D-731

5-Hydroxytryptophan Determination by HPLC using UV-Vis Spectroscopy

Section D — Laboratory Operations and Specifications Revision 5 8 pages

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1.0 Purpose 
 
 The purpose of this procedure is to describe a method for the quantitative analysis and
 
 identification of 5-hydroxytryptophan (5-HTP) in finished products and raw materials using
 HPLC coupled with UV/VIS spectrophotometry. 
 
 2.0 Scope 
 
 This procedure applies to the quantification and identification of 5-HTP. Some excipients and
 dietary ingredients used in the finished products can interfere with the analysis of 5-HTP.
 
 3.0 Responsibility 
 
 3.1 It is the responsibility of QC and Analytical Chemists to follow this procedure.
 
 3.2 It is the responsibility of QC Laboratory Management to implement this procedure and
 to ensure that the procedure is being followed. 
 
 3.3. It is the responsibility of QC Laboratory Management and/or Analytical Development to
 
 keep this procedure aligned with current practices. 
 
 4.0 Definitions 
 
 4.1 ACN - Acetonitrile 
 
 4.2 HsPOs4- Phosphoric Acid 
 
 4.3. HeO- Water (> 18.2 MQ:cm) 
 
 4.4 5-HTP — 5-hydroxytryptophan 
 
 4.5 QC — Quality Control 
 
 4.6 CofA — Certificate of Analysis 
 
 
 

[SOP 

 Standard Operating Procedure SOP No | Rev 
 5-Hydroxytryptophan Determination by HPLC D-731 5 | Page 2 of 8 
 
 coupled with UV/VIS Spectroscopy 
 
 4.7 HPLC - High Performance Liquid Chromatography 
 
 4.8 UV/VIS — Ultraviolet and Visible Spectroscopy 
 
 5.0 References 
 
 a MV-LAB-13-033, Protocol, Validation: 5-Hydroxytryptophan Determination by HPLC
 
 5.2. D-793, SOP, Cryogenic Grinding of Chewable Gels 
 
 6.0 Reagents, Supplies, Glassware and Equipment 
 
 6.1 Reagents: all reagents are HPLC grade or better. 
 
 6.1.1 H2O 
 
 6.1.2 ACN 
 
 6.1.3 H3PO4 
 
 6.1.4 5-HTP reference standard 
 
 6.2 Supplies and Glassware 
 
 6.2.1 HPLC vials, 12mm X 32mm with screw cap enclosures w/ septa. 
 
 6.2.2 Mobile phase containers 
 
 6.2.3 Volumetric glassware as required by sample and standard preparations
 
 6.2.4 50mL and 100mL beakers 
 
 6.2.5 200uL, ImL, and 10mL pipette tips 
 
 6.2.6 10mL plastic luer lock syringe 
 
 6.2.7 0.2 or 0.45um Nylon syringe filters 
 
 6.2.8 22mL screw cap vials 
 6.2.9 HPLC vials, 12mm X32mm with screw cap enclosures w/ septa 
 
 6.2.10 Micro centrifuge tubes 
 
 6.2.11 Weigh Paper and weigh boats 
 
 
 

[SOP 

 Standard Operating Procedure SOP No | Rev 
 5-Hydroxytryptophan Determination by HPLC D-731 5 Page 3 of 8 
 coupled with UV/VIS Spectroscopy 
 
 6.3 Equipment 
 
 6.3.1 Suitable gradient HPLC system consisting of a pump, autosampler, column oven
 and UV/VIS detector with a chromatographic data handling system
 
 6.3.2 Analytical Balance 
 
 6.3.3 Vortex 
 
 6.3.4 Stir Plate 
 
 6.3.5 Wrist action shaker 
 
 6.3.6 200uL, ImL, and 10mL pipettes 
 
 6.3.7 Microcentrifuge 
 
 7.0 Procedure 
 
 tl Mobile Phase and Buffer Preparation 
 
 TAbl Mobile Phase A - 0.1% H3PO4 in H20 
 
 7.1.1.1 Transfer 1000 mL H20 to a suitable container. 
 
 7.1.1.2 Add 1.0 mL H3POs, and mix well. 
 
 7.1.1.3 Scale as necessary. 
 
 712 Mobile Phase B - 0.1% H3PO4 in ACN 
 
 7.1.2.1 Transfer 1000 mL ACN to a suitable container. 
 
 7.1.2.2 Add 1.0 mL H3POs, and mix well. 
 
 7.1.2.3 Scale as necessary. 
 
 FallD Diluent- Mobile Phase A 
 
 72 Standard Preparation 
 
 721 The linear range of the analytical method is 0.01 mg/mL — 0.4 mg/mL. The
 
 standard and sample preparations must be within this range. 
 
