Review Article On Analytical Method Development And Method Validation On UV And HPLC Of Drug Losartan

The idea of quality assurance was restricted to product inspection, which took place at the very end of the production process and resulted in the product's acceptance or rejection. The term "losartan potassium" refers to the (basic) potassium salt of the aromatized negatively charged tetrazole that is typically used in marketing. The molecule functions as a bio isostere by substituting an extended biphenyl group with a tetrazole for the carboxylic acid. The first medication from ABB to go on sale is losartan. It is connected to cardiovascular problems and utilized in the treatment of Hypertension.by specifically blocking the angiotensin receptor, losartan prevents vasoconstriction and the secretion of aldosterone, which lowers blood pressure and enhances cardiovascular health. In addition to controlling hypertension, it also has positive side effects on platelet aggregation, uric acid metabolism, diabetes, and atrial fibrillation, all of which help to prevent stroke in the patient.  The measurement of Losartan potassium in pharmaceutical goods has been done using a variety of analytical techniques, including spectrophotometry, capillary electrophoresis, high performance thin layer chromatography, and capillary electrochromatography (CEC). Numerous analytical techniques for Losartan tablet quantification using HPLC are reported in the literature. All of the previously described approaches were laborious to analyse or used mobile phases that required buffer solution pH adjustments, which made them unsuitable for routine testing of quality control samples for dissolution studies.[1] Angiotensin converting enzyme (ACE) inhibitors were less clinically effective than angiotensin receptor blockers (ARBs) at reducing adverse events, according to current research. Losartan (LOS) and valsartan (VLS) are two of the ARBs that are most commonly used globally. Small resistance artery vasodilation is the goal of LOS and VLS, and thus attenuates the total peripheral resistance [2].

       
           
       
    (Fig 1) Structure of Losartan

MECHANISM OF ACTION:

The way losartan functions is by preventing the effects of the hormone angiotensin II, which narrows blood vessels. Losartan lowers blood pressure, relaxes blood vessels, and lessens the strain on the heart by blocking the angiotensin II type 1 (AT1) receptor. It is efficient in controlling hypertension and safeguarding vital organs like the kidneys because of this process.

PHARMACOLOGICAL PROPERTIES [8]

 Medication causes LVH in people with hypertension and LVH to regress while lowering systolic and diastolic blood pressure. Angiotensin II's actions are blocked by losartan, a selective, competitive, reversible angiotensin AT1 receptor antagonist. E3174, the active metabolite of losartan, is a noncompetitive, reversible antagonist of the AT1 receptor. In the context of stroke prevention, losartan is a reasonably priced substitute for atenolol and is well tolerated. It would be interesting to know how losartan and other antihypertensive medications compare in terms of clinical outcomes in hypertension patients.

THERAPEUTIC EFFICACY [9]

 The relative effectiveness of losartan in relation to CV clinical outcomes in patients with hypertension has been examined in one investigation.  In several patient groups in LIFE sub study analyses (i.e., patients with isolated systolic hypertension, patients with a history of atrial fibrillation, and patients without clinically evident vascular disease), the incidence of stroke was significantly lower in losartan recipients than in those receiving atenolol. Additionally, there was a lower incidence of CV mortality among losartan recipients. In a community-based research, patients with mild to moderate hypertension who received a systematic losartan-based regimen required less switching to alternative medicine than those who received conventional care. Losartan had a more favourable effect on quality of life than enalapril in elderly patients with hypertension. However, the drug had a similar effect on quality of life to nifedipine GITS, although the total number of adverse events reported with nifedipine GITS was greater than in losartan recipients.

  Tolerability

The elderly individuals with hypertension who took losartan 50 or 100 mg either alone or in combination with low dose hydrochlorothiazide tolerated it well. Approximately 5 to 10% of patients had headache, asthenia, oedema, and upper respiratory tract infections, which were the most frequently reported side effects.  

CLINICAL USES [16,17]

Hypertension:

The main reason losartan is administered is to treat high blood pressure. It works well to lower blood pressure and lower the risk of heart attack, stroke, and other hypertension-related problems.

Symptoms

Most people with high blood pressure have no symptoms, even if blood pressure readings reach dangerously high levels. You can have high blood pressure for years without any symptoms.

A few people with high blood pressure may have:

• Headaches
• Shortness of breath
• Nosebleeds

However, these symptoms aren't specific. They usually don't occur until high blood pressure has reached a severe or life-threatening stage.

Heart Failure:

Heart failure is treated with it, particularly in patients who are intolerant to angiotensin-converting enzyme (ACE) inhibitors.

