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Cleaning validation in the toiletries industry
Analytica Chimica Acta 467 (2002) 261–266
Cleaning validation in the toiletries industry Nikos E. Mazonakis, Panagiota H. Karathanassi, Dimitrios P. Panagiotopoulos, Paraskevi G. Hamosfakidi, Dimitrios A. Melissos∗ FAMAR S.A., BU Toiletries, QC Laboratory, QA Department, 48th km NEO Athens-Lamia, Avlonas 19011, Greece Received 9 November 2001; received in revised form 10 April 2002; accepted 17 May 2002
Abstract Demonstration with a suitable quantitative analytical technique (liquid chromatography, LC), that application of routine cleaning procedures to toiletries production equipment (preparation and storage tanks, filling nozzles and utensils) assures the absence of the previously manufactured product. A quality assurance approach is described, from preparation of a suitable protocol of actions, to the qualification of analytical results at detection and quantitation limits. The analytical method used showed satisfactory sensitivity for the determination of residues of the selected “worst case” (a sunscreen product containing ethylhexyl (octyl) methoxycinnamate, OMC). © 2002 Elsevier Science B.V. All rights reserved. Keywords: Cleaning validation; Liquid chromatography; Sunscreen cosmetic products; UV filters; Ethylhexyl (octyl) methoxycinnamate (OMC)
1. Introduction The appearance of the issue of cleaning validation in pharmaceuticals has taken place the last 5–7 years and it has turned into a complicated case study. Terminology like “pharmacological potency” and “lowest effect limit” played a very important role for evaluation of cleaning practices among pharmaceutical companies [1–5]. The scope was to fulfil legislative demands for effective cleaning procedures [6,7] and to take actions for reducing the scale-up factor due to incomplete cleaning of multipurpose manufacturing equipment. FAMAR S.A., as a contract manufacturer in pharmaceuticals, had to comply with this new challenging era. In the cosmetics and toiletries industry, the implementation of such theories is under investigation and all relevant cleaning and sanitization legislation
is in draft [8]. The aim of the present work was to evaluate the pharmaceutical approach in the toiletries industry with the appropriate definition of the critical parameters that have been taken into consideration. The specific absorbance of widely used sunscreen filters [9] and legislative limits for maximum permitted concentrations of additives in toiletry products [10] determined the frame of our study. Although in pharmaceutical analysis there are various methods combining cleaning validation with liquid chromatographic (LC) analysis [11], for suncare cosmetic products similar publications do not exist. We have used a validated LC method [12–15] for detection of UV filter residues in equipment for manufacturing common sunscreen products.
2. Experimental ∗
Corresponding author. Tel.: +30-10-8047729; fax: +30-10-8047729. E-mail address: [email protected] (D.A. Melissos).
Before any experimental work, one has to design in a protocol all the steps that must be followed in
0003-2670/02/$ – see front matter © 2002 Elsevier Science B.V. All rights reserved. PII: S 0 0 0 3 - 2 6 7 0 ( 0 2 ) 0 0 4 8 6 - 5
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order to achieve reliable results. In a cleaning validation protocol (CVP) these steps are the following. 2.1. Definition of ingredients under assessment The ingredients under assessment are active raw materials, which cannot easily be removed after production (manufacture and filling processes) and can accumulate in the next products. In parallel, for the same ingredients there are legislative limits, as far as it concerns the maximum concentration used in the products. Sunscreen filters represent those ingredients in this study. 2.2. Setting the variables 2.2.1. Type and surface area of the tanks and utensils with which the product will be in contact For the purpose of this study we focused on a 6 t manufacturing vessel equipped with stirrer, scraper and homogenizer. The total contact surface is calculated or retrieved from the technical study of the equipment. In this case, the vessel’s surface area is 18.4 m2 . As expected, there are always some small parts of the surface (i.e. corners, or surfaces opposite to the spray of the cleaning machine), for which the cleaning procedure is probably not efficient. These surfaces are defined, characterized and mapped as “difficult to clean” (Section 2.5).
