Plasma Drug Levels Research Articles

Using in silico methods to determine optimal tapering regimens for decanoate-based long-acting injectable psychosis drugs.

Reducing the dose of psychosis drugs in a gradual hyperbolic manner may minimise withdrawal effects and risk of relapse. There is presently limited guidance on tapering decanoate-based long-acting injectable dopamine antagonists (LIDAs). We aimed to apply hyperbolic principles of tapering to the decanoate-based LIDAs flupentixol, zuclopenthixol and haloperidol to develop withdrawal regimens. We used in silico methodology to predict plasma drug levels and D2 occupancy for different LIDA regimens. Existing pharmacokinetic and receptor occupancy data from nuclear neuroimaging studies were used to power modelling. Abrupt discontinuation was examined as a potential strategy, and dose reduction was modelled with pre-defined constraints used in similar work of 10 (fast regimens), 5 (moderate) and 2.5 (slow) percentage points of D2 occupancy change per month. Abrupt discontinuation of decanoate-based LIDAs leads to excessive change in D2 occupancy which violated our pre-defined constraints, potentially resulting in withdrawal symptoms and increased risk of relapse. Reduction of LIDA dose allowed hyperbolic reduction in plasma level consistent with imposed constraints on receptor occupancy reduction rate. For equivalent per-weekly LIDA dosing, more frequent administration allowed a more gradual reduction of D2 occupancy. However, switching to oral forms is required to continue hyperbolic tapering to full discontinuation; reduction to zero using only LIDA produces too large a reduction in D2 occupancy. Guidance for reduction and cessation of LIDAs according to slow, moderate and fast criteria is provided. Abrupt cessation of decanoate LIDAs is not consistent with gradual hyperbolic tapering, despite their longer half-lives compared with oral formulations. Reduction to the point of full discontinuation can only be achieved by switching to oral therapy to complete the taper. These results are limited by the in silico and theoretical nature of the study, and there is a need to confirm these findings through real-world observational and interventional studies.

Frovatriptan succinate intranasal delivery for brain targeting – in vivo study.‎

Muco-adhesive gel formulations are advantageous in extending the stay at the nasal ‎absorption place, promoting drug absorption. Frovatriptan succinate (FVT) exhibits a 35% ‎oral bioavailability and undergoes hepatic metabolism, making it a viable candidate for ‎nasal delivery. This study aimed to assess novel FVT intranasal formulation for brain ‎targeting in rat animal models. A total of 78 female rats (Rattus norvegicus domestica, ‎Wister albino rats) were randomly divided into three groups: group A (considered a ‎negative control), group B (includes 36 rats given FVT IV solution), and group C (includes ‎‎36 rats given FVT binary ethosome in situ gel intranasally). Drug levels in plasma and brain ‎tissue were measured using HPLC methods. In all periods, for both brain tissue ‎concentrations of FVT and the brain-to-plasma ratio of FVT, it was significantly higher in ‎Group C compared to Group B. Nasal administration of FVT showed higher brain Tmax, ‎Cmac, and AUC compared to IV administration, with 239.83% higher accumulation of FVT ‎when nasal formulation used compared to IV administration. In conclusion, in situ gel has ‎demonstrated its efficacy in facilitating the delivery of frovatriptan succinate via the nasal ‎route. The convenience of the administration process, combined with reduced frequency of ‎administration, contributes to improved patient adherence‎‎‎.

Anticoagulation management in elderly patients with proximal femur fractures- overview of current concepts.

Proximal femur fractures (PFF) are common injuries in elderly patients and can have considerable effects on their quality of life, morbidity, and mortality. Due to pre-existing comorbidities, the prevalence of anticoagulated patients is increasing. The right timing for surgery and perioperative anticoagulation treatment remains controversial. This overview aims to summarize current practices in the pre- and postoperative anticoagulation management and the recommended time to surgery in elderly patients with PFF. Time to surgery for anticoagulated patients is often prolonged due to worries about serious perioperative bleeding and higher transfusion demands. But the delay of surgical PFF treatment increases the risk for perioperative complications like pulmonary embolism, pneumonia, deep vein thrombosis and urinary tract infections. Early surgery can be achieved with a consistent and interdisciplinary perioperative anticoagulation management. Antiplatelets do not have to be discontinued and surgery should be performed early without delay. For patients taking vitamin K antagonists (VKA) an INR less than 1.5 is recommended prior to surgery, which can be achieved by pausing VKA intake or by administering vitamin K, prothrombin complex concentrate (PCC) or fresh frozen plasma (FFP). For the treatment with direct oral anticoagulants (DOAC) a plasma drug level of under 50 pg/mL is considered safe for surgery. If the plasma level can not be determined, a gap of 24 h between the last DOAC dose and surgery is recommended. The systemic administration of tranexamic acid can reduce overall blood loss and transfusion rates in anticoagulated patients with PFF. Surgical treatment of PFF should be performed within 24 h, as delayed surgery increases the risk for perioperative complications. This also applies to anticoagulated patients, when clinically appropriate. International and interdisciplinary guidelines are necessary to ensure early and appropriate treatment of anticoagulated elderly patients with PFF.