1. Shortness of breath: This can occur during activity or while lying down.
2. Fatigue and weakness: Feeling unusually tired or weak.
3. Swelling: This can happen in the legs, ankles, feet, or abdomen due to fluid retention.
4. Rapid or irregular heartbeat: Palpitations or a feeling of the heart racing.
5. Persistent cough or wheezing: Often accompanied by white or pink blood-tinged mucus.
6. Increased need to urinate at night.
7. Weight gain: Rapid weight gain from fluid retention.
8. Lack of appetite and nausea.
9. Difficulty concentrating or decreased alertness.

Diabetic Nephropathy: 

Patients with type 2 diabetes who have diabetic nephropathy (kidney disease) benefit from losartan treatment because it helps shield the kidneys from additional harm. Diabetes-related nephropathy is a progressive disease that affects your kidneys. Long-standing diabetes causes diabetes-related nephropathy. Symptoms don’t appear until later stages, but they include swelling, peeing more often, foamy pee, nausea and fatigue. Treatment includes managing your diabetes and blood pressure.

Stroke Prevention:

In individuals with hypertension and left ventricular hypertrophy (thickening of the left ventricle of the heart), the medication may be administered to lower the risk of stroke.

Benefits

Effectiveness Patients with heart failure or diabetic nephropathy benefit from losartan's effective blood pressure-lowering effects and improved prognosis.

Tolerability:

Compared to ACE inhibitors, it is generally well tolerated and has a decreased incidence of cough, which is a common side effect of ACE inhibitors. tolerability of a particular drug can be discussed in a general sense, or it can be a quantifiable measurement as part of a clinical study. Usually, it is measured by the rate of "dropouts", or patients that forfeit participation in a study due to extreme adverse effects. Tolerability, however, is often relative to the severity of the medical condition a drug is designed to treat. For instance, cancer patients may tolerate significant pain or discomfort during a chemotherapeutic study with the hope of prolonging survival or finding a cure, whereas patients experiencing a benign condition, such as a headache, are less likely to.

METHOD DEVELOPED

1. Chromatography (HPLC)
2. LC-MS
3. HPTLC
4. Liquid Chromatography-Mass Spectrometry (LC-MS)
5. UV spectroscopy

Mass spectrometry and liquid chromatography are combined in liquid chromatography-mass spectrometry, or LC-MS. Compounds are separated using HPLC, ionized, and then their mass-to-charge ratio is measured.[5]

High-Performance Liquid Chromatography (HPLC)

Under high pressure, chemicals are separated using High-Performance Liquid Chromatography (HPLC) based on how they interact with a stationary phase and a mobile phase. By examining their various affinities for the stationary phase, losartan and its metabolites are separated and quantified.[4]

CHROMATOGRAPHY [20]

1.Gas Chromatography (GC)

• Compounds are separated using gas chromatography (GC) according to how volatile they are and how they interact with the stationary phase. Due to its relatively low volatility and thermal stability, losartan is less commonly employed; however, it can be used in conjunction with derivatization procedures to evaluate the medication or its degradation products.
• As a result, it is employed in the gas phase to identify and segregate tiny molecular weight molecules. The sample is vaporized in the injection port and can be either a gas or a liquid. Because helium is chemically inert and has a low molecular weight, it is commonly used as the mobile phase in gas chromatography.
• The analyte is moved across the column by the mobile phase when pressure is applied. A stationary phase-coated column is used to achieve the separation. The components of the sample will partition, or disperse, between the stationary phase and the mobile phase in a gas chromatography equilibrium known as partitioning.
• Compared to samples with a higher affinity for the mobile phase, compounds with a larger affinity for the stationary phase elute later and have a longer retention time (Rt) because they spend more time in the column.
• Intermolecular interactions are the primary force behind the stationary phase's affinity, and the stationary phase's polarity can be selected to optimize interactions and, consequently, separation.
• When applied correctly, GC can measure parts-per-billion concentrations in gaseous samples or picomoles of a material in a 1 ml liquid sample.

The field of forensic science makes substantial use of gas chromatography. GC is used in a wide range of disciplines, including paint chip analysis, toxicological cases, arson investigations, solid drug dose (pre-consumption form) identification and quantification, and more, to identify and quantify different biological specimens and evidence from crime scenes.

 Under the influence of a solvent, Thin-Layer Chromatography (TLC) divides substances according to their various speeds of movement on a stationary phase, which is a thin layer of adsorbent material.[7].

