a Test For Uniformity For Weight Of Tablets
This is a vital assessment carried out qualitatively to warrant that every single tablet has the quantity of drug substance that meets the specifications set by the manufacturing and pharmacopoeia law. It also foresees that the quantity of drug substance needed has less variation among the tablets that are within a batch. However, this test does not include the tablets and capsules needed to adhere to with the uniformity of content test. The main objective of this experiment is to make certain that the uniformity of tablets fulfil the quality set by pharmacopoeia and this is done determining the deviation percentage of tablets and capsules (Choudhary and Pawar, 2014). The weight test of uniformity has been placed in the monographs of all tablets administered orally due to increased consciousness of physiological availability.
This test makes sure that the patient gets the right dosage in tablet to ensure there are no toxic effects. This test is carried out by manufacturers in the pharmaceutical sector to ensure that the produced tablets are fit the standards set by the law and are fit for human consumption(Solanki and Dahima, 1970) . If the drug components are not evenly distributed they may alter they can cause problems in the patient such as unable to reach a range of therapy or maybe can be excess causing toxicity to the patient.
TABLET HARDNESS TESTING
Test for tablet testing is defined as the pressure force needed to break a tablet in a compression test. This is a method in the laboratory that is useful in the pharmaceutical sector as it determines a tablets structural integrity and its breaking point. The hardness of a tablet plays a role as the basis of quality control that regulates product development. This is because tablets are not supposed to be too hard or too soft. This test is used in conjunction with friability test play and it plays an essential role in the drug production and overall quality determination (Blanco and Alcalá, 2006) . This test came into sight in the 1930s afterwards the Strong-Cobb tester was introduced in 1950s and this utilized an air pump. The breaking force of a tablet was established on arbitrary units which were referred to as strong-Cobbs. Subsequently, the electro-mechanical test was launched.
This is associated with techniques such as the ability to send measurements to a printer or computer and motor drives.This method is a vital feature in medical science. Challenges in ensuring that thickness, tablet hardness and weight of tablets are common. There are two mechanisms applies in this test this is the compression test and three-point bend test. Compression test involves the alignment of a tablet in a repetitive manner and this tablet is squeezed in the middle of a fastened and moving jaw. The tablet is set on either side of the two jaws one of which is linked toa motor and the other toa jaw cell. The test involves the pressing of the tablet averse to the fixed jaw until the tablet breaks. The motorized jaw withdraws and the load needed to shatter the tablet is recorded(May et al., 2013). Force of tactful and it usually needs the lowest level of forces. Sometimes the tablet squeezed by the heaviness of the punch.
Distortion at the punch tip can be caused by excess carriage consequently altering the required analytical working length, as a result, the tablet consistency is virtually impossible. Breakage at the tip is common and can destroy extra tablet press and punches which are usually the fed frame. Punch modification involves shortening of the punch tips and doing away with the lower punch relief.
This condensation of the tip was done directly to their minimum length ensure that the tip is build up and subsequently increases the compression force(Kuentz and Leuenberger, 2000). There is the removal of the lower punch tip relief to decrease the clearance of that is in the middle of the die bore and the tip stem this supplies extra support at the tip of the stem leading to decreased alteration. When the length of the tip is decreased the barrel length is made bigger, as a result, the die bottom is weakened to receive the extended barrel for the elimination of the tablet.
High levels of hardness are displayed by values such as raised disintegration times and decreased dissolution rates (Seitz and Flessland, 1965) . However low hardness of the tablets indicates that friability is low and as a consequence level of defectiveness is as well high. Well-done research on the relationship between aspects such as dissolution, friability, variation in weight, level of defectiveness and hardness can be employed in the production of the dosage form with the standards characteristics
Importance of tablet hardness test
There several reasons as to why this test is usually carried out, the following gives an outline of the importance of this test.
-This test is vital in analyzing properties in tablets such as:
- The capacity to tolerate mechanical strains during various situations such as storage, shipping, packaging, delivery and handling by the user.
- The relation with solubility.
- A crucial framework in the quality control of tablets.
-it helps to determine the tablet disintegration because an excessively hard tablet has a lot of bonding capabilities between its excipients and active ingredients which can block the required breakdown of the tablet needed for the right dosage form. On the other hand, a soft tablet shows that bonding is weak and may cause premature dissolution when the patient consumes it.
-It determines to handle of the tablets because a soft tablet may not support proper handling by the user and could result in cracking or chipping the final phases of production. Examples of these are packaging and coating during transportation.
-It determines the material ingredients. Knowledge in the mechanical characteristics of a tablet dosage form gives essential information required to check the material ingredients. Aspects such as material ingredients, the binder used and the chemical composition of the samples used in the tablet affect the hardness of the tablet.
-It determines the process of production. Information on the correct tablet press speed, flow of granulation and powder air is crucial in making the correct dosage form. Regulating these factors is important in the production and manufacturing of a tablet with the right and suitable hardness.
Advantages of tablet hardness test
- It gives information about the drug if it’s able to withstand various situations such as storage, handling, shipping and packaging.
- It saves time and money by determining the appropriate process of production of the drug.
- It provides knowledge in the disintegration of the drug which helps in quality control to ensure the drug produced is fit for human consumption
Disadvantages of tablet hardness tests.
- It is not always accurate as a single mistake resulting in errors in the hardness date.
- In order to achieve accurate results, the location of the test must be free from contamination.
- When hardness increases ut becomes hard to carry out the tests.
FRIABILITY TEST FOR TABLETS.