Association of direct oral anticoagulant and delayed bleeding with pharmacokinetics after endoscopic submucosal dissection

Pharmacokinetic parameters, such as drug plasma level at trough, time to maximum plasma concentration (Tmax), and coagulation factor Xa (FXa) activity generally predict factors for the anticoagulant effects of direct oral anticoagulants (DOACs). Although GI bleeding is a major adverse event after endoscopic submucosal dissection (ESD), little is known about the association between post-ESD bleeding in patients taking DOACs and the pharmacologic parameters. This study aimed to evaluate pharmacologic risk factors for post-ESD bleeding in patients taking DOACs. We prospectively evaluated the incidence of post-ESD bleeding in patients taking DOACs between April 2018 and May 2022 at 21 Japanese institutions and investigated the association with post-ESD bleeding and pharmacologic factors, including plasma concentration and FXa activity at trough and Tmax. The incidence of post-ESD bleeding was 12.8% (14 of 109; 95% confidence interval [CI], 7.2-20.6). Although plasma DOAC concentration and plasma level/dose ratio at trough and Tmax varied widely among individuals, a significant correlation with plasma concentration and FXa activity was observed (apixaban: correlation coefficient, -0.893; P< .001). On multivariate analysis, risk factors for post-ESD bleeding in patients taking DOACs were higher age (odds ratio [OR], 1.192; 95% CI, 1.020-1.392; P= .027) and high anticoagulant ability analyzed by FXa activity at trough and Tmax (OR, 6.056; 95% CI, 1.094-33.529; P= .039). The incidence of post-ESD bleeding in patients taking DOACs was high, especially in older patients and with high anticoagulant effects of DOACs. Measurement of pharmacokinetic parameters of DOACs may be useful in identifying patients at higher risk of post-ESD bleeding.

Abstract A134: Predicting activity of IMM-1-104 as single agent and in combination for patients with RAS or RAF mutant tumors

Abstract Introduction: Many tumors are addicted to MAPK pathway activation, including the &amp;gt;20% of human tumors with mutations in RAS or RAF1. IMM-1-104 is an oral once-daily treatment currently in Phase 1 in patients with RAS-mutant solid tumors [NCT05585320]. To date, drugs disrupting the MAPK pathway have done so chronically, leading to dose-limiting toxicities (DLTs) and poor response durability. In contrast, IMM-1-104 was designed to provide deep cyclic inhibition (DCI) of the MAPK pathway via a unique pharmacokinetic (PK) profile with high peak plasma drug levels and a near zero drug trough between doses. This promotes pulsatile inhibition of MEK, depriving tumors of sustained signaling of a critical oncogenic pathway while limiting toxicity and durability issues associated with chronic MEK inhibition. In Phase 1a dose escalation, no DLTs were observed, the plasma drug half-life was ~2-hours, and pharmacodynamic (PD) data were consistent with DCI. Phase 1b dose expansion is underway. Translational efforts are focused on identifying MAPK pathway addiction and sensitivity to IMM-1-104. Tumor models displaying patient-aligned genomic profiles against large patient databases such as AACR Project GENIE1 were tested in humanized 3D tumor growth assays (3D-TGA). Computational modeling based on response and in-house genomic data was used to inform identification of patient populations for IMM-1-104 monotherapy and potential combination opportunities. Experimental Procedures: Using cancer-specific, patient-aligned cell lines, IMM-1-104 activity was characterized in the 3D-TGA. Whole exome sequencing was performed to confirm alteration status, and a further subset subjected to RNA sequencing. Pharmacogenomic data were used to generate a model predictive of response to IMM-1-104 and identify biomarker-aligned patient subpopulations. Selected model predictions were then tested in subcutaneous tumor xenograft models in female BALB/c nude mice. Summary of New Data: Assessment of IMM-1-104 across &amp;gt;190 patient-aligned models demonstrated diverse responses across a wide range of MAPK-driven tumor types, including those with RAS or RAF mutations. In addition to RAS, these data suggested additional potential for IMM-1-104 in BRAF-mutant disease. Therefore, IMM-1-104 was tested alone and with encorafenib in the HT-29 colorectal BRAFV600E mutant xenograft model. Monotherapy with either encorafenib or IMM-1-104 displayed superior tumor growth inhibition to binimetinib. IMM-1-104 in combination with encorafenib drove deeper regressions and superior durability of response in a head-to-head in vivo comparison versus binimetinib plus encorafenib. Conclusions: We used an integrated platform of translational experiments and informatics to identify patient-aligned model systems, prioritize factors relevant for response to IMM-1-104’s unique DCI profile, and elucidate combination opportunities to potentially inform clinical development strategies. Citation Format: Praveen Nair, Sarah Kolitz, Jason Funt, Jan de Jong, Peter King, Amy Yamamura, Mai Johnson, Jenny Zhang, Kevin D Fowler, Anna Travesa, Amy Axel, Chris Walker, Scott Barrett, Benjamin J Zeskind, Brett Hall. Predicting activity of IMM-1-104 as single agent and in combination for patients with RAS or RAF mutant tumors [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2023 Oct 11-15; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2023;22(12 Suppl):Abstract nr A134.

Acquired and intrinsic resistance to vemurafenib in BRAFV600E -driven melanoma brain metastases.

BRAFV600 -mutated melanoma brain metastases (MBMs) are responsive to BRAF inhibitors, but responses are generally less durable than those of extracranial metastases. We tested the hypothesis that the drug efflux transporters P-glycoprotein (P-gp; ABCB1) and breast cancer resistance protein (BCRP; ABCG2) expressed at the blood-brain barrier (BBB) offer MBMs protection from therapy. We intracranially implanted A375 melanoma cells in wild-type (WT) and Abcb1a/b;Abcg2-/- mice, characterized the tumor BBB, analyzed drug levels in plasma and brain lesions after oral vemurafenib administration, and determined the efficacy against brain metastases and subcutaneous lesions. Although contrast-enhanced MRI demonstrated that the integrity of the BBB is disrupted in A375 MBMs, vemurafenib achieved greater antitumor efficacy against MBMs in Abcb1a/b;Abcg2-/- mice compared with WT mice. Concordantly, P-gp and BCRP are expressed in MBM-associated brain endothelium both in patients and in A375 xenografts and expression of these transporters limited vemurafenib penetration into A375 MBMs. Although initially responsive, A375 MBMs rapidly developed therapy resistance, even in Abcb1a/b;Abcg2-/- mice, and this was unrelated to pharmacokinetic or target inhibition issues. Taken together, we demonstrate that both intrinsic and acquired resistance can play a role in MBMs.

Real Word Data on Levels of Emicizumab and Their Correspondence with the Global Hemostatic Capacity and the Spontaneous Joint Bleeding in Patients on Emicizumab Prophylaxis

