INTRODUCTION:

Pioglitazone Hydrochloride belongs to the class of thiazolidinediones. Chemically it is (±)-5-[p-[2-(5-ethyl-2-pyridyl) ethoxy] benzyl]-2, 4-thiazolidinedione monohydrochloride¹Fig.1. Pioglitazone Hydrochloride is as a potent and highly selective agonist for the peroxisome proliferator activated receptor-gamma (PPAR). It improves insulin response to target cells with increasing the pancreatic secretion of insulin. Literature survey revealed HPLC^2,3,5, HPTLC⁶, Colorimetric⁴ and UV methods in bulk drug and pharmaceutical dosage forms. The aim of present work is to find out a simple, economical method for the estimation of pioglitazone hydrochloride.

MATERIALS AND METHODS:

MATERIALS:

Standard gift sample of pioglitazone hydrochloride was provided by M/s. Aarti Drugs Ltd., Mumbai, India. The pharmaceutical dosage forms (tablets) - Pioglar-Ranbaxy (30 mg), PATH – Lupin (30 mg), were purchased from local market, TLC precoated aluminium plates with Silica Gel (E Merck).

Solvents Used Analytical grade glacial acetic acid (Merck), perchloric acid 0.1M, mercuric acetate, crystal violet 0.1% (in acetic acid) as indicator, ethyl acetate, toluene.

METHODS:

TLC fingerprint profile of Anti diabetic drug Pioglitazone Hydrochloride:

Thin layer chromatography of pioglitazone hydrochloride formulation and standard pioglitazone hydrochloride was carried out on TLC aluminium plates, precoated with silica gel 60F 254 (layer thickness 0.25 mm) using different organic solvent systems. Pioglitazone hydrochloride formulation and standard pioglitazone hydrochloride were dissolved in methanol and subjected to TLC using toluene: ethyl acetate: glacial acetic acid (50:50:0.2) solvent system as mobile phase. The plates were visualized in the UV short (254 nm) and also treated with Iodine vapours and starch solution. The R_f values of spots were calculated by using the following formula.

R_{f =}Distance from origin to center of spot

Distance from origin to solvent front

Non-aqueous Titration of Pioglitazone Hydrochloride in Pharmaceutical Formulations:

Tablets of Pioglitazone Hydrochloride:

In order to determine the average weight, 20 tablets were accurately weighed and crushed. 30 mg equivalent amount was accurately weighed, transferred to a 250 mL conical flask and 40 mL glacial acetic acid and 10 mL mercuric acetate and 5 drops of indicator were added. In order to determine the percentage, solutions were titrated with perchloric acid 0.1M until color change, which indicates the final point was reached.

Validation of method⁷:

Accuracy:

The accuracy was determined by adding amounts of reference substance to the samples. Equivalent of 30 mg pioglitazone hydrochloride in tablets was spiked with amounts of reference standard and was dissolved in 40mL of glacial acetic acid. Finally this sample was titrated with 0.1M perchloric acid to quantify. Results given in Table 1.

Precision:

The precision of this method was determined for intra and inter day on three different days. The precision was expressed as the percent coefficient of variation. The analysis of variance is an important tool to verify the internal validity of an analytical procedure. Results given in Table 2.

Fig.1: Chemical Structure of Pioglitazone Hydrochloride

Table 1: Accuracy (Recovery Studies) of Pioglitazone Hydrochloride Formulations by the proposed procedure (n=3)

Formulation

Amount of drug added

(mg)

Amount Recovered

(mg)

Percentage

Recovery

(%)

% CV

Formulation1 (Pioglar)

29.94

99.82

0.050

Formulation 2 (Path)

29.82

99.41

0.055

Table 2: Precision (Intra day and Inter day) (n=3)

	Day 1	Day 2	Day 3	Mean interday
Trial I (%)	99.93	99.09	100.21
Trial II (%)	99.86	99.94	99.96
Trial III (%)	99.72	100.02	99.84
Mean	99.83	99.68	100	99.83
SD	0.106	0.515	0.188	0.160
%CV	0.10	0.15	0.18	0.16

SD = Standard deviation; %CV = Coefficient of Variation

Table 3: Thin Layer Chromatography of Pioglitazone Hydrochloride Standard and Formulations

[Mobile Phase – toluene: ethylacetate: glacial acetic acid (50:50:0.2)]

Treatment	R_f Value
Treatment	Pioglitazone Hydrochloride (Standard)	Formulation I	Formulation II
Iodine Vapour	0.623	0.623	0.628
Starch Solution	0.623	0.623	0.628

RESULTS:

TLC fingerprint profile of Pioglitazone Hydrochloride formulations:

The TLC fingerprinting of pioglitazone hydrochloride formulations and standard pioglitazone hydrochloride showed different bands, summarized in Table 3. When compared with pioglitazone hydrochloride, the R_f value 0.62 confirmed the presence of pioglitazone hydrochloride in formulation (Fig. 2 and Fig. 3).

