A Concise Study of Metal Impurities as Leachable and Extractable [Lead, Aluminium and Tin] in Eye Drop Formulation and Collapsible Tubes by ICP OES method

 

M. Gnana Raja¹, Dr. G. Geetha²

¹KMS Health Center, Chennai, India.

²PSG College of Pharmacy, Coimbatore, India.

 

ABSTRACT:

Metals such as Lead, Aluminium and Tin might some suppliers used in the synthesis of collapsible tube or some trace amount might instantly present in the raw materials of collapsible container. A selective ion determination method was developed by ICP OES for leachable and extractable of metal impurities. The method has been validated by using the parameters RF power of 1.2 KV, plasma flow of 15 L/min, Auxiliary gas flow of 1.5 L/min and plasma view at axial mode for all the metals. The wavelength was monitored for Lead, Aluminium and Tin at 220.353nm, 396.152 and 189.925 nm respectively. The method described is simple, sensitive, rugged, reliable and reproducible for the quantization of Lead, Aluminium and Tin in the leachate and extract from the drug product and container respectively.In this paper completely demonstrated the method of quantification of metal impurities Lead, Aluminium and Tin as a leachate and extract by ICP OES for varies solvents, stress condition and different extraction procedure for marketed eye drops availed in southern part of India. 

 

 

 

INTRODUCTION:

Leachable and Extractable is defined as per USFDA; leachables are a compound that leaches in to drug product formulation from the container or closure as a result direct contact with formulation. Extractables are compounds that can be extracted from the container closure system when in the presence of a solvent¹. The degree of the concern associated with the route of administration and packing concern. Usually high level leach may occur in inhalation, aerosols, transdermal ointment, and ophthalmic container.

 

 

 

 

 

 

Low level occurs in topical and oral solution and suspension. If the packing material is good it means it should not be toxic, genotoxic and impact drug efficacy. Harmful components that can originate from the packing manufacturing process it consists plasticizers, heavy metals and phthalates etc². An accurate leachable and extractable method shall be developed by controlled extraction study it deals about the extraction of the leachate from the container or closure by various extraction procedure like multiple solvents, vigorous and multiple extraction, optimize the extraction procedure and multiple analytical techniques. Analytical techniques usually employ GC-MS, GC-HS-MS, LC-MS, FT-IR, ICP-MS and ICP OES³.

 

The general analytical techniques employed for the inorganic metal impurities include titration, ion chromatography, capillary electrophoresis and inductively coupled plasma (ICP)⁴. Among the above said technique ICP is a versatile tool for detection and quantification of elements in accurate manner. The ICP technique is based on atomic spectrometry. Most specifically, the ICP-OES is emission spectrometric technique that exploits the fact that excited atoms emits energy at a given wavelength as the electron return to their ground state⁵. A given element emits energy at specific wavelength peculiar to its chemical character. The intensity of the energy emitted at that wavelength is proportional to the amount of that element in the analyzed sample. ICP-OES has additional advantages over the other techniques in terms of detection limits as well as speed of analysis. In ICP-OES sample experiences temperatures estimated to be in the vicinity of 10,000 K. This results in atomization and excitation of even most refractory elements with high efficiency so that detection limits for these elements with ICP-OES can be well over and order of magnitude better than the corresponding values of other techniques. The limit of quantitation values of most of the elements in ICP-OES in parts per million and even parts per billion. In number of analytical applications speed can be an important factor. Those advocating simultaneous ICP-OES regard it is the only method worth considering for this task because it is so much analyses sample in minutes is only fast enough if the sample preparation time takes only a few minutes. In other technique like ion chromatography, capillary electrophoresis stabilization is a time taking process and sensitivities are low when compared with ICP-OES⁶. The titration methods are not accurate especially while estimating the elements at lower concentrations and also errors could be expected⁷. Fifty seven elements were detected in bottled drinking water the influence of color and acidification⁸.