Introduction: Emicizumab has improved the management of patients with hemophilia A. However, few real-world data are available on drug plasma levels and their correspondence with global hemostatic capacity (GHC) and annualized spontaneous joint bleeding rate (ASJBR). Aims: Evaluation of the correlation between emicizumab plasma levels, GHC and ASJBR in patients on emicizumab prophylaxis. Methods: Multicenter, observational and cross-sectional study was performed in 4 Spanish hospitals. Emicizumab plasma levels and thrombin generation capacity (TGT, Genesia ®, Stago ®) of patients on emicizumab prophylaxis were determined in a central laboratory. Kinetics of clot formation was evaluated by rotational thromboelastometry (ROTEM ®, naTEM ® test, Werfen ®) in one center. Time on emicizumab prophylaxis and the number of spontaneous joint bleeds (SJB) was collected retrospectively using the clinical history. Results are expressed as median (25 th-75 th percentiles) or mean ± standard deviation depending on data distribution. A p-value &amp;lt; 0.05 was considered statistically significant. Results: Twenty-eight patients were included: 18 aged ≥12 years (age= 20.1 [14.7-38.9] years old) (group 1) and 10 patients aged &amp;lt;12 years (age= 6.1 [3.2-8.9] years old) (group 2) (p&amp;lt; 0.001). Globally, emicizumab levels were 46.3 ± 11.9 mcg/mL and similar between both groups: 45.2 ± 13.1 mcg/mL (group 1) and 45.9 ± 7.3 mcg/mL (group 2) (p=0.870) (Figure 1). No correlation was detected between emicizumab levels and TGT or ROTEM ®. Compared with healthy controls, patients presented lower values of thrombin generation: Peak (% compared to controls) = 41.4 (33.3-53.0) % and endogenous thrombin potential (ETP%) = 54.9 (38.9-73.4) %. However, on the contrary, ROTEM ® showed a similar procoagulant profile (example: CT and CT+CFT; p&amp;gt;0.05) or even higher (example: lower CFT values in patients; p= 0.023) compared to healthy subjects (Table 1). Throughout a follow-up period of 57.0 (32.3-102.3) weeks, none of the patients presented SJB (ASJBR =0). Conclusions: Emicizumab treatment provided excellent protection to patients throughout the study period. The wide interpatient variation on emicizumab plasma levels does not appear to have an impact on the development of SJB. TGT and ROTEM ® showed contradictory results: TGT describes lower thrombin generation capacity in patients compared to healthy controls, while ROTEM ® showed a similar or even higher procoagulant function in patients. Additional studies are required to explain these findings and their clinical significance.

Effect of Metformin on Plasma Exposure of Rifampicin, Isoniazid, and Pyrazinamide in Patients on Treatment for Pulmonary Tuberculosis.

To evaluate the effect of metformin on the plasma levels of rifampicin, isoniazid, and pyrazinamide in patients with drug-sensitive pulmonary tuberculosis being treated with first-line antituberculosis treatment (ATT) and to assess the influence of gene polymorphisms on the metabolic pathway of metformin and plasma levels of antitubercular drugs. Nondiabetic adults aged 18-60 years with pulmonary tuberculosis were randomized to either the standard ATT (ATT group) or ATT plus metformin (METRIF group) groups in a phase IIB clinical trial. An intensive pharmacokinetic study with blood collection at 0 hour (predosing), followed by 1, 2, 4, 6, 8, and 12 hours after dosing was conducted during the first month of treatment in a subset of 60 study participants after a minimum of 14 doses. Plasma concentrations of rifampicin, isoniazid, pyrazinamide, and metformin were measured by high-performance liquid chromatography using validated methods, and pharmacokinetic parameters and OCT1 and MATE1 gene polymorphisms were compared between the groups. Significant increases in the clearance of rifampicin, isoniazid, and pyrazinamide were observed in patients in the METRIF group (n = 29) compared with those in the ATT group (n = 31). The AA genotypes of the single-nucleotide polymorphism of rs2289669 ( MATE1 ) in the METRIF group showed a significantly decreased area under the concentration-time curve to the last observation point and increased clearance of rifampicin. Metformin altered rifampicin and isoniazid plasma concentrations in patients receiving antituberculosis treatment for pulmonary tuberculosis with little effect on sputum conversion at the end of treatment. Studies with larger sample sizes are needed to understand host drug-drug interactions.

1897. Therapeutic Drug Monitoring in CSF and Plasma in Tuberculous Meningitis:Correlation with Disease Outcome

Abstract Background Tuberculous meningitis (TBM) is a serious form of extra-pulmonary tuberculosis with significant morbidity and mortality. TBM patients are treated with pulmonary tuberculosis regimen, often requiring extension for 1 year or longer. Current study was designed to find any association of CSF and blood levels of anti-tubercular drugs with treatment response in patients with tuberculous meningitis using therapeutic drug monitoring. Pharmacokinetic Parameters of Rifampicin and Isoniazid in CSF and Plasma Methods A prospective observational study was conducted in a tertiary care institute in North India among clinic-radiologically and/or microbiologically diagnosed TBM patients. Plasma and CSF levels of anti TB drugs (rifampicin, isoniazid, pyrazinamide and ethambutol) were determined using Liquid Chromatography Mass Spectrometry technology at 1 week and 1 month (follow up) after initiating treatment. The primary outcome assessed was association of drug levels with treatment response. The secondary outcomes assessed were association of drug levels with treatment duration/alteration, patient demographic profile, comorbidities and adverse effects. Patients were followed-up till treatment completion. Results A total of 40 patients with TBM were recruited. All received daily weight-based doses of anti TB drugs. Low Cmax of INH and rifampicin in plasma were observed in 60.5% &amp; 42.1% of observations respectively. In CSF, low Cmax of INH and rifampicin were observed in 77.6% &amp; 82.9% of observations respectively. The concentrations of INH (4 hours after drug intake) during follow up were significantly lower among patients with poor response, at 1 month (p=0.008) &amp; 6 months (p=0.009). Similarly, low Cmax &amp; CSF levels of INH at follow up sampling were significantly associated with poor response at 6 months of therapy (p= 0.022 &amp; 0.042 respectively). Conclusion Low plasma and CSF concentrations of isoniazid were associated with a poor response to treatment in patients with TBM. Therapeutic drug monitoring can guide dose modification of ATT to achieve target concentrations in patients with TBM and facilitate optimal treatment outcomes. Higher dose INH can be considered in TBM treatment regimen for better outcome. Disclosures All Authors: No reported disclosures