2.2.2. Grouping of products per equipment In the 6 t vessel, sunscreen products, shampoos and foam baths, creams and lotions can be manufactured. For each group one product was studied as the worst case for validation (Section 2.2.5). As a representative example we will focus on the sunscreen product group, which contain UV filters as active ingredients. 2.2.3. Physicochemical characteristics of ingredients to be assessed The concentration (%, w/w) of sunscreen filters in the product is tabulated as well as their relevant potency in terms of specific absorbance (A) of the ingredient (Table 1). Especially for UV filters, potency is also defined as absorption in the region of UVA (I&II) or UVB, where UVAI is 340–400 nm, UVAII 320–340 nm and UVB 290–320 nm. UVB irradiation is considered to be more dangerous and carcinogenic as it can penetrate to the lower epidermis layer [9]. Information given concerning maximum legislative limits that apply mainly to dermatological and toxic effects, and are always taken into consideration for formulation, is also tabulated as an indirect index for the study of the ingredient. The meaning of this information is that a high specific absorbance of an ingredient (filter) in the UVB range (290–320 nm), with a concentration in the product close to the legislative limit, is certainly suitable for a case study (potent ingredient). Finally, solubility in water and high viscosity
Table 1 Summary data used for the selection of the “worst case” product to be validated, in a 6000 kg (maximum batch size) manufacturing vessela Ingredient datab,c
HS
B-3
OMC
BMDM
OS
λmax (nm 1%, EtOH, 1 cm) A @ λmax (absorbance, 1%, EtOH, 1 cm) Legislation max. permitted (%, w/w)
306 175 10
287 650 10
310 850 10
357 1140 5
305 175 5
Product group of sunscreens
UV filters in formulation (%, w/w)
(1) (2) (3) (4) (5) (6)
4.0
Sun lotion SPF2 Sun lotion SPF8 Kids sun lotion SPF15 Sun lotion SPF30 Kids sun lotion SPF30 Kids sun lotion SPF50 a
5.0 8.0 8.0
2.0 3.0 4.0 3.0 6.0
7.0 7.5 7.5 7.5 7.5
3.0 2.0
5.0 5.0 2.5
Minimum batch size of 3000 kg. HS: homomenthyl salicylate; B-3: oxybenzone; OMC: ethylhexyl (octyl) methoxycinnamate; BMDM: butylmethoxydibenzoyl methane; OS: ethylhexyl (octyl) salicylate. c Absorbance data have been retrieved from relevant material specifications and verified in-house. b
N.E. Mazonakis et al. / Analytica Chimica Acta 467 (2002) 261–266
(ca. 45,000 cps for our case study), play an important role, as this kind of material has to be washed out only with water, without any organic solvent. 2.2.4. Batch size It is important for each group of products to document the minimum and maximum batch size (Table 1). 2.2.5. Worst case scenario A manufacturing tank, containing a product with a very potent ingredient, is under a routine cleaning procedure (Section 2.4). The tank is loaded with the maximum batch size. The product is relatively insoluble and tends to remain on difficult to clean surfaces of the tank. The next production has the minimum batch size for that specific tank. This scenario obviously leads to accumulation of potent ingredients in the next batch. The choice of the reference product for study, which will be the worst case for cleaning validation, will be made taking into consideration: (i) the maximum specific absorbance (A) of ingredients at a high percentage concentration in a product and within the most dangerous irradiation range (UVB), (ii) the solubility, (iii) the legislative limits of the ingredients, (iv) the surface of the vessel and (v) the batch size. The reference product for study may contain several potent ingredients from which the worst one has to be selected (Section 2.3.3) using the above criteria. 2.3. Setting the limits Tentative acceptance limits. 2.3.1. Pharmaceutical approach [1–5] Permissible residue <0.1% (3-log reduction) of the lowest ingredient concentration in the formulated product of the group in the given equipment. All factors that take part in the worst case scenario (Section 2.2.5) form equations that define the maximum concentration required to be determined in order that the equipment can be considered as “clean” (Section 2.6): ACDF Residue per swab (g per swab) = 100E Residue in mg l−1 (ppm) of solvent rinse=
