Single-Laboratory Validation to Extend the Scope of AOAC Official MethodSM 2015.06 to Indian Infant, Child, and Adult Nutritional Matrixes

BACKGROUND

AOAC Method 2015.06 is a Final Action Official MethodSM for the determination of 12 elements (Na, Mg, P, K, Ca, Cr, Mn, Fe, Cu, Zn, Se, and Mo) in infant formula and adult nutritional products, based on inductively coupled plasma (ICP)-MS. Currently, its scope does not include certain kinds of formulations used in India. The method would likely be used more in Indian laboratories if its performance were characterized on Indian matrixes.

OBJECTIVE

In this study we describe a typical single-laboratory validation (SLV) exercise designed to characterize the precision and accuracy of AOAC Method 2015.06 for common Indian nutritional matrixes so that the scope of the method can be extended to include them.

METHOD

Six matrixes specific to the Indian market were carried through an SLV and the Standard Method Performance Requirements (SMPRs®) previously published for this method were used to evaluate the results.

RESULTS

The method demonstrated typical repeatability (<5% RSD), and intermediate precision (5-8% RSD) on the Indian matrixes, with very few exceptions. Accuracy was demonstrated by overspike recoveries in the range of 90-110% over 3 days for the Indian matrixes, as well as excellent agreement with previously published results for three additional matrixes tested. Some of the new Indian matrixes required alternate sample preparation procedures versus the usual reconstitution prescribed by the SMPRs.

CONCLUSIONS

The SLV results showed that AOAC Method 2015.06 can be extended to include these Indian matrices.

HIGHLIGHTS

The two special sample preparation procedures can now be considered validated.

Single-Laboratory Validation of AOAC Official Method 2011.10 for Vitamin B12 in 'Indian' Infant and Pediatric Formulas and Adult Nutritionals

BACKGROUND

Ensuring the quality of infant and pediatric formulas and adult nutritionals is of utmost importance for the health and safety of rapidly urbanizing Indian population. B12 is an important water-soluble vitamin, which is fortified externally in such nutritional formulations. The Bureau of Indian Standards (BIS) has a recommended microbiological assay-based method for determination of vitamin B12 that is not precise and accurate enough to meet the label claim requirements of infant, adult, and/or pediatric nutritionals. The AOAC Official Method 2011.10 was originally developed under the AOAC Stakeholder Panel on Infant Formula and Adult Nutritionals (SPIFAN) for the determination of vitamin B12 in infant and pediatric formulas and adult nutritionals. However, those SPIFAN matrixes did not contain malt and other indigenous cereal and legume flour (with or without cocoa powder), which are commonly found in Indian formulations. Thus, there is a need to replace this method with a more precise and accurate method.

OBJECTIVE

This study was undertaken to validate the AOAC Official Method 2011.10 on vitamin B12 in 'Indian' infant and pediatric formulas and adult nutritionals.

METHODS

The single-laboratory validation (SLV) of AOAC Method 2011.10 was carried out as per the AOAC Guidelines in six Indian pediatric and adult nutritional formulas to verify its fitness for purpose. Cobalamin in the sample was converted to cyanocobalamin on treatment with potassium cyanide. The sample was then subjected to clean up through a C18 cartridge. Vitamin B12 in the eluted extract was separated from other components using size-exclusion column chromatography followed by a C18 column. The HPLC analysis was carried out at 550 nm.

RESULTS

Diastase treatment and C18 solid-phase extraction cleanup satisfactorily removed the matrix interference. The relative standard deviation of the determined values in 30 samples each from 6 selected Indian products and NIST SRM 1849a was <20%. The average recoveries for the spiked recovery samples ranged from 91.75 to 101.14%.

CONCLUSIONS

Method 2011.10 met the standard method performance requirements set forth by the AOAC SPIFAN. Therefore, we recommend the Method 2011.10 for adoption as the BIS official method for the analysis of vitamin B12 in 'Indian' infant and pediatric formulas and adult nutritionals.

HIGHLIGHTS

This was the first SLV project that the AOAC India section undertook to extend the scope of the AOAC Method 2011.10 for vitamin B12 analysis by validating it in 'Indian' infant and pediatric formulas and adult nutritionals.

Malignant nonfunctioning pheochromocytoma occurring in a mixed multiple endocrine neoplasia syndrome

OBJECTIVE

To present the first documented case of malignant nonfunctioning pheochromocytoma occurring in a mixed multiple endocrine neoplasia (MEN) syndrome.

METHODS

We describe the personal and family history of a 34-year-old man with headaches, increased serum prolactin levels, and hyperparathyroidism and review the details of his clinical course and treatment.

RESULTS

After diagnosis of a prolactinoma, bromocriptine therapy was implemented but eventually discontinued by the patient when severe headaches recurred. A transsphenoidal resection of a prolactinoma was performed; the patient continued to have abnormally high serum prolactin levels. Subsequent left lower flank pain prompted an exploratory laparotomy, and a left nephroad-renalectomy was performed. Pathologic examination disclosed a 1-cm tumor, consistent with malignant pheochromocytoma. Electron microscopy demonstrated neurosecretory granules. A hypercoagulable state complicated the course postoperatively. Despite chemotherapy, extensive metastatic disease ensued, and the patient died.

CONCLUSION

Although pheochromocytomas are usually associated with MEN type IIA and type IIB, this patient had a malignant pheochromocytoma, without the usual clinical and biochemical manifestations, in the setting of MEN type I.

Spectrophotometric determination of sulphacetamide

A new rapid selective spectrophotometric method for the determination of sulphacetamide is described. The drug forms a orange-yellow colored complex with Cerium(IV) in sulfuric acid media which is extracted into ethyl acetate. The complex exhibits a maximum absorbance at 440 nm with a molar absorptivity of 3 x 10(2) 1 mol-1 cm-1. The system obeys Beer's law in the concentration range of 0.07-1.1 mg of sulphacetamide. The various parameters for the optimum extraction conditions are discussed. The method is applied to the determination of sulphacetamide in dosage forms.