Plasma levels of direct oral anticoagulants in non-valvular atrial fibrillation patients at the time of acute cardioembolic or bleeding events

Abstract Background Direct oral anticoagulants (DOACs) are approved for preventing cardioembolic events in patients with non-valvular atrial fibrillation (NVAF) (1). Unlike Heparin and vitamin K antagonists, DOACs are commonly used without the need for clotting time monitoring, which results in limited data on the correlation between plasma levels and adverse events (2). Objective This study aimed to evaluate, in a real-world cohort of NVAF patients, the relationship between the occurrence of acute cardioembolic or major bleeding events and the plasma levels of DOACs measured at the time of the events. Methods and Results This study included 400 NVAF patients on DOAC therapy from the INSIghT registry who underwent plasma drug level testing at the time of an adverse event (116 cases) or during an elective hospitalization or outpatient visit (284 controls). Out of 116 cases, 74 experienced a cardioembolic event while 42 had a major bleeding. Patients with cardioembolic events presented low (i.e., in the first and second quartiles) DOAC plasma levels (50 vs. 24, p&amp;lt;0.01), while patients with major bleeding events had high (i.e., in the third and fourth quartiles) DOAC plasma levels (25 vs. 14, p&amp;lt;0.01). Conclusions This study highlights the possible association between plasma levels of DOACs and the risk of adverse events, but further research is needed to fully understand the potential benefits DOAC monitoring and individualized dosing.Fig. 1Fig. 2

Transdermal Drug Delivery Systems: A Focused Review of the Physical Methods of Permeation Enhancement.

The skin is the body's largest organ and serves as a site of administration for various medications. Transdermal drug delivery systems have several advantages over traditional delivery systems. It has both local and systemic therapeutic properties. Controlled plasma drug levels, reduced dosing frequency, and avoidance of hepatic first-pass metabolism are just a few of these systems' advantages. To achieve maximum efficacy, it is critical to understand the kinetics, physiochemical properties of the drug moiety, and drug transport route. This manuscript focused on the principles of various physical means to facilitate transdermal drug delivery. Some examples are iontophoresis, electrophoresis, photomechanical waves, ultrasound, needleless injections, and microneedles. Mechanical, chemical, magnetic, and electrical energy are all used in physical methods. A major advantage of physical methods is their capability to abbreviate pain, which can be used for effective disease management. Further investigation should be carried out at the clinical level to understand these methods for effective drug delivery.

Dermal effects and pharmacokinetic evaluation of the lidocaine/prilocaine cream in healthy Chinese volunteers

BackgroundEMLA cream is a local anesthetic. The pharmacokinetics and dermal effects of a topical anesthetic formulation has not been evaluated in healthy Chinese volunteers.Materials and methodsThe Pharmacokinetics of the lidocaine/prilocaine test (T) or reference (R, EMLA) cream were evaluated in a fasting, single-dose, two-period crossover bioequivalent study conducted in 40 healthy Chinese volunteers. Meanwhile, the dermal effects including blanching, erythema, temperature sensation, edema, and skin rash were also evaluated during the study.ResultsAfter applied 15 g of the cream for 4 h to a 100 cm2 area under plastic occlusive film on the skin of the thigh of healthy volunteers, the results of the pharmacokinetic study showed that the active components absorbed in skin from topical products was relatively low compared with most system absorption drugs. After the removal of the residual anesthetic cream, there was a vascular biphasic response with initial transient blanching which reaches a peak at 4.5 h and later more persisting period erythema. The change of temperature sensory sensitivity reached the peak value at 4.5-6 h.There was no statistically significant difference of the changes after application the lidocaine/prilocaine T or R cream in subjects. In general, the lidocaine/prilocaine T or R cream was well tolerated.ConclusionThe method described a model for investigations of pharmacokinetics and pharmacodynamics of topical lidocaine/prilocaine cream. Except the plasma drug level indicator, these pharmacodynamics data should also be evaluated in the anesthetic transdermal pharmacokinetics study.Clinical Trial RegistrationCTR20211544; registered in http://www.chinadrugtrials.org.cn/ at September 2021.