• The separation principle is the foundation of thin-layer chromatography (TLC). The relative affinities of the chemicals for the two phases determine the separation. Over the surface of the stationary phase, the compounds in the mobile phase travel. The compounds that have a stronger affinity for the stationary phase move more slowly than the other compounds, with the movement happening in this way. As a result, the mixture has been separated. The mixture's constituent parts emerge as spots at their appropriate levels on the plates once the separation procedure is complete.
• TLC does qualitative testing on a range of medications, including steroids, hypnotics, analgesics, anticonvulsant tranquilizers, sedatives, and local anaesthetics.
• TLC is incredibly helpful in biochemical analysis, including the isolation or separation of biochemical metabolites from bodily fluids like serum, urine, blood plasma, etc.
• Using thin layer chromatography, one can detect natural compounds such as waxes, alkaloids, glycosides, fixed oils, volatile or essential oils, etc. It is frequently employed in the division of complex medicinal compositions. Samples are purified using it, and a direct comparison between the sample and the real sample is made.
• In the food sector, it's utilized to distinguish and identify colouring, sweeteners, and preservatives.

It's employed in the cosmetics business and to determine whether a response is complete.

Disadvantages Of Thin Layer Chromatography:

1. There is no longer stationary phase on Thin Layer Chromatography plates.
2. to alternative chromatographic methods, there is a restriction on the length of separation.
3. It is challenging to duplicate the outcomes of TLC.
4. The chromatogram's ultimate result may be impacted by a number of variables, including temperature and humidity, because TLC is an open system.
5. Since the detection limit is high, TLC cannot be used to achieve a reduced detection limit.
6. It is not a quantitative analysis method; rather, it is merely a qualitative one.

 3. UV Spectroscopy [18]:

The measurement and analysis of electromagnetic radiation emitted or absorbed as molecules, atoms, or ions in a sample transition from one energy level to another is known as spectroscopy. UV spectroscopy is a kind of absorption spectroscopy in which the molecule absorbs light in the ultra-violet range (200–400 nm), which excites the electrons from their ground state to a higher energy state.

Principle of UV Spectroscopy

1. Spectroscopy is essentially concerned with how light interacts with stuff.
2. The energy content of the atoms or molecules increases as light is absorbed by matter.
3. The absorption of UV radiation excites electrons to move from their ground state into a higher energy state.
4. Electrons in molecules called ?-electrons or nonbonding electrons (n-electrons) can be excited to higher anti-bonding molecular orbitals by absorbing energy from ultraviolet light.
5. The longer the wavelength of light that an electron can absorb, the more readily excited it is. Transitions can be categorized into four types: ?–?*, n–?*, ?–?*, and n–?*. They can be arranged in the following order: *\?–?* > n–?* > ?–?* > n–?*

The accuracy of UV-VIS spectrometers is their greatest benefit to chemists and astronomers. When making chemical solutions or tracking the motion of celestial bodies, even tiny UV-VIS spectrometers can provide incredibly accurate measurements. The UV-VIS spectrometers are user-friendly. The majority of astronomical UV-VIS spectrometers are telescope-mounted. The majority of those used in chemistry are about the same size as electron microscopes and operate with similar fundamental knowledge. There is minimal possibility of a UV-VIS spectrometer being utilized incorrectly due to its ease of use.

Disadvantages of UV-VIS Spectrophotometers The primary drawback of utilizing a UV-VIS spectrometer is the amount of time required to get set up. The configuration of UV-VIS spectrometers is crucial. Any external light, electronic noise, or other impurities that can tamper with the spectrometer's reading must be removed from the region. UV-VIS spectrometers are easy to use and produce reliable findings if the area has been correctly set up beforehand. But, if the area isn't set up correctly, even a tiny amount of outside light or vibration from a tiny electronic gadget could skew the results of your UV-VIS spectrometer experiment.

LC-MS[14]

Liquid chromatography–mass spectrometry (LC–MS)

is a method of analytical chemistry that combines the mass analysis capabilities of mass spectrometry (MS) with the physical separation capabilities of liquid chromatography (or HPLC). Coupled chromatography-MS systems are popular in chemical analysis because the individual capabilities of each technique are enhanced synergistically. Mass spectrometry provides spectral information that may help to identify (or confirm the suspected identity of) each separated component, while liquid chromatography separates mixtures with multiple components.[1] MS is not only sensitive, but also provides selective detection, negating the need for complete chromatographic separation.

• Heightened sensitivity, specificity, and precision
• Analysis at the molecular level
• Elucidation of structural characteristics of the analyte
• Improved accuracy and precision
• Better selectivity

Disadvantages of LC-MS

It only works with volatile buffers that are required to avoid fouling of the API interface2

• .It requires the analytes to be ionized, which may not be possible for some compounds2.
• It is not compatible with phosphate buffer, which is commonly used in HPLC2.
• It is an expensive instrument that might not be affordable for some laboratories3
• .It uses collision induced dissociation, which produces fewer ions and is not good for library

LITERATURE REVIEW: