In HP-TLC, each and every parameter that influences the result is controlled

Akshay Charegaonkar, Director, Anchrom Enterprises, talks about the benefits if HP-TLC in an interaction with Express Pharma

What is the background of Anchrom?

My father Dilip Charegaonkar is India’s first full fledged R&D Analyst who worked in Themis Pharmaceuticals from 1976. In 1978, he quit to promote TLC when HPLC started coming in. To this day TLC, instrumental TLC (I-TLC) and High Performance Thin Layer Chromatography (HP-TLC) are irreplaceable, partly because of Anchrom’s dedicated effort. Since the last nine years, me and later my wife have actively joined him, at Anchrom. This year, is the 40th year of our association with Camag, Switzerland who pioneered HP-TLC.

What is unique about HP-TLC?

The sample is literally ‘visible’ throughout. Chromatography is done in independent steps. No high temperature or pressure is involved and is fastest of all chromatography methods. Samples do not come into contact with the chromatograph. Chromatogram retained on plate. Hence, multiple modes of detection can be applied. Samples can be cleaned up on the (disposable) plate.

You mentioned about I-TLC. Is it a new concept?

Instrumental TLC (I-TLC) is halfway between manual TLC and regulatory level HP-TLC. I-TLC has all the advantages of instrumentation but the chromatography methodology is not standardised.

Will HP-TLC replace I-TLC?

HP-TLC is I-TLC + methodology, so it’s not a replacement but an improvement. In HP-TLC, each and every parameter that influences the result is controlled. However, labs in developing countries will use TLC, I-TLC as well as HP-TLC for economic reasons.

Do you have an application lab?

We do. In fact, Anchrom started the world’s first application lab by a distributor. Ever since it started in 1989, every day we do real life samples analysis. Our lab is not a show room. Today, with a little prior discussion and planning, anybody can walk into our lab and we can develop a new method and analyse the sample, entirely new to us, on the same day.

Is that possible only with HP-TLC?

Yes. HP-TLC is a ‘safe’ technique, in which the samples cannot damage the chromatograph. Samples remain always on the separating medium i.e. the plate. So any sample is acceptable. Secondly, changing parameters for new method development is easy and several trials can be done in parallel, using appropriate instrument. HP-TLC is done in four to six independent steps, which makes method development easy. The sample is ‘visible’ throughout the analysis. Silica gel is nearly, an universal stationary phase. Our new method development success rate is >99 per cent in the last 24 years. We are a purely R&D analytical lab.

What is the status of HP-TLC today?

HP-TLC is an official pharmacopoeial method in the US, Europe, India etc. and at WHO. Qualitative, semi-quantitative fingerprints and quantitative analysis are common aims of HP-TLC analysis. HP-TLC-MS hyphenation is official in USP.

Why is HP-TLC considered a costly method?

Not really. HP-TLC requires higher initial investment because even entry level instrument is very sophisticated and capable. It’s incorrect to look only at purchase price. Once purchased, HP-TLC can give the output of 4-5 HPLCs and that too, at a fraction of cost of analysis. Some people wrongly compare HPLC price with HP-TLC. At entry level, HP-TLC is extremely well equipped compared to a skeleton HPLC. Cost per analysis, investment per sample, high sample throughput, negligible maintenance, long instrument life etc. are other factors to consider.

Are you saying HP-TLC is superior to HPLC?

Yes, but only where HP-TLC is suitable, e.g. content uniformity test, monitoring the whole Indian pharma market i.e. bulk screening. HP-TLC can double or triple the analysis output based on chromatography results, of all CDSCO and FDA labs. For materials of botanical origin, HP-TLC is indispensable for identification, quantification of markers and detection of adulteration, all by one single ‘HP-TLC fingerprint’ test. ‘Identification of botanicals’ is a very big issue, elegantly solved by HP-TLC.

Why then we have many labs, using dozens of HPLCs and not HP-TLCs?

HP-TLC became official technique only in late 2015. Many labs have multiple HPLCs, not because they have that many samples but because HPLC is a slow, rigid and service prone technique. Imagine a cargo transport company that relies on rickshaws to move goods. More the goods, more autorickshaws and associated paraphernalia. HP-TLC is like a LCV that carries many different consignments of different shapes. HPLC can be fully automated, which makes it popular in developed countries while developing countries should use HP-TLC wherever possible, for cost effective analysis, particularly for generics.

Is there a lab anywhere in India, where several HP-TLCs are installed?

Such a situation is rarely going to occur. One HP-TLC System can analyse a hundred samples of different type in a shift. Four or five analysts are required to keep one HP-TLC busy. For 200 samples/shift, may be 2 HP-TLCs are required which would require a dozen or two of HPLCs.

Is HP-TLC used in educational institutes?

More than 60 educational institutes have it. We are in the process of installing a large Camag HP-TLC system worth more than a crore rupees at the Bombay College of Pharmacy, for research activities.

How does HPLC compare with HP-TLC?

They are two different but complimentary techniques. Each has its advantages and limitations. There is no reason for comparison.

How do you see the future of HP-TLC?

Wear your goggles! Jokes apart, the future is very bright. HP-TLC is a new technique that is simple, high throughput, visible, low analysis cost and little maintenance. Smarter the analyst, sooner will be the purchase of HP-TLC in that lab. But you need to follow USP Chapter 203 SOP, for great results. Being flexible, HP-TLC is equally useful in R&D and QC. The implications of being an official method will be very visible from the next two to three years.

Already about 500 labs use HP-TLC in India. Our lab will now systematically develop new India-specific methods of analysis.