Distribution pattern of UGT1A6 and UGT2B7 gene polymorphism and its impact on the pharmacokinetics of valproic acid and carbamazepine: Prospective genetic association study conducted in Pakistani patients with epilepsy

BackgroundEthnic variation is one of the important factors in clinical practice that may affect the pharmacokinetics of drugs. The present study aims to determine the distribution pattern of UGT1A6 and UGT2B7 gene polymorphism and its possible impact on the metabolism of valproic acid (VPA) and carbamazepine (CBZ) in patients with epilepsy from Khyber Pakhtunkhwa region of Pakistan. Methods: After the enrollment of targeted patients, blood was collected for genotype analysis through Sanger sequencing. Plasma concentrations of VPA and CBZ were determined by reversed-phase high-performance liquid chromatography (HPLC) at the follow-up visit of third month from the initiation of therapy. The drug plasma levels were correlated with different genotypes of UGT1A6 and UGT2B7 to determine the impact of genetic polymorphism on the drug metabolism. Results: Of the total 178 epileptic patients, 120 subjects were prescribed VPA monotherapy while 58 subjects were given CBZ monotherapy. The mean age of the subjects was recorded as 26.1 ± 13.5 years with a predominance of the male gender. Generalized tonic-clonic (GTC) was the most prevalent type of seizure (82%) followed by partial seizure. Genotype analysis revealed that the frequency of homozygous and heterozygous variants of the targeted UGT genes were exceptionally high in the Khyber Pakhtunkhwa population compared to the ethnic groups of other countries. In UGT1A6-A552C and UGT1A6-A541G, AC and AG were the most prevalent genotypes with respective frequencies of 43.2% and 41.1% whereas, in UGT2B7-T161C and UGT2B7-G211T, TC and GG were the most prevalent genotypes with respective frequencies of 42.7% and 99.4%. In the VPA-treated group, the homozygous and heterozygous variants of UGT1A6-A552C and UGT1A6-A541G were significantly associated with lower drug plasma concentrations (p < 0.05). However, none of the genotypes of UGT2B7-T161C revealed any significant association with VPA plasma concentration (p greater than 0.05). In the CBZ-treated group, UGT gene polymorphisms were not recognized to cause alteration in the drug plasma concentrations (p greater than 0.05). Conclusion: The genetic polymorphisms of UGT1A6, but not UGT2B7 significantly affected the plasma levels of valproic acid. The chosen SNPs did not reveal a role in determining the plasma levels of carbamazepine.

A Critical Overview of Enzyme-Based Electrochemical Biosensors for L-Dopa Detection in Biological Samples

L-Dopa is an intermediate amino acid in the biosynthesis of endogenous catecholamines, such as dopamine. It is currently considered to be the optimal dopaminergic treatment for Parkinson’s disease, a neurodegenerative disorder affecting around 1% of the population. In an advanced stage of the disease, complications such as dyskinesia and psychosis are caused by fluctuations in plasma drug levels. Real-time monitoring of L-Dopa levels would be advantageous for properly adjusting drug dosing, thus improving therapeutic efficacy. Electrochemical methods have advantages such as easy-to-use instrumentation, fast response time, and high sensitivity, and are suitable for miniaturization, enabling the fabrication of implantable or wearable devices. This review reports on research papers of the past 20 years (2003–2023) dealing with enzyme-based biosensors for the electrochemical detection of L-Dopa in biological samples. Specifically, amperometric and voltammetric biosensors, whose output signal is a measurable current, are discussed. The approach adopted includes an initial study of the steps required to assemble the devices, i.e., electrode modification and enzyme immobilization. Then, all issues related to their analytical performance in terms of sensitivity, selectivity, and capability to analyze real samples are critically discussed. The paper aims to provide an assessment of recent developments while highlighting limitations such as poor selectivity and long-term stability, and the laborious and time-consuming fabrication protocol that needs to be addressed from the perspective of the integrated clinical management of Parkinson’s disease.