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where A is the lowest ingredient concentration (mg g−1 ), C the minimum batch size of the group (g), D the sampling surface (default, 10−2 m2 ), E the manufacturing vessel surface (m2 ), F the recovery factor. Protocols usually define a minimum accepted of 50%, and G the solvent rinse volume (l) 2.3.2. References trend In case the above equations result in high concentrations, then the maximum permissible residue is 10 mg l−1 (ppm). 2.3.3. Definition of the product and the ingredient for study From the data presented in Table 1, we have selected the product kids sun lotion SPF50 (product #6) and the ingredient ethylhexyl (octyl) methoxycinnamate (OMC) as the “worst case”. All other ingredients were excluded following the guidelines of the relevant Section 2.2.5. 2.3.3.1. Calculation of limits. Concentration, A 1 mg g−1 (0.10 % w/w in Table 1) Minimum batch size, C 3 × 106 g Sampling surface, D 10−2 m2 Recovery factor, F 87.6% (worst experimental case, see Section 2.7.3 and Table 3) Vessel surface, E 18.4 m2 Solvent rinse volume, G 20 l Result from Eq. (1) 1428 g per swab Result from Eq. (2) 131 mg l−1 (ppm) Final limit 10 mg l−1 (ppm) or g per swab This limit was calculated for the specific case only. In other equipment, with a different group of products, the results could differ. 2.4. Routine cleaning procedure
(1) ACF 100, 000G (2)
Washing of the manufacturing vessels is performed by means of a high pressure cleaning machine. The routine procedure is the following: The vessel is washed with deionized water and a suitable detergent, at a minimum of 85 ◦ C. The vessel
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is finally rinsed with hot (minimum 85 ◦ C) deionized (purified) water. Times for both cleaning procedures in this study have been set at 45 and 5 min, using two criteria: optically clean surfaces and no UV absorbance (200–400 nm) for a sample of the final rinse with purified water. 2.5. Sampling (for CVP purposes only) The whole CVP can be useful only if sampling has been designed and performed properly. The scope is to produce reliable results, chemical and microbiological. Samples are taken from the following: • Final rinse (purified water) of the equipment, at the end of the routine cleaning procedure, for full chemical (according to European Pharmacopoeia) and microbiological tests. • Surface of the equipment using swabs, after the final rinse, for microbiological test. • Solvent rinse (additional cleaning with water or organic solvent, i.e. ethanol, where ingredients to be determined can be dissolved) for determination of ingredients under investigation. The volume of the solvent must be relevant to the size of the equipment. • “Difficult to clean” surfaces, particularly on equipment not accessible to solvent rinse such as stirring axis, scraper, inner vessel surface (Table 2), using swabs after solvent rinse, for determination of ingredients under investigation. All samples should be
analyzed within 24 h, in order to avoid degradation products from the determinants. 2.6. Specifications after cleaning procedures • Visual cleanliness after final rinse (routine). • No microbiological contamination of final rinse and swabs (CVP). • No significant UV absorbance of final rinse (tentative maximum is the absorbance of 10 ppm solution of the ingredient under investigation, CVP). • Solvent rinse and surface swabs concentration must be better than the acceptance limits (Section 2.3.3, CVP). 2.7. Method 2.7.1. Instruments A UV–VIS spectrophotometer (Perkin-Elmer L2) was used for the assessment of the final rinse using quartz cuvettes having a 1 cm optical path. (Sections 2.4 and 2.6). A Varian Star LC system was used (UV detector 9050 and pump 9012) equipped with an autosampler (9100) with a 20 l loop and a C18 reversed phase column (Kromasil® 250 mm × 4.5 mm, 5 m packing material) in line with a similar pre-column (30 mm × 4.6 mm) for assessment of solvent rinse and swabs. The mobile phase consist of isocratic elution of a MeOH:H2 O solution (90:10, v/v) at a flow rate of 1.2 ml min−1 at ambient temperature. The detector was set at 305 nm.
Table 2 Analytical data and validation results for OMC as retrieved from liquid chromatographic analysis Batch number (kids lotion SPF 50)
Stirring axis (g per swab)
Scraper (g per swab)
Inner vessel surface (g per swab)
Solvent (EtOH) rinse (mg l−1 )
0105A 0111B 0112C 0112D 0112E 0201F 0201G 0202H
6.60 5.85 5.92 7.45 4.86 Nqa 4.21 5.12
6.90 7.11 3.59 6.27 5.77 6.88 6.12 5.44
8.42 6.36 4.38 7.77 Nq 9.32 Nq 5.43
7.25 6.26 Nq 4.69 Nq 7.00 Nq 3.81
Results after cleaning for OMC residual content after production of product #6. a Nq: non-quantifiable values (<3.34 mg l−1 ).
