Oral solid forms are more stable than all the dosage forms which are manufactured in pharmaceutical industries.OSD is the abbreviation of oral solid dosage form which is commonly used to represent oral solid dosage form.OSD or oral sole dosage forms are prepared in pharmaceutical industries by using different methods like wet granulation method,dry granulation method and direct compression or direct mixing process.
The main examples of the dosage form which come under oral solid dosage forms are the tablets, capsules, dry powder suspension,dry powder sachet.
Blending Process
The blending process is one of the most important steps which is performed for the manufacturing of oral solid dosage forms and to perform this blending process different types of blenders or mixing equipment are used.
The main examples of the mixing equipment or blenders which are used for the blending purpose are double cone mixer, bin blender, V shaped mixer, plough mixer or high shear mixer. These are some commonly used equipment which are the main examples of the equipment used for the blending process.
Purpose Of Blending
The purpose of blending is to prepare the uniform blend of the solid materials.We use the process of mixing or blending where two or more solid materials are mixed with each other to ensure the uniformity of the blend or to prepare a mixture of solid materials which is uniform in content and uniformity.
In simple words the blending process is done to make a uniform blend which gives us assurance that our mixed blend is compliant with the requirements of content uniformitya and assay.
Explanation
For easy understanding of the
blending process Let’s start from the example of tablet manufacturing where we use the blending process for the mixing of different types of excipients and active pharmaceutical ingredients to ensure the content uniformity and assay value of the powders or granules.
Suppose we are going to prepare the batch of tablets by wet granulation process where the blending process is used twice, meaning one is known as pre blending process and second one is known as final blending process.
Pre Blending Process
The pre blending process, as the name indicates, is the process which is used for mixing or blending of the excipients and active pharmaceutical ingredients before granulation, wetting or kneading stage.
Why do we need pre blending? We need pre blending step to ensure that all the excipients and active pharmaceutical ingredients are uniformly mixed before carrying out the kneading stage and due to the pre blending process our powder mix contains uniform quantity of all the excipients and active pharmaceutical ingredients.
Example
Suppose we are going to manufacture a batch of tablets and we are using excipients like starch, lactose and active pharmaceutical ingredient e.g metformin at the pre-mixing stage.
We will take all the excipients and active pharmaceutical ingredients & will mix all these excipients and API in a blender or rapid mixing granulator to ensure a uniform blend of the excipients and active pharmaceutical ingredients.
For this we will take lactose, starch,metformin and will add these materials into the blender or mixer and will mix to the time period mentioned in the batch manufacturing record.
Pre blending process is very important to get the desired uniformity of the material and contents before the wetting or kneading stage.
Final blending process
The final blending process, also known as post blending, means we perform this blending activity at the last stage of granulation process after the dry sieving of the granule.
Why Post Blending
Post blending or final blending process ensures the content uniformity of the final product means our batch is manufactured & ready for compression with the built in assurance that assay value & content uniformity will be as per specifications.
During the post blending or final blending process we mix our all remaining excipients or active pharmaceutical ingredients with the granules.
Examples Case 1
Take the example of above mentioned granules which were prepared by the pre blending of lactose,starch and metformin.
Now we will mix these granules with remaining excipients like disintegrants, glidants and lubricants by using a blender like a double cone blender.
We will add all the granules in a double cone blender & mix with disintegrant for the time period mentioned in our batch manufacturing record.
After completion of blending with disintegrants we will add other excipients e.g glidants.We will add glidants in a blender and will mix with granules which were previously mixed with disintegrants.
Now we will add lubricants & one key factor to remember is to add lubricants at the end of all the excipients and mix for the time period mentioned in BMR.
Example Case 2
Final blending process is also used where we have to mix active pharmaceutical ingredients in the final blending stage.It is done where we have two or more active pharmaceutical ingredients and use one or two active pharmaceutical ingredients in pre blending stage and the remaining are added in the final blending process.
Here the same process is followed where we add our granules in the blender and mix them with the remaining active pharmaceutical ingredients and then we mix these with disintegrants & later with glidants and lubricants for the prescribed time.
So we perform the final blending or post blending process to ensure the uniformity of our blend and it ensures that our essay value and content uniformly of the product will be within the prescribed ranges.
Conclusion
The blending process or blending stage is very important for manufacturing of oral solid dosage forms where we mix different types of solid materials with each other depending upon the formulation.
Without the blending process, the mixing of excipients & active pharmaceutical ingredients will not be uniform and it will result in failure of content uniformity and assay value so our batch will not be released by quality control and will not be fit for use.
To ensure the compliance with content uniformity and assay value the blending process is performed & monitored critically in pharmaceutical industries for manufacturing of oral solid dosage forms.
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