Long-acting lenacapavir acts as an effective preexposure prophylaxis in a rectal SHIV challenge macaque model.

Long-acting antiretroviral agents for preexposure prophylaxis (PrEP) represent a promising new alternative to daily oral regimens for HIV prevention. Lenacapavir (LEN) is a first-in-class long-acting capsid inhibitor approved for the treatment of HIV-1 infection. Here, we assessed the efficacy of LEN for PrEP using a single high-dose simian-human immunodeficiency virus (SHIV) rectal challenge macaque model. In vitro, LEN showed potent antiviral activity against SHIV, as it did for HIV-1. In macaques, a single subcutaneous administration of LEN demonstrated dose proportional increases in and durability of drug plasma levels. A high-dose SHIV inoculum for the PrEP efficacy evaluation was identified via virus titration in untreated macaques. LEN-treated macaques were challenged with high-dose SHIV 7 weeks after drug administration, and the majority remained protected from infection, as confirmed by plasma PCR, cell-associated proviral DNA, and serology testing. Complete protection and superiority to the untreated group was observed among animals whose LEN plasma exposure exceeded its model-adjusted clinical efficacy target at the time of challenge. All infected animals had subprotective LEN concentrations and showed no emergent resistance. These data demonstrate effective SHIV prophylaxis in a stringent macaque model at clinically relevant LEN exposures and support the clinical evaluation of LEN for HIV PrEP in humans.

Microneedles and Their Application in Transdermal Delivery of Antihypertensive Drugs-A Review.

One of the most cutting-edge, effective, and least invasive pharmaceutical innovations is the utilization of microneedles (MNs) for drug delivery, patient monitoring, diagnostics, medicine or vaccine delivery, and other medical procedures (e.g., intradermal vaccination, allergy testing, dermatology, and blood sampling). The MN-based system offers many advantages, such as minimal cost, high medical effectiveness, comparatively good safety, and painless drug application. Drug delivery through MNs can possibly be viewed as a viable instrument for various macromolecules (e.g., proteins, peptides, and nucleic acids) that are not efficiently administered through traditional approaches. This review article provides an overview of MN-based research in the transdermal delivery of hypertensive drugs. The critical attributes of microneedles are discussed, including the mechanism of drug release, pharmacokinetics, fabrication techniques, therapeutic applications, and upcoming challenges. Furthermore, the therapeutic perspective and improved bioavailability of hypertensive drugs that are poorly aqueous-soluble are also discussed. This focused review provides an overview of reported studies and the recent progress of MN-based delivery of hypertensive drugs, paving the way for future pharmaceutical uses. As MN-based drug administration bypasses first-pass metabolism and the high variability in drug plasma levels, it has grown significantly more important for systemic therapy. In conclusion, MN-based drug delivery of hypertensive drugs for increasing bioavailability and patient compliance could support a new trend of hypertensive drug delivery and provide an alternative option, overcoming the restrictions of the current dosage forms.

In vitro identification of decreased function phenotype ABCG2 variants

Reduced activity of efflux transporter ABCG2, caused e.g., by inhibition or decreased function genetic variants, can increase drug absorption and plasma levels. ABCG2 has one clinically significant single nucleotide variant Q141K (c.421C>A), which leads to decreased protein levels and transport activity. In addition to Q141K, ABCG2 has over 500 rare (<1% minor allele frequency) nonsynonymous variants, but their functionality remains unknown. We studied the transport activity and abundance of 30 rare ABCG2 variants. The variants were transiently expressed in HEK293 cells. Transport activity and protein abundance were measured from inside-out crude membrane vesicles. Results were normalised to the reference ABCG2, while Q141K was used to categorise variants into decreased and normal function phenotypes based on their apparent transport activity. Fourteen variants (G80E, D128V, T434M, Q437R, C438R, C438W, C438Y, L479S, P480L, S486N, T512N, S519P, G553D and K647E) had similar or lower apparent transport activity than Q141K and thus were categorised as having a decreased function phenotype. Protein abundance could not explain all of the observed changes in transport activity: Only six variants (D128V, Q437R, C438R, S519P, G553D, and K647E) had similar or lower abundance compared to Q141K. The decreased function variants may increase systemic drug exposure and therefore cause interindividual variability in pharmacokinetics. In the future, in vitro phenotype classification may help to design personalised drug treatments.