N.E. Mazonakis et al. / Analytica Chimica Acta 467 (2002) 261–266
2.7.2. Analysis of rinse and swabs by liquid chromatography The method that was used for the determination of sunscreen filters content (similar to those referred to in the literature) [12–15] was the same with the one used for routine analysis. This is an in-house method that was developed, validated and approved for FAMAR’s customers (multinational companies). Routine assay concentration of the ingredient OMC is 150 mg l−1 (ppm). The concentration of OMC in the product was 7.5% (w/w). Validation for linearity and precision at concentrations of 0.5, 1, 10, 50, 100, 150 mg l−1 (n = 6) was carried out and the determination of detection (DL) and quantitation limits (QL) were evaluated (Table 2). 2.7.2.1. Standard preparation. A working reference standard, from approved raw material (OMC, BASF,
265
Germany) was used for all weightings. Approximately 100 mg of OMC was accurately weighed into a 100 ml volumetric flask and was dissolved in and diluted to volume with isopropanol. In order to make calibration measurements, the relevant volumes were pipetted from this solution into 100 ml volumetric flasks, mixed and diluted to volume with isopropanol. 2.7.2.2. Sample preparation. The solvent rinse is injected directly and swabs are given a 2 ml solvent rinse before injection. All tests have been performed in triplicate. 2.7.3. Recovery Recovery in this study means how well the residue can be retrieved from the equipment. Simulation of swab sampling was performed by placing solutions
Fig. 1. Liquid chromatograms of: (A) routine sample preparation for the determination of OMC in kids lotion SPF 50, batch 0112D, at attenuation 1024 and (B) solvent rinse residue after cleaning of the vessel, at attenuation 32. Chromatographic conditions are described in Section 2.
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4. Conclusions
Table 3 Recovery of OMC Cnominal (mg l−1 )
Ccalculated (mg l−1 )
1.00 10.00 50.00 100.0 150.0
0.88 9.15 47.70 101.35 150.50
± ± ± ± ±
0.003 0.02 0.22 0.26 0.23
Recovery (%) 87.6 91.5 95.4 101.3 100.3
± ± ± ± ±
0.3 0.2 0.4 0.3 0.2
of the ingredient under investigation on a stainless steel plate with dimensions equal to those of sampling (10 cm×10 cm = 10−2 m2 ), drying and recovery with the swab wetted with the solvent rinse. Range of tests: 1.00–150.0 mg l−1 . All tests have been performed in triplicate and the averages are shown in Table 3.
The results of samples after the routine cleaning procedure are well within limits with the assurance of the validated method used. The tentative limit of 10 mg l−1 can be considered as the final maximum acceptance limit. As all validation protocols after three consecutive determinations, a yearly monitoring can be conducted. Any deviations must be investigated through the correct use of washing and/or analytical procedures, as well as the nature of the next product (i.e. potential risks from accumulation of active ingredients). The approach of the 3-log reduction of residues can be proved to be valuable when the method used is not very sensitive.
3. Results and discussion References Analytical results obtained from the validation of the method (Table 2) and recovery (Table 3) showed that all assumptions and calculations made in the CVP proved that residues can be detected within the expected limits (rinse and swab concentration < 10 mg l−1 or g per swab, respectively). The analytical method used for determination of the residues is able to detect OMC down to 1.11 mg l−1 and to quantify >3.34 mg l−1 (Fig. 1). Linearity in the range 0.50–150 mg l−1 , A = 39,999 (±189) × C − 7971 (±13378), R = 0.99994 and precision at all calibration points, R.S.D. = 0.21–1.35% (<2.0%) assures that all values within this range are reliable. It must be clear that: only one sample is valid each time for the solvent rinse and each swab sample (out of three replicates) must be from different points. Standard deviation for these replicates is not applicable. As far as it concerns recovery, it is demonstrated that residues detectable by the analytical method within the range 1–150 mg l−1 can also be recovered by the selected method of sampling. The recovery range of 87.6–101.3% shows the good accuracy of the method. Considering the random errors of sampling at low concentrations, the recovery is very high and well accepted from the protocol (Section 2.3.1).