 
 

[SOP 

 Standard Operating Procedure SOPNo | Rev 
 
 5-Hydroxytryptophan Determination by HPLC D-731 5 Page 4 of 8 
 coupled with UV/VIS Spectroscopy 
 
 T22 The standard is prepared by weighing no less than the minimum weight of the
 
 analytical balance, then bring up to two thirds their final volume in an appropriate
 volumetric flask using Diluent. Mix on a wrist action shaker for 30 minutes then
 
 inspect to ensure complete dissolution. Once the standard is fully dissolved, bring
 
 standard to final volume before using. 
 
 723 To manage large volumes, the standard can be initially prepared at a higher
 concentration and further diluted into the linear range using Diluent. Dilutions
 
 can be made using volumetric glassware and/or adjustable pipettes. Working
 standard concentrations will approximate the concentration expected to be found
 
 in the product being tested based on the sample dilution and calculated from the
 
 label. Final dilutions may be prepared directly in HPLC vials.
 
 Ts Sample Preparation 
 
 Specific sample testing details are provided in each products profile. If a specific
7.3.1 testing details section is not available, then follow preparation procedure as

 described below, maintaining concentration within the linear range listed above.
 
 For raw materials: weigh no less than 20 mg into a suitably sized volumetric flask
 Tove 
 of no less than 25 mL volume to generate an analyte concentration that is within
 the validated linearity range. Dilute to 2/3 flask volume using Diluent, shake
 
 mechanically for 30 min, and dilute to volume using Diluent. 
 
 For solid and liquid dose finished products: Combine and homogenize no less
 Tai 
 than ten dosage units. Based on the label claim and weight per dose, weigh no
 less than 50 mg of the pooled dosages into a suitably sized volumetric flask of no
 
 less than 25 mL to generate an analyte concentration that is within the validated
 linear range. Dilute to 2/3 flask volume using Diluent, shake mechanically for 30
 
 min, and dilute to volume using Diluent. 
 
 For chewable gels (gummies), homogenize at least 10 dosage units according to
7.3.4 the procedure outlined in D-793 Cryogenic Grinding of Chewable Gels. Quickly

 weigh a portion of the pooled and homogenized dosages into a beaker. Use several
 
 
 

[SOP 

 Standard Operating Procedure SOP No Rev 
 5-Hydroxytryptophan Determination by HPLC D-731 
 Page 5 of 8 
 coupled with UV/VIS Spectroscopy 
 small portions of Diluent to completely transfer the sample into a suitably sized
 
 volumetric flask to generate an analyte concentration that is within the validated
 
 linear range. Dilute to 2/3 flask volume using Diluent, shake mechanically for 30
 min, and dilute to volume using Diluent. 
 
 7.3.5 To manage large volumes, the sample can be initially prepared at a higher
 
 concentration and further diluted into the linear range using Diluent. Dilutions
 
 can be made using volumetric glassware and/or adjustable pipettes. Dilutions can
 be prepared in HPLC vials. 
 
 7.3.6 Centrifuge a portion of the final sample at 10,000 rpm for 5 min to remove
 
 particulates prior to HPLC analysis. Alternatively, the sample may be filtered
 through a 0.45 um membrane discarding the first 2-3 mL. 
 
 8.0 Test Conditions 
 
 8.1 Gradient-multistep 
 
 8.1.1 Time %A %B 
 
 0.00 98 
 
 5.00 98 
 
 7.00 60 
 
 7.10 98 
 
 13.0 98 2 
 
 8.2 Column- Luna 5um C5, 100A, LC column, 150mm X 4.6mm or equivalent 
 
 8.3 Flow Rate- 1.0mL/min 
 
 8.4 UV detection- 225nm 
 
 8.5 Injection volume- 20uL 
 
 8.6 Column Temperature- 30°C 
 
 8.7 Recommended 3-D Spectral Range- 210nm to 330nm 
 
 
 

[SOP 

 Standard Operating Procedure SOP No | Rev 
 5-Hydroxytryptophan Determination by HPLC D-731 5 Page 6 of 8 
 coupled with UV/VIS Spectroscopy 
 
