Pressure increases cause slight decreases in peptide bond stability, which are generally offset by greater stability caused by temperature increases along geothermal gradients. These calculations suggest that peptides, polypeptides, and proteins may survive hydrothermal alteration of organic matter depending on the rates of the hydrolysis reactions. Extremely thermophilic organisms may be able to take advantage of the decreased energy required to form peptide bonds in order to maintain structural proteins and enzymes at elevated temperatures and pressures. As the rates of hydrolysis reactions increase with increasing temperature, formation of peptide bonds may become a facile process in hydrothermal systems

apparatus for vacuum distillation with tap water

You could also try to remove the pyridine by washing your crude product with water, provided that your product is not soluble in water. Pyridine is miscible with water. If your peptide is water soluble, you may adjust the pH of the water to make your peptide insoluble.

Advantage of this method is that you do not risk destroying your peptide by exposing it to the high temperature (in air) required to remove the pyridine at atmospheric pressure.

Thank you so much @Goran Benedeković for your suggestion.

Thank you so much @Kothapu GOPAL Reddy for your insights in peptide bonds and stability concern.

Thank you so much @Luc Alders. From your suggestion, I should alter the pH of water using HCl, so it can be called as treating the crude mixture with an aqueous HCl (mild HCl) solution to remove pyridine.

Advice, next time be more precise in asking questions. Your question was in terms of removing pyridine only by distillation method and you did not ask about other methods. I recommend the solution from Luc Alders if your compound is not sensitive to acids and can be extracted with a suitable solvent from water. Always state the nature of your compound in the question, peptides, heterocycles, sugars...etc

@Goran Benedeckovic, Thanks for your suggestion. Even I have pinpointed my compounds nature as peptide in my Question. Please read out my question fully.

unfortunately, on my computer I only see the text you see below. No problem, the important thing is that your problem is solved.

Is it possible to co-evaporate pyridine from the reaction mixture using toluene as an azeotrope in an ambient condition using hot plate?

If not, kindly suggest how to do simple co-evaporation methods if we do not have Rota evaporator.

(Key points - Organic reaction mixture contains peptide crude)

Thanks in advance

Your question as stated is, at best, ambiguous. Please be much more specific which helps to facilitate a useful answer.

You say in the Key Point that the product is a peptide. What type of peptide: dipeptide, oligopeptide? Expected stability ( e g. to heat) of the peptide? What type of apparatus and conditions are being used for solvent removal? Removing solvents, especially pyridine, is almost always done under reduced pressure using a rotary evaporator. Co-evaporating with toluene is best done under reduced pressure. Using a hot plate as a heat source (how?) is not efficient and even if an oil bath is used there could be safety issues. The bath temperature needs to be significantly higher than the bp of toluene-pyridine azeotrope.

Trying to remove pyridine with H2O could be problematic as the peptide could be carried along into the aqueous phase and pH adjustment to decrease solubility may be difficult depending on the amino acid components.