Development and Validation of a RP-HPLC Method for Determination of Cyclosporine in Capsule

1. Davis SN, Granner DK. Insulin, oral hypoglycemic agents and the pharmacology of the endocrine pancreas. In: Hardman JG, Limbird LE, Gilman AG, editors. Goodman and Gilman’s The Pharmacological basis of therapeutics, 10th ed. McGraw-Hill; 2001. p. 1706. 2. Koltea BL, Rauta BB, Deoa AA, Bagoola MA, Shinde DB. Liquid Chromatographic method for the determination of rosiglitazone in human plasma. J Chromatogr B 2003;788:37-44. 3. Muxclow AM, Fowles S, Russel P. Automated HPLC method for the determination of rosiglitazone in human plasma. J Chromatogr B Biomed Sci Appl 2001;752:77. 4. Radhakrishna T, Satyanarayana J, Satyanarayana A. Simultaneous spectrophotometric estimation of rosiglitazone maleate and glimepiride in tablet dosage forms. J Pharm Biomed Anal 2002;29:873. 5. Jingar JN, Rajput SJ, Dasandi B, Rathnam S, Development and validation of LC-UV for simultaneous estimation of rosiglitazone and glimepride in human plasma. Chromatographia 2008;67:951-5. 6. Gayatri S, Shantha A, Vaidhyalingam V, Aruna A, Niraimathi V. Development of RP-HPLC method for simultaneous estimation of rosiglitazone and gliclazide in tablet dosage form. Indian Drugs 2004;41:374. 7. Rathinavel G, Umanath U, Valarmathy J, Samueljoshua L, Thanuja S, Ganesh M, et al. RP-HPLC method for the simultaneous estimation of rosiglitazone and gliclazide in tablets. Eur J Chem 2009;6:1188-92. 8. Gayatri S, Shantha A, Vaidhyalingam V. Simultaneous HPTLC determination of gliclazide and rosiglitazone in tablet. Indian J Pharm Sci 2003;65:663. 9. Goyal VK, Kulkarni AS, Dhabale PN. Simultaneous spectrophotometric estimation of rosiglitazone maleate and gliclazide in pharmaceutical tablet dosage form. Asian J Res Chem 2009;2:353. TABLE 2: VALIDATION PARAMETERS Parameter Value

Cyclosporine is an immunosuppressant drug used in post allogenic organ transplant to reduce the activity of patient's immune system [1] .It is a cyclic non ribosomal peptide of 11 amino acids, with molecular weight 1202.61.Its molecular formula is C 62 H 111 N 11 O 12 , and chemically designated as The important property of cyclosporine is its ability to inhibit the production of cytokines, which are involved in regulation of T-cell activation.Particularly it inhibits the synthesis of interleukin 2(IL-2) at the level of gene transcription [2] .This activity is achieved by complex formation with cyclophilin, which leads to reduced function of effector T cells [3] .A literature survey regarding quantitative analysis of cyclosporine revealed that attempts were made to develop analytical method using HPLC, LC-MS [4] and RP-HPLC.The present study was attempted to develop a method of short run time, simple solvent system, and better peak shape with good resolution.and improves resolution [4][5][6][7][8] .HPLC grade water was obtained by double distillation and purifi cation through milliQ water purifi cation system.
ACN of HPLC grade was taken as mobile phase in combination with TFA buffer.To the 1000 ml of milliQ water 0.1 ml of TFA was added and its pH was adjusted to 1.4 with acetic acid.For the preparation of stock, 500 mg of standard was accurately weighed and dissolved in 20 ml of mobile phase (TFA/ACN, 1:1) and was sonicated for 5 min.Standard solution was further taken in 10 ml volumetric fl ask and diluted in a manner to obtain the fi nal concentration of 50 µg/ml.Sample was prepared by cutting 5 gelatinous capsules of Panimun Bioral.In 25 ml of mobile phase, 250 mg accurately weighed capsule content was dissolved.To obtain the sample concentration of 100 µg/ml in mobile phase, 0.1 ml of the sample solution was taken in 10 ml volumetric fl ask and diluted up to the mark with mobile phase.
A reverse phase XTerra C 18 column at 50° was equilibrated with mobile phase (0.1% TFA, ACN) in an isocratic run (20:80).pH was adjusted to 1.4 using acetic acid and fl ow rate was maintained at 1 ml/min.Total run time was 10 min and effl uents were monitored at 210 nm.Sample was injected using 20 µl fi xed loop.
Appropriate aliquots of cyclosporine stock solutions were taken in different 10 ml volumetric fl asks and diluted up to the mark with mobile phase to obtain the final concentration of 5, 10, 15, 20, 25 µg/ml.Duplicate injections using 20 µl fixed loop were made and chromatograms were recorded at 210 nm.
Quantifi cation was carried out by keeping peak area and concentration of drug to straight line equation and it was found linear with correlation coeffi cient (r)=1.The method was validated for accuracy, limit of quantitation and robustness.
A simple, specifi c and accurate reverse phase high performance liquid chromatographic method was developed for the determination of cyclosporine in capsule dosage form.XTerra C18 column was used as stationary phase with mobile phase acetonitrile in combination with 0.1% trifl uoro acetic acid buffer and pH is adjusted to 1.4.Method was developed in an isocratic run of 20% trifl uoro acetic acid with 80% acetonitrile for 10 min, at fl ow rate of 1 ml/min.Effl uents were monitored at 210 nm.Retention time of cyclosporine was 3.855 min.The method was validated for specifi city, linearity, accuracy, precision, limit of quantifi cation, limit of detection, robustness and solution stability.Limit of quantifi cation and limit of detection of cyclosporine was found to be 100 ng/ml and 200 ng/ml.Recovery was found to be in the range of 98.08-101.55%.The proposed method was successfully applied for the quantitative determination of cyclosporine in a capsule dosage form.

