Pharmacokinetics and bioequivalence evaluation of cyclobenzaprine tablets

Case report: Treatment of cyclobenzaprine ingestion in two dogs with intravenous intralipid therapy

Introduction

The objective of this case series is to describe the clinical signs and outcome of cyclobenzaprine ingestion in two dogs treated with intralipid emulsion (ILE) and supportive care.

Case or series summary

Two dogs presented for evaluation of cyclobenzaprine ingestion. A 4-year-old female spayed Rat Terrier (dog 1) presented within 4 h of ingestion of cyclobenzaprine (between 9.7 and 25.9 mg/kg). The dog experienced abnormal behavior, agitation, tremors, tachycardia, and hypertension. There were no significant clinicopathological abnormalities. The dog was treated with ILE, cyproheptadine, and activated charcoal. All clinical signs resolved after treatment. A 5-month-old female intact mixed-breed dog (dog 2) presented after ingestion of an unknown amount of cyclobenzaprine 2-3 h prior to presentation. The dog experienced dull mentation, tremors, loss of gag reflex, tachycardia, and hypertension. There were no significant clinicopathological abnormalities. Orogastric decontamination was performed via gastric lavage, and activated charcoal was given via orogastric tube, followed by ILE. All clinical signs resolved after therapeutic intervention.

Discussion

This is the first report documenting clinical signs of cyclobenzaprine toxicity in two dogs followed by successful treatment with gastric emptying, ILE, and supportive care.

Development of Extended-Release Formulations Containing Cyclobenzaprine Based on Physiologically Based Biopharmaceutics Modeling and Bioequivalence Safe Space

The use of physiologically based biopharmaceutics modeling (PBBM) and bioequivalence safe space is increasingly common for immediate-release drug products. However, for extended-release (ER) formulations there are only a few examples of this application. In this study, we developed ER formulations containing cyclobenzaprine 15 mg, supported by PBBM and bioequivalence safe space. Four formulations were prepared, F1, F2, F3 (ER mini-tablet formulations) and F4 (ER tablet formulation), and the dissolution profiles were evaluated. The dissolution profile of the reference drug product was also evaluated and used to set a bioequivalence safe space. A PBBM was set up, evaluated, and used to predict the in vivo behavior of the formulations. The bioequivalence safe space was calculated to be between - 25% and + 75% of the k1 and Tlag values of the dissolution profile of the reference drug product when applying the first-order dissolution kinetic model. All time points of the dissolution profile of the ER mini-tablet formulation F2, were within the safe space, and was approved in 10 of 10 trials of crossover virtual bioequivalence studies. Based on the PBBM strategy and bioequivalence safe space, it was possible to develop an ER mini-tablet formulation virtually bioequivalent to the reference drug product, even though this formulation failed the f2 test.

A Novel Method for Determination of Cyclobenzaprine in the Different Matrixes by UHPLC-DAD: Application to Real Human Plasma and Pharmaceutical Formulations

This study presents a novel and efficient method for determining of cyclobenzaprine (CBP) in human plasma and tablets using simple liquid-liquid microextraction and ultra-high performance liquid chromatography-diode-array detector. The developed method was optimized and validated for selectivity, linearity, precision, accuracy, limit of detection (LOD) and limit of quantification (LOQ). The chromatographic separation was achieved using a C18 column with a mobile phase consisting of a mixture of deionized water containing 0.1% TFA and methanol (30:70, v:v) at a flow rate of 1.0 mL/min. The extraction process provided high-efficiency recovery of CBP with a small plasma volume (%94.3). The method showed good linearity within the concentration range of 0.005-10 μg/mL, with a correlation coefficient of 0.999. The LOD and LOQ values were found to be 0.0013 and 0.005 μg/mL, respectively. The intra- and inter-day %RSD were <8%, and %RE were ranged from -0.50 to 0.01%. The proposed method was successfully applied to the analysis of CBP in real human plasma samples and tablets, indicating its applicability in clinical and pharmaceutical research. In conclusion, the simple, low cost, high sensitivity and rapid nature of this method make it an attractive option for the quantification of CBP in human plasma and pharmaceutical dosage forms.

Treatment of comatose patient from cyclobenzaprine overdose with therapeutic plasma exchange

We present a case of a 15-year-old female who was admitted in a comatose state with no spontaneous respiratory effort and absence of brainstem reflexes after cyclobenzaprine ingestion. Due to severe presentation and recent ingestion of high plasma protein binding medication with long half-life, therapeutic plasma exchange (TPE) was performed and resulted in full neurological recovery. This case explores the role of TPE as an effective treatment option for life-threatening cyclobenzaprine overdose. TPE is generally beneficial for drugs that have a low volume of distribution and high plasma protein binding. Cyclobenzaprine is known to have a relatively high volume of distribution. However, in the case of drug intoxication with relatively high-volume distribution, high protein binding, and long half-life, TPE could be effective if it is conducted promptly.