[1] R.C. Hwang, D.L. Kowalski, J.E. Truelove, Pharm. Technol. 21 (1) (1997) 21. [2] K.M. Jenkins, A.J. Vanderwielen, Pharm. Technol. 18 (4) (1994) 60. [3] G.L. Fourman, M.V. Mullen, Pharm. Technol. 17 (4) (1993) 54. [4] J. Agalloco, J. Parenter. Sci. Technol. 46 (5) (1992) 163. [5] J.A. Shea, W.F. Shamrock, C.A. Abboud, R.W. Woodeshick, L.Q. Nguyen, J.T. Rubino, J. Segretario, Pharm. Dev. Technol. 1 (1) (1996) 69. [6] Guide to Inspections of Validation of Cleaning Processes, FDA, July 1993. [7] EU Guide to Good Manufacturing Practice, Eudralex, Vol. 4, Annex 15, 2001. [8] Cleaning and Sanitization, CTFA, Public Review Draft, 16 April 2001. [9] H.V. DeBuys, S.B. Levy, J.C. Murray, D.L. Madey, S.R. Pinnell, Dermatol. Clin. 18 (4) (2000) 577. [10] EEC Directive 768/1976, Annexes VI and VII. [11] R. Raghavan, M. Burchett, D. Loffredo, J.A. Mulligan, Drug Dev. Ind. Pharm. 26 (4) (2000) 429. [12] A. Chisvert, M.C. Pascual-Marti, A. Salvador, J. Chromatogr. A 921 (2) (2001) 207. [13] M. Cambon, N. Issachar, D. Castelli, C.J. Robert, Cosmet. Sci. 52 (1) (2001) 1. [14] A. Chisvert, M.C. Pascual-Marti, A. Salvador, Fresenius J. Anal. Chem. 369 (7/8) (2001) 638. [15] G. Potard, C. Laugel, A. Baillet, H. Schaefer, J.P. Marty, Int. J. Pharm. 189 (2) (1999) 249.
Cleaning validation in the toiletries industry Nikos E. Mazonakis, Panagiota H. Karathanassi, Dimitrios P. Panagiotopoulos, Paraskevi G. Hamosfakidi, Dimitrios A. Melissos∗ FAMAR S.A., BU Toiletries, QC Laboratory, QA Department, 48th km NEO Athens-Lamia, Avlonas 19011, Greece Received 9 November 2001; received in revised form 10 April 2002; accepted 17 May 2002
Abstract Demonstration with a suitable quantitative analytical technique (liquid chromatography, LC), that application of routine cleaning procedures to toiletries production equipment (preparation and storage tanks, filling nozzles and utensils) assures the absence of the previously manufactured product. A quality assurance approach is described, from preparation of a suitable protocol of actions, to the qualification of analytical results at detection and quantitation limits. The analytical method used showed satisfactory sensitivity for the determination of residues of the selected “worst case” (a sunscreen product containing ethylhexyl (octyl) methoxycinnamate, OMC). © 2002 Elsevier Science B.V. All rights reserved. Keywords: Cleaning validation; Liquid chromatography; Sunscreen cosmetic products; UV filters; Ethylhexyl (octyl) methoxycinnamate (OMC)
1. Introduction The appearance of the issue of cleaning validation in pharmaceuticals has taken place the last 5–7 years and it has turned into a complicated case study. Terminology like “pharmacological potency” and “lowest effect limit” played a very important role for evaluation of cleaning practices among pharmaceutical companies [1–5]. The scope was to fulfil legislative demands for effective cleaning procedures [6,7] and to take actions for reducing the scale-up factor due to incomplete cleaning of multipurpose manufacturing equipment. FAMAR S.A., as a contract manufacturer in pharmaceuticals, had to comply with this new challenging era. In the cosmetics and toiletries industry, the implementation of such theories is under investigation and all relevant cleaning and sanitization legislation
is in draft [8]. The aim of the present work was to evaluate the pharmaceutical approach in the toiletries industry with the appropriate definition of the critical parameters that have been taken into consideration. The specific absorbance of widely used sunscreen filters [9] and legislative limits for maximum permitted concentrations of additives in toiletry products [10] determined the frame of our study. Although in pharmaceutical analysis there are various methods combining cleaning validation with liquid chromatographic (LC) analysis [11], for suncare cosmetic products similar publications do not exist. We have used a validated LC method [12–15] for detection of UV filter residues in equipment for manufacturing common sunscreen products.
2. Experimental ∗
Corresponding author. Tel.: +30-10-8047729; fax: +30-10-8047729. E-mail address: [email protected] (D.A. Melissos).
Before any experimental work, one has to design in a protocol all the steps that must be followed in
0003-2670/02/$ – see front matter © 2002 Elsevier Science B.V. All rights reserved. PII: S 0 0 0 3 - 2 6 7 0 ( 0 2 ) 0 0 4 8 6 - 5
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order to achieve reliable results. In a cleaning validation protocol (CVP) these steps are the following. 2.1. Definition of ingredients under assessment The ingredients under assessment are active raw materials, which cannot easily be removed after production (manufacture and filling processes) and can accumulate in the next products. In parallel, for the same ingredients there are legislative limits, as far as it concerns the maximum concentration used in the products. Sunscreen filters represent those ingredients in this study. 2.2. Setting the variables 2.2.1. Type and surface area of the tanks and utensils with which the product will be in contact For the purpose of this study we focused on a 6 t manufacturing vessel equipped with stirrer, scraper and homogenizer. The total contact surface is calculated or retrieved from the technical study of the equipment. In this case, the vessel’s surface area is 18.4 m2 . As expected, there are always some small parts of the surface (i.e. corners, or surfaces opposite to the spray of the cleaning machine), for which the cleaning procedure is probably not efficient. These surfaces are defined, characterized and mapped as “difficult to clean” (Section 2.5).
