Comparison of the analysis of delta 9-tetrahydrocannabinol capsules by high-performance liquid chromatography and capillary gas chromatography

Stability of dronabinol capsules when stored frozen, refrigerated, or at room temperature

Purpose

Results of a study to determine the 90-day stability of dronabinol capsules stored under various temperature conditions are reported.

Methods

High-performance liquid chromatography (HPLC) with ultraviolet (UV) detection was used to assess the stability of dronabinol capsules (synthetic delta-9-tetrahydrocannabinol [Δ9-THC] mixed with high-grade sesame oil and other inactive ingredients and encapsulated as soft gelatin capsules) that were frozen, refrigerated, or kept at room temperature for three months. The dronabinol capsules remained in the original foil-sealed blister packs until preparation for HPLC–UV assessment. The primary endpoint was the percentage of the initial Δ9-THC concentration remaining at multiple designated time points. The secondary aim was to perform forced-degradation studies under acidic conditions to demonstrate that the HPLC–UV method used was stability indicating.

Results

The appearance of the dronabinol capsules remained unaltered during frozen, cold, or room-temperature storage. Regardless of storage condition, the percentage of the initial Δ9-THC content remaining was greater than 97% for all evaluated samples at all time points over the three-month study. These experimental data indicate that the product packaging and the sesame oil used to formulate dronabinol capsules efficiently protect Δ9-THC from oxidative degradation to cannabinol; this suggests that pharmacies can store dronabinol capsules in nonrefrigerated automated dispensing systems, with a capsule expiration date of 90 days after removal from the refrigerator.

Conclusion

Dronabinol capsules may be stored at room temperature in their original packaging for up to three months without compromising capsule appearance and with minimal reduction in Δ9-THC concentration.

The value of analytical assays that are stability-indicating

It is essential to validate an assay with regards to its precision, accuracy, reproducibility, selectivity and robustness. In pharmaceutical research, in addition to these requirements, an assay is often required to be proven beyond doubt to be stability-indicating. A stability-indicating assay is one that can accurately and selectively differentiate an intact drug from its potential decomposition products. An assay that fails to meet this requirement would produce stability data that are inaccurate and misleading. This concept could be applied to other fields of research, such as clinical laboratory chemistry where accurate and reliable clinical data are imperative in the diagnosis and following-up of diseases. In this study, we employed an amperometric HPLC assay developed for the measurements of urinary catecholamines and metanephrines to illustrate the validation process of this assay with regards to its stability-indicating capacity. The implications of this study are also discussed.

Determination of delta 9-tetrahydrocannabinol in human blood and saliva by high-performance liquid chromatography with amperometric detection

A rapid, sensitive and selective determination of delta 9-tetrahydrocannabinol (THC) in human plasma, serum and saliva was developed with high-performance liquid chromatography with electrochemical detection. Initially, samples were deproteinized, followed by a one step liquid-liquid extraction. Samples were measured by high-performance liquid chromatography with electrochemical detection with 4-dodecylresorcinol as the internal standard. The minimal detectable limit for THC in biological samples was ca. 1 ng/ml with a signal-to-noise ratio greater than 3, corresponding to an on-column sensitivity for THC of ca. 0.5 ng. The detector was operated at + 0.90 V vs. Ag/AgCl and exhibited linearity over a concentration range of 1-150 ng/ml with correlation coefficients of the standard curves greater than 0.99.

Review of analytical methods for identification and quantification of cannabis products

About 100 recently published original papers, reviews, books and other communications concerning cannabis (hashish, marijuana) constituents have been reviewed with the aim of summarizing the status of analytical detection and quantitation. Detailed protocols of standard analytical methods are compared in order to recommend uniform methods for field and forensic samples and also to provide guidance to less experienced analysts in countries where cannabis sativa occurs (T. Maylon.In Big Deal: The Politics of the Illicit Drug Business, the Cannabis Commodity Market, pp. 63-107. Guernsey, London.). Because of its importance, there has been an increasing number of investigations of the chemical, botanical, pharmacological, clinical and sociological aspects of the marijuana (hashish) problem. Since analytical techniques have improved substantially during the last 10 years, many papers have been published containing a variety of methods for detection and quantification of cannabis constituents. Since the analytical situation is becoming increasingly confused and because many of the journals are unavailable in less developed countries, the aim of this paper is to give an overview of existing analytical techniques and to attempt to distinguish practical and effective methods from those which are complex or which provide questionable results.