 

EXPERIMENTAL METHOD:

Instruments and Materials:

Agilent Inductively coupled Plasma system equipped with Optical Emission Spectrophotometer and system controlled through Agilent ICP Expert II software. The incubator used for the experiment is Max Q 4000 of Thermo Scientific.

 

Preparation of standard for Calibration Curve:

Calibration curve standard was prepared from 1mg/mL ICP OES standard of Lead, Aluminium and Tin in water and this was slightly acidified. Calibration standard was prepared from 0.01ppm to 5ppm. Data were shown in 2 to 4 for Lead, Aluminium and Tin respectively.

 

Preparation of Sample for Leachable:

5mL of sample was dissolved in 50mL of isopropylalcohol and evaporated to dryness. Added 1ml of nitric acid and added 9mL of water and analyzed by ICP OES. Data were shown in Table 10.

 

Method Validation:

The analytical method validation was carried out as per ICH method validation guidelines. The validation parameters addressed were Precision, Linearity, and Limit of quantization [LOQ] and Accuracy.

 

Precision:

5mL of sample was dissolved in 50mL of isopropylalcohol and evaporated to dryness. Added 1ml of nitric acid and added 9mL of water and analyzed by ICP OES. Six samples was prepared and analyzed, data were shown in Table 1.

 

LOD and LOQ Establishment:

LOQ was established by calibration curve method, ratio of standard deviation of the response and slope of calibration curve. For LOD and LOQ alpha value has taken for 3 and 10 respectively. Data were shown in Table 5.

 

Accuracy:

Accuracy was established LOQ to 5ppm of thee metals at three levels; it was spiked in sample at the respective concentration from LOQ, 50% and 100%. Data were shown in Table 6 to 8 for Lead, Aluminium and Tin respectively.

 

INSTRUMENT CONDITION:

Power	1.20 KW
plasma gas flow	15.0 (L/min)
Auxiliary gas flow	1.50 (L/min)
Torch type	Axial
Nebulizer type	Concentric glass nebulizer
Nebulizer pressure	0.75 (L/min)
Pump tube type	Peristantic
pump tube	solid white
pump rate	15 RPM
sample uptake rate	15 S

 

Preparation of Sample for Extractable:

Extraction method was optimized by varies extraction condition like solvents, buffer, forced degradation condition. Data were shown in Table 11.

 

RESULTS AND DISCUSSION:

ICP OES for the determination of metal impurities in collapsible container in marketed eye drops has been studied and validated some parameter as per ICH Guidelines. Metal impurities was determined as leachable from the eye drop formulation and extracted from the container by various stress and vigorous extraction conditions. Calibration curve made from 0.01 ppm to 5ppm for lead, aluminum and tin and correlation coefficient was found 0.9997, 0.9995 and 0.9992 respectively. Precision was performed for 1 ppm level for all three metals and percent RSD was found 6.0% to 12.7%. LOQ was determining by calibration curve method and LOQ was found to be 0.1ppm, 0.01ppm and 0.01 for Lead, Aluminium and Tin respectively. Accuracy was proved from 0.1ppm, 1ppm and 5ppm for all the three metals and overall recovery and percent RSD was found 91.8% to 110.3% and 2.1% to 7.6% respectively. Extractable was determined by various extracting condition by using various solvents. Isopropyl alcohol as extraction solvent was shown significant extraction efficiency. Above said all the parameter results tabulated in Table 1 to Table 11 and linearity curve was shown in Figure 1 to Figure 3.