2.2.2. Grouping of products per equipment In the 6 t vessel, sunscreen products, shampoos and foam baths, creams and lotions can be manufactured. For each group one product was studied as the worst case for validation (Section 2.2.5). As a representative example we will focus on the sunscreen product group, which contain UV filters as active ingredients. 2.2.3. Physicochemical characteristics of ingredients to be assessed The concentration (%, w/w) of sunscreen filters in the product is tabulated as well as their relevant potency in terms of specific absorbance (A) of the ingredient (Table 1). Especially for UV filters, potency is also defined as absorption in the region of UVA (I&II) or UVB, where UVAI is 340–400 nm, UVAII 320–340 nm and UVB 290–320 nm. UVB irradiation is considered to be more dangerous and carcinogenic as it can penetrate to the lower epidermis layer [9]. Information given concerning maximum legislative limits that apply mainly to dermatological and toxic effects, and are always taken into consideration for formulation, is also tabulated as an indirect index for the study of the ingredient. The meaning of this information is that a high specific absorbance of an ingredient (filter) in the UVB range (290–320 nm), with a concentration in the product close to the legislative limit, is certainly suitable for a case study (potent ingredient). Finally, solubility in water and high viscosity
Table 1 Summary data used for the selection of the “worst case” product to be validated, in a 6000 kg (maximum batch size) manufacturing vessela Ingredient datab,c
HS
B-3
OMC
BMDM
OS
λmax (nm 1%, EtOH, 1 cm) A @ λmax (absorbance, 1%, EtOH, 1 cm) Legislation max. permitted (%, w/w)
306 175 10
287 650 10
310 850 10
357 1140 5
305 175 5
Product group of sunscreens
UV filters in formulation (%, w/w)
(1) (2) (3) (4) (5) (6)
4.0
Sun lotion SPF2 Sun lotion SPF8 Kids sun lotion SPF15 Sun lotion SPF30 Kids sun lotion SPF30 Kids sun lotion SPF50 a
5.0 8.0 8.0
2.0 3.0 4.0 3.0 6.0
7.0 7.5 7.5 7.5 7.5
3.0 2.0
5.0 5.0 2.5
Minimum batch size of 3000 kg. HS: homomenthyl salicylate; B-3: oxybenzone; OMC: ethylhexyl (octyl) methoxycinnamate; BMDM: butylmethoxydibenzoyl methane; OS: ethylhexyl (octyl) salicylate. c Absorbance data have been retrieved from relevant material specifications and verified in-house. b
N.E. Mazonakis et al. / Analytica Chimica Acta 467 (2002) 261–266
(ca. 45,000 cps for our case study), play an important role, as this kind of material has to be washed out only with water, without any organic solvent. 2.2.4. Batch size It is important for each group of products to document the minimum and maximum batch size (Table 1). 2.2.5. Worst case scenario A manufacturing tank, containing a product with a very potent ingredient, is under a routine cleaning procedure (Section 2.4). The tank is loaded with the maximum batch size. The product is relatively insoluble and tends to remain on difficult to clean surfaces of the tank. The next production has the minimum batch size for that specific tank. This scenario obviously leads to accumulation of potent ingredients in the next batch. The choice of the reference product for study, which will be the worst case for cleaning validation, will be made taking into consideration: (i) the maximum specific absorbance (A) of ingredients at a high percentage concentration in a product and within the most dangerous irradiation range (UVB), (ii) the solubility, (iii) the legislative limits of the ingredients, (iv) the surface of the vessel and (v) the batch size. The reference product for study may contain several potent ingredients from which the worst one has to be selected (Section 2.3.3) using the above criteria. 2.3. Setting the limits Tentative acceptance limits. 2.3.1. Pharmaceutical approach [1–5] Permissible residue <0.1% (3-log reduction) of the lowest ingredient concentration in the formulated product of the group in the given equipment. All factors that take part in the worst case scenario (Section 2.2.5) form equations that define the maximum concentration required to be determined in order that the equipment can be considered as “clean” (Section 2.6): ACDF Residue per swab (g per swab) = 100E Residue in mg l−1 (ppm) of solvent rinse=
