, Pereira R, Pozzebon JM, Tosetti D, et al. (2011) Gabapentin Bioequivalence Study: Quantification by Liquid Chromatography Coupled to Mass Spectrometry. J Bioequiv Availab 3: 187-190.
- Hsieh CL, Wang HE, Ker YB, Peng CC, Chen KC, et al. (2011) GC/MS Determination of N-butyl-N-(3-carboxypropyl) Nitrosamine (BCPN) in Bladder Cancers – The Skewed Molecular Interaction Caused Retention Time Shift. J Anal Bioanal Tech 1:115.
- Ekeberg D, Norli HR, Stene C, Devle H, Bergaust L (2010) Identification of Brominated Flame Retardants in Sediment and Soil by Cyclohexane Extraction and Gas Chromatography Mass Spectrometry. J Chromatograph Separat Techniq 1:102.
- Ravali R, Phaneendra M, Bhanu Jyothi K, Ramya Santhoshi L, Sushma K (2011) Recent Trends in Analytical Techniques for the Development of Pharmaceutical Drugs. J Bioanal Biomed R1: 002.
- M.S. Tswett, Tr Protok, Otd. Biol., 14 (1903, publ. 1905) 20.
- Verzele M, Dewaele C (1985) Preparative High Performance Liquid Chromatography, A Practical Guidline. TEC Dent, Belgium.
- Dhaneshwar SR, Salunkhe JV, Bhusari VK (2010) Validated HPTLC Method for Simultaneous Estimation of Metformin Hydrochloride, Atorvastatin and Glimepiride in Bulk Drug and Formulation. J Anal Bioanal Tech 1:109.
- Abdelkawy M, Metwaly F, El Raghy N, Hegazy M, Fayek N (2011) Simultaneous determination of Ambroxol Hydrochloride and Guaifenesin by HPLC, TLCSpectro densitometric and multivariate calibration methods in pure form and in Cough Cold Formulations. J Chromatograph Separat Techniq 2:112.
- Bari SB, Bakhshi AR, Jain PS, Surana SJ (2011) Development and Validation of Stability-Indicating Tlc Densitometric Determination of Ropinirole Hydrochloride in Bulk and Pharmaceutical Dosage Form. Pharm Anal Acta 2:125.
- Jain PS, Khatal RN, Jivani HN, Surana SJ (2011) Development and Validation of TLC-densitometry Method for Simultaneous Estimation of Brimonidine tartrate and Timolol maleate in Bulk and Pharmaceutical Dosage Form. J Chromatograph Separat Techniq 2:113.
- Skoog DA, Leary JJ (1992) Principles of Instrumental Analysis. Harcourt Brace College Publishers.
- Subbaiah PR, Kumudhavalli MV, Saravanan C, Kumar M, Chandira RM (2010) Method Development and Validation for estimation of Moxifloxacin HCl in tablet dosage form by RP-HPLC method. Pharm Anal Acta 1:109.
- Sultana N, Arayne MS, Naveed S (2011) RP-HPLC Method for Simultaneous Determination of Captopril and Diuretics: Application in Pharmaceutical Dosage Forms and Human Serum. J Chromatograph Separat Techniq 2:109.
- Krstulovic AM, Brown PR (1982) Reversed-Phase High Performance Liquid Chromatography, Wiley, New York.
- Sawant L, Prabhakar B, Pandita N (2010) Quantitative HPLC Analysis of Ascorbic Acid and Gallic Acid in Phyllanthus Emblica. J Anal Bioanal Tech 1:111.
- El-Sayed AAY, Mohamed KM, Hilal MA, Mohamed SA, Aboul-Hagag KE, et al. (2011) Development and Validation of High-Performance Liquid Chromatography-Diode Array Detector Method for the Determination of Tramadol in Human Saliva. J Chromatograph Separat Techniq 2:114.
- Reddy YR, Kumar KK, Reddy MRP, Mukkanti K (2011) Rapid Simultaneous Determination of Sumatriptan Succinate and Naproxen Sodium in Combined Tablets by Validated Ultra Performance Liquid Chromatographic Method. J Anal Bioanal Tech 2:121.
- Naveen Kumar Reddy G, Rajendra Prasad VVS, Maiti NJ, Nayak D, Prashant Kumar M (2011) Development and Validation of a Stability Indicating UPLC Method for Determination of Moxifloxacin Hydrochloride in Pharmaceutical Formulations. Pharm Anal Acta 2:142.
- Nanjwade BK, Patel DJ, Parikh KA, Nanjwade VK, Manvi FV (2011) Development and Characterization of Solid-Lipid Microparticles of Highly Insoluble Drug Sirolimus. J Bioequiv Availab 3: 011-015.