 8.8 Retention Time — about 4.5 min 
 
 8.9 | Recommended Sequence 
 
 8.9.1 Make at least 2 injections of the diluent. 
 
 8.9.2 Make five (5) injections of Standard Solution. 
 
 8.9.3 Make a single injection of each Sample Preparation. 
 
 8.9.4 Make a single injection of the Standard Solution after every six (6) samples and
 at the end of the run. 
 
 8.10 System Suitability Requirements 
 
 8.10.1 The %RSD of five (5) injections of the Working Standard is NMT 5.0%.
 
 8.10.2 The %RSD of all injections of the Working Standard is NMT 5%.
 
 8.11 Example calculations for determining finished product % label or raw material % purity
 
 8.11.1 % assay= = x SVetia x ESA K“*LA x ane 
 
 Ry Sample peak area 
 
 Rs Mean standard peak area 
 
 Wtesta Weight of reference standard in mg 
 Volume of the standard preparation accounting for dilutions in mL
 Vsea 
 
 Purity of the reference standard in decimal format 
 
 Sample amount in mg 
 
 Volume of the sample preparation accounting for dilutions in mL
 
 Serving size: Weight of a single dosage unit in mg or | for raw
 
 materials. 
 
 LA 
 Label amount in mg per dose or 1 for raw materials 
 
 
 

[SOP 

 Standard Operating Procedure SOP No | Rev 
 
 5-Hydroxytryptophan Determination by HPLC D-731 5 | Page 7 of 8 
 coupled with UV/VIS Spectroscopy 
 
 8.12 Example Chromatography 
 
 8.12.1 Blank 
 
 DAD1A,Sig=225.0,4.0 Ref=360.0,100.0 
 3000+ 
 2500+ 
 -2000/ 
 5004 
 1000+ 5on 
 500+ 
 > 
 06 1 1.5 2 25 3 3.5 4 45 5 65 6 656 7 7.6 8 85 9. 9.5 1010.56 11 11.5 12 12.5 13
 Time [min] 
 8.12.2 Standard 
 DAD1A,Sig=225.0,4.0 Ref=360.0,100.0 
 2 
 3000+ rs 
 25004 = 
 -70004 
 5004 
 1050000++ ~N~ SE2 Rco eeQs 
 X al. all 
 05115225 335 445 5 55 6 65 7 75 8 85 9 95 10 10.5 11 11.5 12 12.5 13
 Time [min] 
 8.12.3 Sample 
 
 DAD1A,Sig=225.0,4.0 Ref=360.0,100.0 
 3500 3 
 30004 bs 
 25004 a 
 ed 
 5007 = 
 10007 On 
 -O 5007 = pig his j 
 vy ’s a 
 1 : ‘ 
516.1 ATH-5

 972.6“ 829.64 599.74 608.8 1 
 472 ena g§ 
 s 
 aro 
 esa 
 TQA 
 1 
 S 
 ax 
 5 665 7 75 8 85 9 95 1010511 11.5 12 12.5 13 
 Time [min] 
 224.54}4 
 rO 45 5 
 

[SOP 

 Standard Operating Procedure SOP No | Rev 
 5-Hydroxytryptophan Determination by HPLC D-731 5 Page 8 of 8 
 coupled with UV/VIS Spectroscopy 
 
 10.0 Revision History 

| Rev | Date | Description of Changes | CCR # | By |
|-----|----------|------------------------|-------|----|
| 1 | 06/17/13 | New | 13-0416 | B. Johns |
| 2 | 07/01/15 | eens review: updated SOP format. Updated HPLC method | 15-0585 | Holeine |
| 3 | 01/02/19 | Scheduled review: updated SOP format, stability requirement, weight requirement, and number of pooled tablets. Updated for consistency with current methods and lab practices. 4 ORME A A d d d d e e d d r ex e a c m o p m l m e e n ch d r e o d m a s t eq o u g e r n a c p e h . y . A d R d e e m d o v s e ys d t e e x m t s r u a i n t e a o bi u l s i t i y n f s o e r ct m i a o t n i . on. Cees Se Sesias | 19-0008 | J. Maignan |

 Narrowed the range for spectral match. 
 Removed unnecessary information and aligned with current SOP 
 5 05/22/23 format. Added instruction to follow test details containing product CC-23-0252 | S. Sassman
 specific sample preparation. Added specific sample prep instructions
 for different dosage forms. Updated logo.