 

 

 

 

 

Table 1: Precision

Sample	Lead		Aluminium		Tin
	C/S	ppm found	C/S	ppm found	C/S	ppm found
1	121	0.6	1254	0.6	55	0.8
2	112	0.5	1163	0.5	47	0.6
3	131	0.6	1312	0.6	51	0.7
4	128	0.6	1231	0.6	38	0.5
5	120	0.6	1421	0.6	54	0.7
6	115	0.5	1521	0.7	52	0.7
Average		0.6	Average	0.6	Average	0.7
SD		0.0	SD	0.1	SD	0.1
% RSD		6.0	% RSD	10.0	% RSD	12.7

 

Table 2: Linearity - Lead

Pb  220.353 Calibration (ppm)			Correlation Coeffieient: 0.999784
Lable	Flags	Int. (c/s)	Std Code	Cale Cone	Error	%Error
Blank		28.098	0.000	0.000	-	-
Standard11		48.883	0.010	0.010	0.000	3.9
Standard12		76.087	0.020	0.024	0.004	19.9
Standard13		141.812	0.050	0.057	0.007	13.7
Standard14		324.469	0.100	0148	0.048	48.1
Standard15		485.680	0.200	0229	0.029	14.4
Standard16		1224.35	0.500	0.598	0.098	19.6
Standard17		2122.38	1.000	1.047	0.047	4.7
Standard18		4018.92	2.000	1.9958	-0.005	-0.3
Standard19		9992.53	5.000	4.981	-0.019	-0.4

Curve Type: Liner                   Equation: y = 2000.6 x + 28.1

 

Table 3: Linearity - Aluminium

Al 396.152 Calibration (ppm)				Correlation Coefficient: 0.999505
Lable	Flags	Int. (c/s)	Std Code	Cale Cone	Error	%Error
Blank		121.816	0.000	0.000	-	-
Standard11		354.003	0.010	0.012	0.002	16.5
Standard12		559.042	0.020	0.022	0.002	9.7
Standard13		1289.59	0.050	0.059	0.009	17.2
Standard14		2712.94	0.100	0.130	0.030	30.0
Standard15		5120.51	0.200	0.251	0.051	25.4
Standard16		12011.7	0.500	0.597	0.051	19.3
Standard17		22021.1	1.000	1.099	0.097	9.9
Standard18		41682.3	2.000	2.086	0.099	4.3
Standard19		98425.0	5.000	4.933	0.086	-1.3

Curve Type: Liner                                   Equation: y = 19925.7 x + 121.8

 

Table 4: Linearity - Tin

Sn 189.925 Calibration (ppm)				Correlation Coefficient: 0.999203
Lable	Flags	Int. (c/s)	Std Code	Cale Cone	Error	%Error
Blank		20.522	0.000	0.000	-	-
Standard1		28.846	0.010	0.012	0.002	20.0
Standard2		33.148	0.020	0.018	-0.002	-9.0
Standard3		53.129	0.050	0.047	-0.003	-6.0
Standard4		85.547	0.100	0.094	-0.006	-6.2
Standard5		161.254	0.500	0.203	0.003	1.5
Standard6		423.626	1.0010	0.581	0.081	16.2
Standard7		751.238	2.000	1.054	0.054	5.4
Standard8		1516.50	5.000	2.157	0.157	7.8
Standard9		3431.71	5.000	4.918	-0.082	-1.6

Curve Type: Liner                                   Equation: y: = 693.6 x + 20.5

 

Table 5: LOQ

Solvents	SD	Slope	PPM
Lead	21	1982	0.1
Aluminium	19	19645	0.01
Tin	1	687	0.01

 

 

 

Table 6: Accuracy - Lead

S.No	Level	C/S	ppm spiked	ppm recovered	% Recovery	Average	% RSD
1	0.1ppm	221	0.1	0.11	105.5	102.8	5.4
		210		0.10	100.3
		198		0.09	94.6
		210		0.10	100.3
		221		0.11	105.5
		231		0.11	110.3
2	1ppm	1956	1	0.93	93.4	98.8	6.4
		2215		1.06	105.8
		2036		0.97	97.2
3	5ppm	11214	5	5.36	107.1	100.8	6.3
		10541		5.03	100.7
		9894		4.72	94.5
		11054		5.28	105.6
		10245		4.89	97.9
		10987		5.25	104.9

 