- Yi SJ, Shin HS, Yoon SH, Yu KS, Jang IJ, et al. (2011) Quantification of Ticlopidine in Human Plasma Using Protein Precipitation and Liquid Chromatography Coupled with Tandem Mass Spectrometry. J Bioanal Biomed 3: 059-063.
- Rajender G, Narayana NGB (2010) Liquid Chromatography-Tandem Mass Spectrometry Method for Determination of Paclitaxel in Human Plasma. Pharm Anal Acta 1:101.
- Yang G, Liu Y, Liu H, Yang C, Bai L, et al. (2010) Preparation of a Novel Emulsion-Templated MIP Monolith and its Application for on Line Assay of Nifedipine in Human Plasma. J Chromatograph Separat Techniq 1:103.
- Moreno RA, Sverdloff CE, Oliveira RA, Oliveira SE, Borges DC, et al. (2009) Comparative bioavailability and pharmacodynamic aspects of cyclobenzaprine and caffeine in healthy subjects and the effect on drowsiness intensity. J Bioequiv Availab 1: 086-092.
- Puri A, Mehdi B, Panda NB, Dhawan GDPS (2011) Estimation of Pharmacokinetics of Propofol in Indian Pateints by HPLC Method. J Anal Bioanal Tech 2:120.
- Remsberg CM, Yáñez JA, Vega-Villa KR, Davies NM, Andrews PK, et al. (2010) HPLC-UV Analysis of Phloretin in Biological Fluids and Application to Pre- Clinical Pharmacokinetic Studies. J Chromatograph Separat Techniq 1:101.
- Sarker SD, Lafont R, Girault JP, Sik V, Dinan L (1998) Pharmaceutical Biology. 36: 202-206.
- Sievert P, Hancock WS (1996) New methods in peptide mapping for the characterization of proteins, CRC press, Inc., New York.
- Furusawa N (2001) Determining the procedure for routine residue monitoring of sulfamethazine in edible animal tissues. Biomed Chromatogr 15: 235-239.
- Guiochon G, Katti A (1987) Preparative Liquid Chromatography. Chromatographia 24: 165.
- Bao Y, Li C, Shen H, Nan F (2004) Determination of saikosaponin derivatives in Radix bupleuri and in pharmaceuticals of the chinese multiherb remedy xiaochaihu-tang using liquid chromatographic tandem mass spectrometry. Anal Chem 76: 4208-4216.
- Liu L, Cheng Y, Zhang H (2004) Phytochemical analysis of anti-atherogenic constituents of Xue-Fu-Zhu-Yu-Tang using HPLC-DAD-ESI-MS. Chem Pharm Bull 52: 1295-1301.
- Liu SJ, Liu ZX, Ju WZ, Zhou L, Chen M, et al. (2010) Development and Validation of a Liquid Chromatographic/ Mass Spectrometric Method for the Determination of Saikosaponin a in Rat Plasma and its Application to Pharmacokinetic Study. J Anal Bioanal Tech 1:104.
- Mahatthanatrakul W, Pradabsang C, Sriwiriyajan S, Ridtitid W, Wongnawa M (2011) Bioequivalence of a Generic Quetiapine (Ketipinor) in Healthy Male Volunteers. J Bioequiv Availab 3: 108-113.
- Yasuhara A, Tanaka Y, Makishima M, Suzuki S, Shibamoto T (2011) LC-MS Analysis of Low Molecular Weight Carbonyl Compounds as 2,4-Dinitrophenylhydrazones Using Negative Ion Mode Electronspray Ionization Mass Spectrometry. J Chromatograph Separat Techniq 2:108.
- Ghosh C, Shinde CP, Chakraborty BS (2010) Ionization Polarity as a Cause of Matrix Effects, its Removal and Estimation in ESI-LC-MS/MS Bio-analysis. J Anal Bioanal Tech 1:106.
- Ghosh C, Gaur S, Singh A, Shinde CP, Chakraborty BS (2011) Estimation of Nevirapine from Human Plasma by LC-ESI-MS/MS: a Pharmacokinetic Application. J Bioequiv Availab 3: 020-025.
- Ding MJ, Yuan LH, Li Y, Wang S, Wu XL, et al. (2011) Pharmacokinetics and Bioequivalence Study of Simvastatin Orally Disintegrating Tablets in Chinese Healthy Volunteers by LC-ESI-MS/MS. J Bioequiv Availab 3: 032-037.
- Ghosh C, Gaur S, Shinde CP, Chakraborty B (2011) A Systematic Approach to Overcome the Matrix Effect during LC-ESI-MS/MS Analysis by different Sample Extraction Techniques. J Bioequiv Availab 3: 122-127.
- Afergan E, Najajreh Y, Gutman D, Epstein H, Elmalak O, et al. (2010) Drug Physical State and Fraction in Alendronate Liposomes. J Bioanal Biomed 2: 125-131.