Key words: Cyclosporine, immunosuppressant, RP-HPLC, Validation
Accuracy of the method was determined by calculating recovery of cyclosporine by method of standard addition.Known amount of cyclosporine (10, 15, 20 µg/ml) were added to prequantified sample solutions and the amount was estimated by measuring the peak area ratios by fitting these values to the straight line equation of calibration curve.
The intraday and interday precision study was carried out by estimating the responses 3 times on same day and 3 times on different days for 3 different concentrations (10, 15, 20 µg/ml) and the results are reported in terms of relative standard deviation (RSD) in Table 1.
Repeatability studies were carried out by estimating response of 3 different concentrations of cyclosporine (10, 15, 20 µg/ml) for 3 replicate determinations and results are reported in terms of relative standard deviation (RSD) in Table 1.
Specifi city of above described RP-HPLC method was determined by various parameters like retention time, resolution and tailing factor [9][10][11] .In the present study tailing factor of the peak was 1, with satisfactory resolution.Retention time and standard deviation (±SD) was found to be 3.58 minutes and ±0.53364 for six replicates.Thus, the peak obtained was sharp and have clear baseline.
A calibration curve was prepared using concentrations in the range of 0.100-0.200µg/ml.Standard deviation of y-intercepts of regression lines were determined and kept in the following equation for the determination of detection limit and quantitation limit.Detection limit=3.3σ/s, quantitation limit=10 σ/s, where σ is the standard deviation of y-intercepts of regression lines and s is the slope of the calibration curve.
Robustness of the method was studied by changing the composition of organic phase by ±5% and the pH by ±0.02%, and also by observing the stability of the drug for 24 h at 35° temperatures in mobile phase.
In order to check the stability, both the standard and sample solutions were analyzed over a period of 8 h at room temperature.The results for both the solutions remained almost unchanged and no significant degradation was observed within the indicated period.
Optimization of mobile phase was performed based on resolution, asymmetric factor and peak area obtained.Different mobile phase were tried but well resolved and good symmetrical peaks were obtained with mobile phase TFA and ACN (20:80, pH 1.4).Retention time of cyclosporine was found to be 3.855 min with satisfactory resolution.Overlain UV spectra of cyclosporine showed that drug absorbs appreciably 210 nm, so this wavelength was selected as the detection wavelength in liquid chromatography.Calibration curve for cyclosporine was obtained by plotting peak area versus concentration over the range of 5 µg/ml, and it was found to be linear with correlation coeffi cient (r)=1.
The detection limit and quantitation limit for cyclosporine was 0.100 µg/ml and 0.200 µg/ml, which suggest that nanogram quantity of it can be estimated accurately.The validation parameters are summarized in Table 1.The recovery of cyclosporine was found to be 99.38-101.11%.The proposed method was met for cyclosporine with the parameters of system suitability test as retention time 3.8 min with resolution 1.8 and tailing factor 1.
The present study described a new RP-HPLC method using simple mobile phase for the estimation of cyclosporine in oral dosage form.The method was validated and was found to be simple, sensitive, accurate and precise.Lactulose is a semi-synthetic disaccharide made from lactose by a chemical reaction which was first described in 1930 [1] .Lactulose is formed by the LA transformation of lactose via a 1, 2-enediol intermediate.Lactulose is much less stable in solution than lactose and may subsequently degrade via β-elimination to give galactose, tagatose and saccharinic acids and other low molecular weight products [2] .According to United States Pharmacopeia (2008) specifi cation lactulose syrup must not contain more than 16% galactose, 12% lactose, 8% epilactose and 1% fructose.Consequently a reliable method is needed to determine process related impurities in lactulose syrup.
Several methods for determination of lactulose in different samples are cited [3,4] in literature.However, when we tried to follow USP method we didn't achieve good resolution; it also used buffer in mobile phase and has longer retention time.Now it is the first time that we are going to report a method to quantify lactulose and process related sugar compounds in syrup formulation with a simple mobile phase composition and within a short time span.
Reference standard of lactulose was obtained from Platinum Pharma, Karachi, Pakistan.Acetonitrile HPLC grade (Fischer Scientifi c UK Limited, Bishop Meadow Road, Lough Borough, Leicestershire LE 11 5RG UK) and de-ionized water (filtered) were used to prepare the mobile phase.Standard

Fig. 2 :
Fig. 2: Percentage content in ten individual tablets of marketed formulation Diagrammatic representation of percentage content in ten individual tablet of units of marketed formulation (linear regression as per peak area rosiglitazone, USP limits for drug content is 85 -115%)