Table 7: Accuracy - Aluminium

S.No	Level	C/S	ppm spiked	ppm recovered	% Recovery	Average	% RSD
1	0.01ppm	210	0.01	0.01	95.9	98.0	4.6
2		224		0.01	102.3
3		228		0.01	104.1
4		214		0.01	97.7
5		211		0.01	96.3
6		201		0.01	91.8
1	1ppm	20141	1	0.92	92.0	98.6	7.6
2		21254		0.97	97.1
3		23387		1.07	106.8
1	5ppm	113254	5	5.17	103.4	99.2	6.6
2		102547		4.68	93.7
3		98541		4.50	90.0
4		115478		5.27	105.5
5		115478		5.27	105.5
6		106547		4.87	97.3

 

Table 8: Accuracy - Tin

S.No	Level	C/S	ppm spiked	ppm recovered	% Recovery	Average	% RSD
1	0.01ppm	7	0.01	0.01	95.8	100.3	7.0
2		7		0.01	95.8
3		8		0.01	109.4
4		8		0.01	109.4
5		7		0.01	95.8
6		7		0.01	95.8
1	1ppm	721	1	0.99	98.6	100.9	2.1
2		741		1.01	101.4
3		751		1.03	102.7
1	5ppm	3512	5	4.80	96.1	99.8	2.7
2		3621		4.95	99.1
3		3754		5.14	102.7
4		3562		4.87	97.5
5		3687		5.04	100.9
6		3741		5.12	102.4

 

 

Table 9: Overall compilation of validation [Results of entire study]

Parameter	Acceptance criteria	Results
Precision	% RSD (six sample preparation) Not More Than 15.0%	6% to 12.7%
Linearity	Correlation coefficient Not Less Than 0.999	0.9992 to 0.9997
Accuracy	Percent Recovery 85.0% to 115.0%	98.0% to 120.8%

 

 

Table 10: Leachable

Parameter	‘ppm’ found
Lead	0.1
Aluminium	0.7
Tin	0.6

 

 

 

 

 

 

 

Table 11: Extractable

S.No	Solvent	Condition	“ppm” Found
	Water	Metals	Lead	Aluminium	Tin
1		sonication for 30 Minutes	0.3	0.2	0.1
2		Reflux 50°C for 30 Minutes	0.5	0.2	0.1
3		auto clave for 1 hour at 110°C	0.6	0.5	0.3
4		Soxhelt for 1 hour	0.5	0.5	0.4
5		37°C for 72 hours	0.3	0.2	0.1
6		50°C for 72 hours	0.3	0.2	0.2
7		70°C for 24 hours	0.4	0.3	0.4
8		121°C for 1 hour	0.6	0.6	0.6
9	0.1 N HCl	sonication for 30 Minutes	0.5	0.3	0.2
10		Reflux 50°C for 30 Minutes	0.2	0.3	0.1
11		auto clave for 1 hour at 110°C	0.6	0.5	0.6
12		Soxhelt for 1 hour	0.5	0.5	0.4
13		37°C for 72 hours	0.1	0.2	0.3
14		50°C for 72 hours	0.6	0.4	0.6
15		70°C for 24 hours	0.5	0.4	0.5
16		121°C for 1 hour	0.6	0.5	0.6
17	pH 4.5 acetate buffer	sonication for 30 Minutes	0.3	0.2	0.1
18		Reflux 50°C for 30 Minutes	0.4	0.3	0.2
19		auto clave for 1 hour at 110°C	0.5	0.6	0.1
20		Soxhelt for 1 hour	0.2	0.6	0.4
21		37°C for 72 hours	0.5	0.6	0.3
22		50°C for 72 hours	0.4	0.5	0.4
23		70°C for 24 hours	0.1	0.3	0.3
24		121°C for 1 hour	0.7	0.6	0.8
25	pH 6.8 phosphate buffer	sonication for 30 Minutes	0.2	0.3	0.5
26		Reflux 50°C for 30 Minutes	0.3	0.4	0.4
27		auto clave for 1 hour at 110°C	0.2	0.2	0.1
28		Soxhelt for 1 hour	0.3	0.5	0.6
29		37°C for 72 hours	0.6	0.5	0.5
30		50°C for 72 hours	0.5	0.6	0.7
31		70°C for 24 hours	0.4	0.6	0.7
32		121°C for 1 hour	0.7	0.6	0.6
33	50% Alcohol	sonication for 30 Minutes	0.8	0.8	0.9
34		Reflux 50°C for 30 Minutes	0.8	0.8	0.9
35		auto clave for 1 hour at 110°C	0.7	0.8	0.9
36		Soxhelt for 1 hour	1.1	1.3	1.4
37		37°C for 72 hours	1.2	1.1	1.2
38		50°C for 72 hours	0.8	0.7	0.8
39		70°C for 24 hours	0.7	0.8	0.7
40		121°C for 1 hour	1.3	1.3	1.4
41	Heptane	sonication for 30 Minutes	1.1	1.2	1.1
42		Reflux 50°C for 30 Minutes	0.9	1.3	1.4
43		auto clave for 1 hour at 110°C	1.4	1.3	1.4
44		Soxhelt for 1 hour	1.5	1.6	1.2
45		37°C for 72 hours	0.8	0.9	1.1
46		50°C for 72 hours	0.8	0.9	1.0
47		70°C for 24 hours	0.9	1.1	1.1
48		121°C for 1 hour	1.6	1.5	1.7
49	Isopropylalcohol	sonication for 30 Minutes	1.3	1.3	1.4
50		Reflux 50°C for 30 Minutes	1.8	1.9	2.1
51		auto clave for 1 hour at 110°C	1.9	1.8	1.8
52		Soxhelt for 1 hour	2.3	2.1	2.2
53		37°C for 72 hours	1.6	1.6	1.5
54		50°C for 72 hours	1.7	1.7	1.8
55		70°C for 24 hours	2.1	2.2	2.3
56		121°C for 1 hour	5.4	7.1	6.2