263
where A is the lowest ingredient concentration (mg g−1 ), C the minimum batch size of the group (g), D the sampling surface (default, 10−2 m2 ), E the manufacturing vessel surface (m2 ), F the recovery factor. Protocols usually define a minimum accepted of 50%, and G the solvent rinse volume (l) 2.3.2. References trend In case the above equations result in high concentrations, then the maximum permissible residue is 10 mg l−1 (ppm). 2.3.3. Definition of the product and the ingredient for study From the data presented in Table 1, we have selected the product kids sun lotion SPF50 (product #6) and the ingredient ethylhexyl (octyl) methoxycinnamate (OMC) as the “worst case”. All other ingredients were excluded following the guidelines of the relevant Section 2.2.5. 2.3.3.1. Calculation of limits. Concentration, A 1 mg g−1 (0.10 % w/w in Table 1) Minimum batch size, C 3 × 106 g Sampling surface, D 10−2 m2 Recovery factor, F 87.6% (worst experimental case, see Section 2.7.3 and Table 3) Vessel surface, E 18.4 m2 Solvent rinse volume, G 20 l Result from Eq. (1) 1428 g per swab Result from Eq. (2) 131 mg l−1 (ppm) Final limit 10 mg l−1 (ppm) or g per swab This limit was calculated for the specific case only. In other equipment, with a different group of products, the results could differ. 2.4. Routine cleaning procedure
(1) ACF 100, 000G (2)
Washing of the manufacturing vessels is performed by means of a high pressure cleaning machine. The routine procedure is the following: The vessel is washed with deionized water and a suitable detergent, at a minimum of 85 ◦ C. The vessel
264
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is finally rinsed with hot (minimum 85 ◦ C) deionized (purified) water. Times for both cleaning procedures in this study have been set at 45 and 5 min, using two criteria: optically clean surfaces and no UV absorbance (200–400 nm) for a sample of the final rinse with purified water. 2.5. Sampling (for CVP purposes only) The whole CVP can be useful only if sampling has been designed and performed properly. The scope is to produce reliable results, chemical and microbiological. Samples are taken from the following: • Final rinse (purified water) of the equipment, at the end of the routine cleaning procedure, for full chemical (according to European Pharmacopoeia) and microbiological tests. • Surface of the equipment using swabs, after the final rinse, for microbiological test. • Solvent rinse (additional cleaning with water or organic solvent, i.e. ethanol, where ingredients to be determined can be dissolved) for determination of ingredients under investigation. The volume of the solvent must be relevant to the size of the equipment. • “Difficult to clean” surfaces, particularly on equipment not accessible to solvent rinse such as stirring axis, scraper, inner vessel surface (Table 2), using swabs after solvent rinse, for determination of ingredients under investigation. All samples should be
analyzed within 24 h, in order to avoid degradation products from the determinants. 2.6. Specifications after cleaning procedures • Visual cleanliness after final rinse (routine). • No microbiological contamination of final rinse and swabs (CVP). • No significant UV absorbance of final rinse (tentative maximum is the absorbance of 10 ppm solution of the ingredient under investigation, CVP). • Solvent rinse and surface swabs concentration must be better than the acceptance limits (Section 2.3.3, CVP). 2.7. Method 2.7.1. Instruments A UV–VIS spectrophotometer (Perkin-Elmer L2) was used for the assessment of the final rinse using quartz cuvettes having a 1 cm optical path. (Sections 2.4 and 2.6). A Varian Star LC system was used (UV detector 9050 and pump 9012) equipped with an autosampler (9100) with a 20 l loop and a C18 reversed phase column (Kromasil® 250 mm × 4.5 mm, 5 m packing material) in line with a similar pre-column (30 mm × 4.6 mm) for assessment of solvent rinse and swabs. The mobile phase consist of isocratic elution of a MeOH:H2 O solution (90:10, v/v) at a flow rate of 1.2 ml min−1 at ambient temperature. The detector was set at 305 nm.