Friability can be defined as the probability of a soli\d substance to break smaller pieces most commonly by rubbing. This is a technique tests the capability of tablets to last during packaging and transport(Mohapatra, Parikh and Gohel, 2008) . This test involves dropping a sample of Tablets repeatedly over a fixed time and it utilizes a rotating wheel fitted with a baffle. The values obtained are then evaluated for broken tablets and the percentage of the mass lost due to chipping including the zero broken tablets (Kapoor et al., 2017).
The hardness of tablets is essential to ensure that they do not break during handling but can be friable enough to be broken down in the gastrointestinal;l tract once taken by the patient. This test has been fully absorbed as an accepted standard in the pharmaceutical sector in control of the resistance of uncoated tablets to scraping and the shock that occurs during production, packaging and shipping procedures (Osei-Yeboah and Sun, 2015)
Test for disintegration on tablets
This test is carried to determine whether tablets are able to breakdown into smaller particles within a prescribed period of time when placed in a liquid medium under prescribed experimental conditions (Ahmed, Shamma and Shoukri, 2011) . It refers to the evaluation of the duration of time required under a set of conditions for tablets to breakdown into small particles that will be able to pass through a 10 mesh screen. It is an important quality assurance technique for standard dosage forms. In order for a given solid dosage for administered orally to be completely absorbed it should be placed in a fluid medium so that breakdown can occur and thereafter absorption.
Disintegration consists of fragments produced as a result of the breakdown of the tablet and include components such as the insoluble coat of the tablet(Hirani, Rathod and Vadalia, 2009) . Disintegration means that a resistance of the tablets is not left or some of the components above may be left. At times disintegrants can be added to enable the tablet dosage form breakdown when in contact with a fluid(Narazaki et al., 2004) . The cat by softening the dosage form matrix, as a result, ensuring disintegration by various mechanisms. This test includes immersing tablet in a medium with the prescribed experimental conditions and the time taken for the disintegration ios recorded. This time taken by a tablet to disintegrate is known as the applicable monograph(Garg and Gupta, 2013) . The UniteStates Pharmacopoeia defines total disintegration as the condition in which all the unit residues except fragments of the insoluble tablet coating are left in the test apparatus or are attaching to the lower surface of the discs(Klancke, 2003) .
Advantages of disintegration tests
- It produces solid dosage forms that have better stability.
- The drugs that have undergone the test have an easier production process
- The drugs have smaller packing size and are more convenient for handling by the patients.
Disadvantages of disintegration tests
This test cannot be depended on for the bioavailability assurance.
HIGH-PERFORMANCE LIQUID CHROMATOGRAPHY PRINCIPLES.
This is a method applied in analytical chemistry in identification, separation and quantification of every component in a mixture(Danilewicz, 2011). It is also referred to as high-pressure liquid chromatography. It works basically on the principle of partitioning the samples between the stationary phase and the mobile phase. Molecules are then separated because they have different partition coefficient(Walton, 1981) . This method uses a column which holds the picking material which is the stationary phase and a pump that is used the mobile phase through the column and a detector to display the times the molecules have been retained. The pump is utilized in pushing the solvent through the column and a detector in a flow-through the cell that measures the separated peaks(Davankov, 1989).
The principal of HPLC depends on the type of chromatography used. The following are the types of HPLC chromatography and the principals they use.
- Reverse-phase chromatography.
It has a non-polar stationary phase and a moderately polar mobile phase which is aqueous. It operates on the principle of hydrophobic interactions that are as a result of repelling forces between non-polar sample, polar eluent and non-polar stationary phase.
- Normal Phase Chromatography.
This technique operates on the principle that separating analytes based on polarity. It utilizes a mobile phase which is non-polar and a stationary phase which is polar. When the non-polar analyte and polar stationary phase interconnect there is increased elution time period because of increased adsorption strengths.
- Size Exclusion Chromatography.
This is referred to as gel permeation chromatography and it operates by separation of components base on their sizes and in some cases based on their molecular weight. Usually applied in macromolecules including proteins and industrial polymers. Larger compounds have access to a smaller volume and this leads to small solutes being left in the pores for a longer duration of time as compared to larger molecules.
- Ion Exchange Chromatography,
Ion exchange chromatography its principle is retention. It operates by the attraction between the charged molecules found in the stationary phase and solute(Fekete et al., 2015). Similarly charged molecules are excluded. this type of chromatography is used in water purification.
- Bio-affinity Chromatography.
This type of chromatography works on the principle of interaction between proteins and column bound ligands and these interactions are specific and reversible. The proteins can be eluted through biospecific elution and aspecific elution when bound to the affinity column. In biospecific elution, a free ligand in the elution buffer is included and it competes with the ligand-bound in the column. however, in aspecific elution, a difference in aspects such as pH and salt results in weakening the interactions between analyte bound to the column and the protein. Bio-affinity chromatography exhibits high standards of purification in one step.
Dissolution tests principles
The most common method of drug administration is the oral route because of its convenience in delivery to the patient. The swallowed drug releases the active ingredients which are crucial in making sure the drug has been delivered properly. Dissolution rate is the rate at which the drug is released. All drug forms have a dissolution rate. Dissolution testing is used in the pharmaceutical industries to provide crucial in vitro drug information for regulating quality. This quality control processes include assessing batch to batch consistency of solid oral dosage forms such as tablets.
Dissolution test evaluates the rate of the release of drugs and is essential in characterizing the performance of solid dosage forms that are orally administered. Dissolution of a tablet is a regulatory method for evaluating the rate at which a drug is released from a dosage form and all the apparatus used should produce equal results under the same parameters.
The principles of dissolution therefore include :
- The drugs produced are routinely assessed to ensure quality production and uniformity.
- Where applicable prediction of in-vivo is utilized.
- The therapeutic efficiency of the drug is optimized during drug production and manufacturing to ensure proper stability assessment.
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