 

 

Figure 1: Calibration Curve for Aluminium

 

Figure 2: Calibration Curve for Lead

 

 

Figure 3: Calibration Curve for Tin

 

 

CONCLUSION:

This study presents a simple and validated ICP OES method for estimation of metal impurities as leachable and extractable of eye drop formulations and collapsible container which was available in marketed. The method developed is specific, accurate, precise and linear. The content of metal impurities present in the marketed eye drop formulations was found below 1ppm.

 

REFERENCES:

1.     David B. Lewis, Ph.D. Office of New Drug Quality Assessment Current FDA Perspective on Leachable Impurities in Parenterals and Ophthalmic Drug products. www.fda.gov.

2.     Douglas J.Ball et.al Leachable and Extractable Hand book, safety Evaluations, Qualifications and Best practice Applied to inhalation drug products.

3.     Kelth Scott has studied Extractables and Leachables testing of polymer device components, processing pharmaceutical polymer, 20-21 June-Basel, Switzerland.

4.     C.B. Boss, K.J Fredeen Concept, Instrumentation and Techniques in Inductively Coupled Plasma Optical Emission Spectrometry, 2^nd edition Perkin-Elmer, Norwalk, CT, 1977.

5.     S. Greenfiels, I.L Jones, C.T. Berry, ‘High pressure Plasma as spectroscopic Emission Sources’, analyst 89(1), 713-720 (1964).

6.     The guide to Technique and Applications for Atomic Spectroscopy, Perkin-Elmer, CT, 1990.

7.     Venkata Vivekanand Vallapragada et.al has studied A validated inductively coupled plasma optical emission spectrometry method to estimate free calcium and phosphorus in Invitro phosphate binding study of Eliphos Tablets 2011; 2, 718-725.

8.     Clemens Riemann et.al. has studied Bottled drinking water: water contamination from bottle materials (glass, hard PET, soft PET), the influence of color and acidification.

 

 

 

Accepted on 24.06.2018           © RJPT All right reserved

Research J. Pharm. and Tech 2018; 11(10): 4415-4420.