Table 2 Analytical data and validation results for OMC as retrieved from liquid chromatographic analysis Batch number (kids lotion SPF 50)
Stirring axis (g per swab)
Scraper (g per swab)
Inner vessel surface (g per swab)
Solvent (EtOH) rinse (mg l−1 )
0105A 0111B 0112C 0112D 0112E 0201F 0201G 0202H
6.60 5.85 5.92 7.45 4.86 Nqa 4.21 5.12
6.90 7.11 3.59 6.27 5.77 6.88 6.12 5.44
8.42 6.36 4.38 7.77 Nq 9.32 Nq 5.43
7.25 6.26 Nq 4.69 Nq 7.00 Nq 3.81
Results after cleaning for OMC residual content after production of product #6. a Nq: non-quantifiable values (<3.34 mg l−1 ).
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2.7.2. Analysis of rinse and swabs by liquid chromatography The method that was used for the determination of sunscreen filters content (similar to those referred to in the literature) [12–15] was the same with the one used for routine analysis. This is an in-house method that was developed, validated and approved for FAMAR’s customers (multinational companies). Routine assay concentration of the ingredient OMC is 150 mg l−1 (ppm). The concentration of OMC in the product was 7.5% (w/w). Validation for linearity and precision at concentrations of 0.5, 1, 10, 50, 100, 150 mg l−1 (n = 6) was carried out and the determination of detection (DL) and quantitation limits (QL) were evaluated (Table 2). 2.7.2.1. Standard preparation. A working reference standard, from approved raw material (OMC, BASF,
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Germany) was used for all weightings. Approximately 100 mg of OMC was accurately weighed into a 100 ml volumetric flask and was dissolved in and diluted to volume with isopropanol. In order to make calibration measurements, the relevant volumes were pipetted from this solution into 100 ml volumetric flasks, mixed and diluted to volume with isopropanol. 2.7.2.2. Sample preparation. The solvent rinse is injected directly and swabs are given a 2 ml solvent rinse before injection. All tests have been performed in triplicate. 2.7.3. Recovery Recovery in this study means how well the residue can be retrieved from the equipment. Simulation of swab sampling was performed by placing solutions
Fig. 1. Liquid chromatograms of: (A) routine sample preparation for the determination of OMC in kids lotion SPF 50, batch 0112D, at attenuation 1024 and (B) solvent rinse residue after cleaning of the vessel, at attenuation 32. Chromatographic conditions are described in Section 2.
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4. Conclusions
Table 3 Recovery of OMC Cnominal (mg l−1 )
Ccalculated (mg l−1 )
1.00 10.00 50.00 100.0 150.0
0.88 9.15 47.70 101.35 150.50
± ± ± ± ±
0.003 0.02 0.22 0.26 0.23
Recovery (%) 87.6 91.5 95.4 101.3 100.3
± ± ± ± ±
0.3 0.2 0.4 0.3 0.2
of the ingredient under investigation on a stainless steel plate with dimensions equal to those of sampling (10 cm×10 cm = 10−2 m2 ), drying and recovery with the swab wetted with the solvent rinse. Range of tests: 1.00–150.0 mg l−1 . All tests have been performed in triplicate and the averages are shown in Table 3.
The results of samples after the routine cleaning procedure are well within limits with the assurance of the validated method used. The tentative limit of 10 mg l−1 can be considered as the final maximum acceptance limit. As all validation protocols after three consecutive determinations, a yearly monitoring can be conducted. Any deviations must be investigated through the correct use of washing and/or analytical procedures, as well as the nature of the next product (i.e. potential risks from accumulation of active ingredients). The approach of the 3-log reduction of residues can be proved to be valuable when the method used is not very sensitive.
3. Results and discussion References Analytical results obtained from the validation of the method (Table 2) and recovery (Table 3) showed that all assumptions and calculations made in the CVP proved that residues can be detected within the expected limits (rinse and swab concentration < 10 mg l−1 or g per swab, respectively). The analytical method used for determination of the residues is able to detect OMC down to 1.11 mg l−1 and to quantify >3.34 mg l−1 (Fig. 1). Linearity in the range 0.50–150 mg l−1 , A = 39,999 (±189) × C − 7971 (±13378), R = 0.99994 and precision at all calibration points, R.S.D. = 0.21–1.35% (<2.0%) assures that all values within this range are reliable. It must be clear that: only one sample is valid each time for the solvent rinse and each swab sample (out of three replicates) must be from different points. Standard deviation for these replicates is not applicable. As far as it concerns recovery, it is demonstrated that residues detectable by the analytical method within the range 1–150 mg l−1 can also be recovered by the selected method of sampling. The recovery range of 87.6–101.3% shows the good accuracy of the method. Considering the random errors of sampling at low concentrations, the recovery is very high and well accepted from the protocol (Section 2.3.1).
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