Pharmacokinetic Drug-Drug Interactions: A Systematic Review of the Cytochrome P450 (CYP) Isoenzyme 3A4

The cytochrome P450 (CYP) isoenzyme 3A4 or CYP3A4 is a major drug-metabolizing enzyme that has the potential to cause pharmacokinetic drug-drug interactions. Primary research studies have demonstrated CYP3A4-mediated drug-drug interactions through a variety of mechanisms. However, there has been no review during the last 10 years of pharmacokinetic drug-drug interactions mediated by CYP3A4 isoenzymes. It is necessary to systematically review the pharmacokinetic drug-drug interactions mediated by CYP3A4. Source review of articles were retrieved from the PubMed and Scopus databases. The preparation of keywords through the population, intervention, comparison, and outcomes (PICO) method written based on the Boolean operator. Reporting the results of the paper search is presented in the Prisma version 1 2020 flowchart. The risk of bias assessment used COHORT tools and Systematic Review Center for Laboratory Animal Experimentation (SYRCLE) tools. Data was analyzed narratively. Pharmacokinetic drug interactions are mediated by CYP3A4 through the mechanism of induction, activation, inhibition, and inactivation. Induction or activation of CYP3A4 can cause an increase in CYP3A4 expression, so that the drug is metabolized more quickly and has the potential to lose drug efficacy. Inhibition and inactivation of CYP3A4 causes plasma drug levels to increase and drug elimination time to last longer. CYP3A4 plays a major role in the bioactivation of drugs that cause hepatotoxicity through the formation of reactive metabolites. The use of drugs needs to be monitored to avoid pharmacokinetic drug interactions.

Accelerated reactive dissolution model of drug release from long-acting injectable formulations

Long-acting injectable formulations represent a rapidly emerging category of drug delivery systems that offer several advantages compared to orally administered medicines. Rather than having to frequently swallow tablets, the medication is administered to the patient by intramuscular or subcutaneous injection of a nanoparticle suspension that forms a local depot from which the drug is steadily released over a period of several weeks or months. The benefits of this approach include improved medication compliance, reduced fluctuations of drug plasma level, or the suppression of gastrointestinal tract irritation. The mechanism of drug release from injectable depot systems is complex, and there is a lack of models that would enable quantitative parametrisation of the process. In this work, an experimental and computational study of drug release from a long-acting injectable depot system is reported. A population balance model of prodrug dissolution from asuspension with specific particle size distribution has been coupled with the kinetics of prodrug hydrolysis to its parent drug and validated using in vitro experimental data obtained from an accelerated reactive dissolution test. Using the developed model, it is possible to predict the sensitivity of drug release profiles to the initial concentration and particle size distribution of the prodrug suspension, and subsequently simulate various drug dosing scenarios. Parametric analysis of the system has identified the boundaries of reaction- and dissolution-limited drug release regimes, and the conditions for the existence of a quasi-steady state. This knowledge is crucial for the rational design of drug formulations in terms of particle size distribution, concentration and intended duration of drug release.

Recent Updates and Advancement of Transdermal Drug Delivery System

Tranderrmal drug delivery system is topically used drug administration’s which are mainly used in the form patch and the transdermal patch are applied on the skin. TDDS have better drug absorption, good bioavailability and the drug delivered through the skin in a systemic circulation by controlled drug delivery system. Today about 74% of drug are taken orally and that are less side effect, the drug are transported through the viable epidermis to dermis tissue of skin for the local therapeutic effect into the systemic circulation, TDDS avoids the first- pass metabolism , increased therapeutic effect and maintained the plasma drug level. In pharmaceutical industries have many new advancement of technology which modified all resources in TDDS, the drug used as a controlled drug delivery system but now days we used novel drug delivery system which is painless method of drug administration . The scientific development of transdermal patches were comes in 1970s and the first patches were approved in 1979 by FDA for the treatment of motion sickness. Now days, there are many numbers of patches exist in market such as fentanyl, nicotine, clonidine, nitroglycerine, oxybutinin, testosterone, lidnocaine and scopolamine. Along with, the transdermal drug delivery system (TDDS) represents many approaches. In this overview, we describe the different types of TDDS methods available and critically discuss their specific strengths and weaknesses, characterization methods, and the potential of each method. Advances in research on these alternative methods have demonstrated the high performance inherent in the TDDS, which are expected to find application in a wide range of applied.