Introduction:

Depression is one of the parts of mental disorder which is affecting millions of people worldwide. [6] The logical analytical approach used in clinical and forensic toxicology for the identification of one or more Antidepressant Drugs as a cause of intoxication is largely based on both simple and fast screening methods which cover their extraction and identification including detection of their possible metabolites is been tried to reviewed.

Antidepressant: Types & Functions

Antidepressant drugs cover many varieties of drugs having different modes of actions like [16] etc.

Adverse effects

Antidepressants are supposed to increase the risk of suicidal thinking and behavior in children accompanying other disorders like depressive and psychiatric disorders. [17] [18] [19] The European Medicines Agency showed warning on the use of Antidepressants which might be increased the risk of suicidal behavior in children and adolescents. [31] TCAs and MAOIs can produce similar kind of side effects like Tachycardia, blurred vision, urinary retention, cardiovascular effects , hypotension, respiratory depression, coma etc. [4] Thus, these drugs may be responsible for the fatality and intoxication and can produce severe effects. Also their growing rate all over the world may show threatening effects which is the matter of global concern. Thus, it’s increasing prescription rate and adverse effects resulting in a growing interest for determination methods in the Clinical and Forensic field.

Biological Samples use for the Screening of Antidepressant Drugs

Biological samples are the basic requirement of Forensic and Clinical Toxicology as it solve several related questions which make basis of judgement, consultation and expertise for the above two fields. The matrices generally encountered for analysis are urine [34], hair, nails, vitrous humour etc.

The most important biosample used for analytical purposes is Blood. It is a liquid connective tissue of the body composed of different kinds of blood cells suspended in a fluid called plasma. Blood (plasma, serum) is one of the best choices for quantitative and qualitative measurements of drugs of interest because pharmacological or toxicological effects correlate more effectively with their concentrations in blood. [42]

Another important biological sample is Urine which is a widely used specimen employed for screening, identification and testing of unknown drugs, forms in high amount, readily available, easy to collect and contains much useful information about the major metabolic functions of the body. [43]

Taking Forensic concept in postmortem cases if the positive finding of drug occurs in urine shows that the detected substance or it’s parent compound might be present in the body some time before death [48]

A next alternative to the blood and urine specimen found is Oral fluid for their applications in therapeutic and toxicological drug monitoring [54]

When analytical studies get concern with long duration of exposure to the detection window Hair could be as a best biological matrix for the identification and analysis of drugs. It is supposed that drugs or chemicals enter in to hair by passive diffusion from blood capillaries into growing cells and the mechanisms of substance incorporation, analytical methods, result interpretation and practical applications of hair analysis has been well reviewed showing practical utility of hair analysis. [62]

Except from all the above given matrices one very precise and rarely encountered biological sample is Vitreous Humor. It’s a fluid found between the lens and retina of the eye proved to be the best choice for analytical examinations as it is relatively well isolated and protected from putrefaction. Two different fatality cases were reported where the extraction of drugs is done from Vitreous humor. One case has been reported of citalopram fatality where the extraction of drug is done from Vitreous humor yeilding concentration of citalopram (SSRI) less than 0.04mg/L and in second case venlafaxine fatality is reported where postmortem analysis revealed the concentrations of Fluoxetine (SSRI) and it’s metabolite Norfluoxetine as 5.2 mg/l and 2.2mg/l respectively. [64]

Other than these specimens, body tissues like liver [71], cerebrospinal fluid etc. canalso encounter for toxic and therapeutic drug monitoring biological matrices.

Techniques for Sample Preparation

Several methods have been published for the determination of one or more antidepressants in biological fluids for therapeutic monitoring or for toxicological purposes. For making biological samples suitable for analytical purposes some treatments should be given to overcome the matrix effects such that the other materials should not interfere with the analytical separation that is the extractability of the analytes in the sample inturn the results of the analysis. [96] These kinds of techniques are rapidly gaining acceptance in bioanalytical applications to reduce both time and labor required to produce bioanalytical results. Thus we can say that these methods give a high selectivity and sensitivity over a wide dynamic range and contribute in formulating very fine detection techniques.

