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• Oral liquids


  Homogeneous liquid preparations, usually consisting of a solution, an emulsion, or a suspension, of one or more active ingredients in a suitable liquid base
• Oral liquids


  • Prepared for oral administration either as such or after dilution
  • May contain other substances such as suitable dispersing, solubilizing, wetting, emulsifying, stabilizing, suspending, and thickening agents and antimicrobial substances for preservation
  • May also contain suitable sweetening agents, flavoring agents, and permitted coloring agents
• QC Tests for Solutions

  • Appearance Test
  • Physical tests
  • Chemical tests
  • Stability Test

  
• Visual Inspection


  • Inspect the solution. It should be clear and free from any precipitate. Discoloration or cloudiness of solutions may indicate chemical degradation or microbial contamination
  • Inspect the suspension. Evidence of physical instability is demonstrated by the formation of flocculants or sediments that do not readily disperse on gentle shaking. Discoloration may indicate chemical degradation or microbial contamination
  • Inspect the drops. Drops that are solutions should be clear and free from any precipitate. Evidence of physical instability of drops that are suspensions is demonstrated by the formation of flocculants or sediments that do not readily disperse on gentle shaking. Evidence of physical instability of drops that are emulsions is demonstrated by phase separation that is not readily reversed on gentle shaking. Discoloration (or cloudiness of solutions) may indicate chemical degradation or microbial contamination of the drops
  • Inspect the granules. Evidence of physical instability is demonstrated by noticeable changes in physical appearance, including texture (for example, clumping of granules, presence of loose powder). Discoloration may indicate chemical degradation or microbial contamination

  
• Physical tests


  • Appearance, clarity and colour of solution
  • pH
  • Viscosity (Viscosity is a measure of a fluid's resistance to flow)
  • Crystal modification or particle size (Particle Size Determination or particle measuring, using test sieves entails the passing of particles through screens (sieves) of ever decreasing size)

  
• Chemical tests


  • Assay
  • Degradation products
  • Related substances
  • Residual solvents
• Specific Gravity (for suspensions and syrup)


  Decrease in density indicates the presence of entrapped air. It can be determined with density bottle or hydrometer.
• Rheological Studies


  The viscosity can be determined with Brookfield or Cone and plate Viscometers. Rheologic Property is a test for flowability [fluidity] and viscosity.

  
• pH Determination


  It can be determined with pH meter
• Zeta Potential


  Zeta potential has practical application in the future stability of systems containing dispersed particles since this potential governs the degree of repulsion between the adjacent similarly charged dispersed particles. A higher zeta potential is more desirable because suspensions tend to have a slower rate of settling.

  
• High sugar concentrations cause the bacterium to lose water by osmosis and it doesn't have any cellular machinery to pump it back in against the osmotic gradient. Without enough water, the bacteria can't grow or divide.
• Alcohol Meter


  Used to measure the Proof of your distilled product

  
• Sedimentation Volume (F)


  The ratio of the ultimate volume (Vu) of the sediment to the original volume (Vo) of the suspension. F=Vu/Vo. The larger this ratio, the better is the redispersibility.

  
• Flocculation


  A process by which a chemical coagulant added to the water acts to facilitate bonding between particles, creating larger aggregates which are easier to separate.
• Redispersability Test


  It refers to the amount of force to redisperse or resuspend the particles. The requirement is that no sediment should remain at the base after shaking.
• Redispersibility


  The ease of redispersion of the formed sediment by moderate shaking to yield a homogenous system. It can be determined either by simple agitation of the suspension in the container or the use of a mechanical shaking device which stimulates human arm motion during the shaking process and can give more reproducible results.

  
• Particle Size Changes


  Any change in the particle size of the suspension can give an indication of crystal growth. The freeze-thaw cycling technique is applicable to stress the suspension to promote crystal growth and the particle size can be measured by using microscope, Coulter counter device, or laser diffraction device. Suspension must be firstly diluted and deflocculated to ensure that each individual particle is measured rather than each floccule. This method indicated the probable future state of suspensions after long storage at room temperature. The freeze–thaw process represents a "mild" homogenization procedure and it is usually used in combination with other homogenization methods. It consists of quickly freezing at −85°C and thawing at 4°C in sequence (the tubes could be thawed quickly at 6–10°C in a water bath for 10 min and kept at 4°C). The Coulter counter uses the principle that the electrical resistance of a conducting liquid is increased by the addition of an insulating material. Particles are assessed individually. To obtain adequate sensitivity, the volume of liquid measured must be similar to the volume of the particle.

  
• Emulsion Type Test


  When a filter paper soaked in cobalt chloride solution is dipped into an emulsion and dried, it turns from blue to pink, indicating that the emulsion type is o/w type. Spreading test: water in oil type emulsion spread on the surface of oil but not on the surface of the water.
• Appearance


  The general appearance of a granule, its identity and general elegance is essential for components in manufacturing, for control of lot-to-lot uniformity and tablet-to-tablet uniformity. The control of general appearance involves the measurement of size, shape, color, presence or absorbance.
• Compressibility


  Density may influence compressibility, tablet porosity & dissolution. Dense hard granules may require higher load to produce cohesive compact to reduce free granules seen on the surface of tablets. Increased compressibility leads to increased disintegration time (DT) and dissolution, if DT is slower dissolution is indirectly hampered. Dense granules have less friability but cause a problem in releasing the drug.
• Compressibility Index


  It is directly related to the relative flow rate cohesiveness & particle size. It is simple fast & popular method of presiding powder flow characters.

  
• Hausner Ratio


  It is used to predict the flow property of powder by using inter particle friction. It showed that powder with low particular friction such as coarse sphere had ratio of approximately 1.2, whereas more as cohesiveness- less free flowing powders such as flaks have Hausner's ratio greater than 1.6.

  
• Porosity


  The property of an object that expresses the total volume of empty or pore space in the material.
• Cup Method


  The cup method is performed by seeding a solid medium with a test organism and filling antibiotic in cups on or in the medium. It is then placed in the incubator. During the growth of the organism the antibiotic will diffuse into the medium so that its concentration will decrease with increasing distance from the cup. The test organism cannot grow where the concentration exceeds a certain level and consequently, after completion of the growth, inhibition zones without colonies will appear around the cups. The diameter of inhibition zones will increase with increasing strength of the antibiotic solution and may consequently be used for estimation of the antibiotic concentration.
• Microbiological Assay of Vitamins

  The microbiological assay of vitamins is based upon the comparison of the stimulation of growth of bacteria by measured concentration of vitamin with that produced by known concentration of standard preparation of Vitamin having known activity.