- Griffi ni P, James AD, Roberts AD, Pellegatti M (2010) Metabolites in Safety Testing: Issues and Approaches to the Safety Evaluation of Human Metabolites in a Drug that is Extensively Metabolized. J Drug Metabol Toxicol 1:102.
- Ni Z, Feng YC, Hu CQ (2011) Analyzing the Methods to Remove Artifacts Encountered in the Development of a NIR Quantitative Model for Powder Medicines. J Anal Bioanal Tech 1:114.
- Validation of compedial Assays-Guidelines Pharmacopeial Convention, Rockvilie, MD, 1985.
- Chandrashekhar N, Patel HR, Karvekar MD, Suresh BAR (2011) Simultaneous Estimation of Aceclofenac, Paracetamol and Tizanidine in Their Combined Dosage Forms by Spectrophotometric and RP- HPLC Method. J Anal Bioanal Tech 2:123.
- Sonawane LV, Bari SB (2010) Development and Validation of RP-HPLC Method for The Simultaneous Estimation of Amoxicillin Trihydrate and Bromhexine Hydrochloride from Oily Suspension. Pharm Anal Acta 1:107.
- Balderas-Acata JI, Ríos-Rogríguez Bueno EP, del Castillo-García S, Espinosa- Martínez C, Burke-Fraga V, et al. (2011) Bioavailability of Two Coated-Tablet Formulations of a Single Dose of Pantoprazole 40 mg: An Open-Label, Randomized, Two-Period Crossover, Comparison in Healthy Mexican Adult Volunteers. J Bioequiv Availab 3: 077-081.
- Susantakumar P, Gaur A, Sharma P (2011) Comparative Pharmacokinetics, Safety and Tolerability Evaluation of Acyclovir IR 800 Mg Tablet in Healthy Indian Adult Volunteers Under Fasting and Non-fasting Conditions. J Bioequiv Availab 3: 128-138.
- Haider M (2011) Development and Validation of a Stability Indicating HPLC Method for the Estimation of Butamirate Citrate and Benzoic Acid in Pharmaceutical Products. J Chromatograph Separat Techniq 2:111.
- Bari SB, Jain PS, Bakshi AR, Surana SJ (2011) HPTLC Method Validation for simultaneous determination of Tamsulosin Hydrochloride and Finasteride in Bulk and Pharmaceutical Dosage Form. J Anal Bioanal Tech 2:119.
- Liu Y, Hou S, Wang L, Yang S (2010) Development and Validation of a Liquid Chromatography Method for the Analysis of Paromomycin Sulfate and its Impurities. J Anal Bioanal Tech 1:102.
- Jain PS, Tatiya AU, Bagul SA, Surana SJ (2011) Development and Validation of a Method for Densitometric Analysis of 6-Gingerol in Herbal extracts and Polyherbal Formulation. J Anal Bioanal Tech 2:124.
- Sakurada T, Zusi S, Kobayashi E, Satoh N, Ueda S (2010) Simultaneous Determination of Morphine, Morphine Glucuronides (M3G, M6G) and Oxycodone in Human Plasma by High-performance Liquid Chromatography. J Anal Bioanal Tech 1:101.
- Fayyad MK, Misha AK, Yousef Al-Musaimi OI (2010) Effect of Temperature, Wavelength, pH, Ion Pair Reagents and Organic Modifi ers’ Concentration on the Elution of Cystatin C. Stability of Mobile Phase. J Anal Bioanal Tech 1:103.
- Salvi VS, Sathe PA, Rege PV (2010) Determination of Tinidazole and Ciprofloxacin Hydrochloride in Single Formulation Tablet using Differential Pulse Polarography. J Anal Bioanal Tech 1:110.
- Rao BU, Nikalje AP (2010) Determination of Glipizide, Glibenlamide and Glimeperide in a Tablet Dosage Form in the Presence of Metformin Hydrochloride by Ion Pair -Reversed Phase Liquid Chromatographic Technique. J Anal Bioanal Tech 1:105.
- *Corresponding Author:
- Nishant Toomula
Department of Biotechnology
GITAM Institute of Technology, GITAM University
E-mail : email@example.com
Received date: October 15, 2011; Accepted date: December 02, 2011; Published date: December 06, 2011
Citation: Nishant T, Arun Kumar, Sathish Kumar D, Vijaya Shanti B (2011) Development and Validation of Analytical Methods for Pharmaceuticals. J Anal Bioanal Tech 2:127. doi: 10.4172/2155-9872.1000127
Copyright: © 2011 Nishant T, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Continue at: https://www.omicsonline.org/development-and-validation-of-analytical-methods-for-pharmaceuticals-2155-9872.1000127.php?aid=3153
The text above is owned by the site above referred.
Here is only a small part of the article, for more please follow the link