Non aqueous Titration of Pioglitazone Hydrochloride in Pharmaceutical Formulations:

The standard deviation and the coefficient of variation were found to be less than 2%, indicating good repeatability of the non-aqueous titration. The relative standard deviation observed was approximately 0.16%.

The accuracy may be expressed as percent recovery by the assay of known, added amounts of analyte. The mean absolute recovery test of non-aqueous titration was 99% and can indicate a good accuracy.

A) (B)

Treatment with Iodine vapours

(toluene: ethyl acetate: glacial acetic acid - 50:50:0.2)

A = Reference (R) and Formulation I (S₁)

B = Reference (R) and Formulation II (S₂)

Fig. 2: TLC profile of Pioglitazone Hydrochloride (R) and in its formulations (S₁ and S₂)

DISCUSSION:

The reaction between pioglitazone hydrochloride and a nonaqueous medium and glacial acetic acid is an acid-base reaction where the strong acid can donate a proton to nitrogen. The proposed analytical method in a nonaqueous medium shows to be an important tool for precision and accuracy in the quantification of pioglitazone hydrochloride raw material and tablets.

(C) (D)

Treatment with Starch Solution

(toluene: ethyl acetate: glacial acetic acid - 50:50:0.2)

C= Reference (R) and Formulation I (S₁)

D= Reference (R) and Formulation II (S₂)

Fig. 3: TLC profile of Pioglitazone Hydrochloride (R) and in its formulations (S₁ and S₂)

The accuracy may be expressed as percent recovery by the assay of known, added amounts of analyte. The mean absolute recovery test of non-aqueous titration was 99% and can indicate a good accuracy.

The non-aqueous titration is clearly the least expensive method and it does not require high cost equipment and specialized technician when it is compared with spectrophotometric analysis, HPLC. Besides, another characteristic of this method is the short time required for performance and ease of handling that could indicate this procedure as a laboratory routine method.

This volumetric method proposed is simple, rapid and inexpensive and can therefore be applied to the determination of pioglitazone hydrochloride raw material and tablets. Method validation yielded good results.

CONCLUSION:

An inexpensive, simple, precise and rapid method for the determination of pioglitazone hydrochloride in tablets is described. The procedure is based on the use of volumetric dosage in a non-aqueous medium in glacial acetic acid with 0.1 M perchloric acid. The method validation yielded good results and included the precision, recovery and accuracy. It was also found that the excipients in the commercial tablet preparation did not interfere with the assay.

The proposed analytical method in a nonaqueous medium shows to be an important tool for precision and accuracy in the quantification of pioglitazone hydrochloride raw material and tablets.

The accuracy may be expressed as percent recovery by the assay of known, added amounts of analyte. The mean absolute recovery test of non-aqueous titration was 99% and can indicate a good accuracy.

ACKNOWLEDGEMENTS:

The authors would like to acknowledge the regular counsel and guidance of Professor C.V.S. Subrahmanyam, Principal, Gokaraju Rangaraju College of Pharmacy, Hyderabad, India.

REFERENCES:

1. The Merck Index; an Encyclopedia of Chemicals, Drugs and Biologicals; 13^th edition; published by Merck Research Laboratories Division of Merck and Co; INC. White House Station, NJ, USA.,2001,1335

2. Sadaf Sayed. RP-HPLC method development for determination of pioglitazone hydrochloride from tablets, Journal of Pharmacy Research, (2009), 2(9),1479-1480.

3. Wanjari D.B., Stability indicating RP-HPLC for the determination of pioglitazone from tablets, Indian Journal of Pharmaceutical Sciences, 2005,vol.67(2) March-April,256-258

4. Mehta R.S., UV-Visible spectrophotometric analysis of pioglitazone hydrochloride in bulk and tablets,Indian Journal of Pharmaceutical Sciences, 2005,vol.67(4)July-August,487-489

5. Smitha Sharma, et al. study of stress degradation behavior of pioglitazone hydrochloride in bulk and pharmaceutical formulation by HPLC assay method, Journal of Optoelectronics and Biomedical Materials, 2010,vol.1(1), March,17-24

6. Meeta A Jiladia. A simple and sensitive HPTLC method for estimation of pioglitazone in bulk and tablet dosage forms, Asian Journal of Research in Chemistry, 2009,2(2), April-June,207-209

7. ICH Harmonized Tripartite Guideline Validation of Analytical Procedures: Text and Methodology Q2(R1) Current Step 4 version Parent Guideline, 1994, 27 October.

Received on 20.10.2011 Modified on 11.11.2011

Asian J. Research Chem. 4(12): Dec., 2011; Page 1895-1897