Some Commonly Prescribed New Generation Antidepressant Drugs and their Metabolites

Several new antidepressants that inhibit the Serotonin (SERT) and Norepinephrine transporters (NET) have been consistently use for therapeutic purposes. [108] are showing below.

Sertraline is an effective and highly utilized SSRIs group of drug and “it’s principle metabolite is desmethylsertraline.” [41]

Another SSRIs group of Antidepressant drug, Fluoxetine has been used worldwide in the therapy of major depression. (3) “It is primarily metabolized via N-demethylation by the [117]

Citalopram is a selective and potent serotonin reuptake inhibitor. [78]

Another very important group of Antidepressant drug is SNRIs which includes drugs like Venlafaxine which inhibits serotonin, noradrenaline, and to a lesser extent dopamine reuptake. [39]

In the majority of published analytical methods for determination of Antidepressant drugs, gas chromatography and high-performance liquid chromatography, in combination to different kinds of colums operating under different separation conditions, mobile phases and detectors has been used. These were tried to review in the table given below. With high-performance liquid chromatography the analysis is done by using different kinds of detectors like Fluorescence detector, UV detector, Mass detectors etc. For ex. a high-performance liquid chromatographic method is described for the determination of serotonin and norepinephrine reuptake inhibitor (SNRI) in human plasma where Fluorescence detector was used. [140] A survey of most recent multiresidue analytical methods developed for the determination of different kinds of Antidepressant drugs in different types of biological test matrices with their specific cleanup procedures including the choice of mobile phase, stationary phase, detector system and validation data is summarized in the tabular form below.

TABLE

Abbreviations:APCI atmospheric pressure chemical ionisation, ESI eletrospray ionisation, LLE liquid-liquid extraction, LOD limitation of detection, LOQ limit of quantification, SIM single ion monitoring, SPE solid-phase extraction, SRM selected reaction monitoring , ESI electron spray ionization, UV ultraviolet, FD fluorescence detector, LC_TMS liquid chromatography tandom mass spectrometry, LC_MS, GC_MS gas chromatography mass spectrometry, RP-HPLC reverse phase high performance liquid chromatography.

Thus, this table is framed for the comparative study of the major analytical approaches used in the detection and identification of Antidepressant Drugs and their metabolites in different biological matrices in order to develop the new methods with the aim to increase the sample throughput and to improve the quality of analytical methods. Thus, analytical methods for the detection of ADs and their metabolites in biological matrices are of interest in the field of forensic toxicology which involves the analysis of drugs and poisons in biological specimens and interpretation of the results to be applied in a court of law. Several analytical methods have been developed for analysis of these antidepressants in biological matrices. These methods provide a good precision and accuracy over the entire analytical range and allowing the development of very rapid and efficient analytical methods by using newer kind of analytical techniques.

Conclusion:

As the subject of Antidepressants toxicity is evolving, newer methods for their analysis are also evolving. However, some classes of Antidepressants drugs are less toxic and well tolerated but can lead to Toxic or Fatal Drug interaction. The research in this field is very active and results in a large number of papers published every year. Therefore they may be encountered in many Clinical and Forensic cases. Therefore, this review is mainly aimed to target latest analytical and instrumental methods used for detection and characterization of Antidepressant drugs and their metabolites in biological test matrices in turn focus on their toxic as well as therapeutic aspects which would be definitely prove to be helpful in future research and still there is lots of work required in this area as it’s prescription rate and toxicity is evolving day by day all over the world and by using non-destructive and sophisticated newer instrumental techniques we can also built a new strategy of examination and investigation for the drugs of interest. However, in this study, a decision about whether a study’s findings are positive or negative cannot always be based strictly on the primary outcome measure. Future trials should also consider, using different kinds of detecting techniques and methods which would allow for easier comparison and interpretation of results across studies as the subject is of global concern and despite the success of such methods there is a continuing need for sustained innovations. Thus, future work in this area will definitely prove to be a promising from both clinical as well as from forensic prospect.