Topical Aprepitant (HT-001): A Novel Therapy for Epidermal Growth Factor Receptor Inhibitor-Associated Papulopustular Eruptions.

Papulopustular eruptions are the most common dermatologic side effect of epidermal growth factor receptor inhibitor (EGFRI) therapy. Topical corticosteroids and oral tetracyclines are frequently used to manage these eruptions, though these treatments are limited by their adverse effects and efficacy. Results from preclinical studies suggest a role for topical aprepitant (HT-001) in the treatment of EGFRI-induced skin toxicities. Herein a case of EGFRI-induced papulopustular eruption with rapid treatment response to topical aprepitant (HT-001) 2% cream is described and the literature reviewed. J Drugs Dermatol. 2024;23(9):e173-e174. doi:10.36849/JDD.8617.

Aprepitant's roles in abating seizures, behavioral, and cognitive deficits in mice model of epilepsy.

BACKGROUND: Aprepitant (APR), a neurokinin 1 receptor antagonist, is an approved drug for treating chemotherapy-induced nausea and vomiting. OBJECTIVES: Investigate the beneficial roles of APR alone or in combination with sodium valproate (VPA) against lithium pilocarpine [li-pilo]-induced seizures, behavioral changes, and cognitive deficits. METHODS: Thirty male mice were divided into five groups, each containing 6. "Vehicle Group I," "Control Group II "li-pilo, " Valproate (VPA) group III (400 mg/kg/i.p.), "APR group IV, " and "Combination Group V." Videos of mice were recorded, and they were watched for episodes of spontaneous recurring seizures (SRS). Behavioral Tests were performed. At the end of the study, animal brains were taken for biochemical assays and gene expression studies. RESULTS: APR partially protected against SRS with partial restoration of average behavioral and standard cognitive skills associated with a significant increase in brain SOD activity and a significant decrease in MDA, IL-1ß, NF-КB, and SP-3 levels in relation to the control group. Interestingly, a combination of APR with VPA in epileptic mice showed complete protection against li-pilo-induced behavioral changes and cognitive deficits, a significant increase in brain SOD activity, and a considerable decrease in MDA, IL-1ß, NF-ΚB, and SP levels to normal. CONCLUSION: Using APR as an adjuvant to VPA is more effective in protecting against li-pilo-induced seizures, behavioral changes, and cognitive deficits due to its antioxidant, anti-inflammatory, and NK1 antagonist effects than using APR alone as drug therapy.

Neurokinin receptor antagonists as potential nonhormone treatments for vasomotor symptoms.

Managing menopause symptoms is challenging for women unable or unwilling to take hormone therapy. All nonhormone options thus far have shown less overall efficacy compared with hormone therapy and significant adverse events that limit their use. New science has identified the source of vasomotor symptoms, achieving relief of these bothersome symptoms by directly targeting the neurokinin 3 receptor and its related pathways. This Practice Pearl reviews the clinical data available on neurokinin receptor antagonists.

Impact of Physiological Characteristics on Chylomicron Pathway-Mediated Absorption of Nanocrystals in the Pediatric Population.

Nanocrystals exhibit significant advantages in improving the oral bioavailability of poorly soluble drugs. However, the complicated absorption properties of nanocrystals and the differences in physiological characteristics between children and adults limit pediatric applications of nanocrystals. To elucidate the absorption differences and the underlying mechanisms between children and adults, the pharmacokinetics and tissue distribution of aprepitant crystals with different particle sizes (NC200, NC500, and MC2.5) in rats and mice at different ages were studied, and their absorption mechanisms were investigated in Caco-2 cells, mice, and rats. It was found that childhood animals demonstrated higher bioavailability compared with adolescent and adult animals, which was related to higher bile salt concentration and accelerated drug dissolution in the intestine of childhood animals. The majority of nanocrystals were dissolved and formed micelles under the influence of bile salts. Compared with intact nanocrystals, the bile salt micelle-associated aprepitant was absorbed through the chylomicron pathway, wherein Apo B assisted in the reassembling of the aprepitant micelles after endocytosis. Higher bile salt concentration and Apo B expression in the intestines of childhood animals are both responsible for the higher chylomicron transport pathways. Elucidation of the chylomicron pathway in the varied absorption of nanocrystals among children, adolescents, and adults provides strong theoretical guidance for promoting the rational and safe use of nanocrystals in pediatric populations.

Olanzapine as Antiemetic Prophylaxis in Moderately Emetogenic Chemotherapy: A Phase 3 Randomized Clinical Trial.

Importance: The role of olanzapine has not been adequately evaluated in moderately emetogenic chemotherapy (MEC) regimens with or without neurokinin-1 receptor antagonists. Objective: To evaluate whether addition of olanzapine to an MEC regimen reduces nausea, vomiting, and use of nausea rescue medications among patients with solid malignant tumors. Design, Setting, and Participants: This multicenter, open-label phase 3 randomized clinical trial included patients aged 18 years or older with solid malignant tumors who were receiving oxaliplatin-, carboplatin-, or irinotecan-based chemotherapy. The trial was conducted at 3 institutes in India from March 26, 2019, to August 26, 2023; the final cutoff date for analysis was September 10, 2023. Exposure: Patients were randomized 1:1 to dexamethasone, aprepitant, and palonosetron with olanzapine (experimental group) or without olanzapine (observation group). The experimental group received 10 mg of olanzapine orally once at night on days 1 through 3 of the chemotherapy regimen. Main Outcomes and Measures: The primary end point was complete response (CR), defined as the proportion of patients with no vomiting, no significant nausea (scored as <5 on a visual analog scale of 1 to 100), and no use of rescue medications for nausea. Secondary end points included the proportion of patients experiencing nausea and chemotherapy-induced nausea and vomiting (CINV), receiving rescue medications, and experiencing adverse events. Results: A total of 560 patients (259 [64%] male; median age, 51 years [range, 19-80 years]) were randomized. The analysis included 544 patients with evaluable data (274 assigned to olanzapine and 270 to observation). Baseline characteristics were evenly matched between the 2 groups. The proportion of patients with CR was significantly greater in the group with (248 [91%]) than without (222 [82%]) olanzapine in the overall 120-hour treatment period (P = .005). Likewise, there were significant differences between the olanzapine and observation groups for nausea control (264 [96%] vs 234 [87%]; P < .001) and CINV (262 [96%] vs 245 [91%]; P = .02) during the overall assessment period, and the proportion of patients receiving rescue medications significantly increased in the observation group (30 [11%]) compared with the olanzapine group (11 [4%]) (P = .001). Grade 1 somnolence was reported by 27 patients (10%) following administration of chemotherapy and olanzapine and by no patients in the observation group. Conclusions and Relevance: In this randomized clinical trial, the addition of olanzapine significantly improved CR rates as well as nausea and vomiting prevention rates in chemotherapy-naive patients who were receiving MEC regimens containing oxaliplatin, carboplatin, or irinotecan. These findings suggest that use of olanzapine should be considered as one of the standards of care in these chemotherapy regimens. Trial Registration: Clinical Trials Registry-India (CTRI) Identifier: CTRI/2018/12/016643.

Comparing Injection Site Reactions of Aprepitant and Fosaprepitant in Gynecologic Cancer Chemotherapy.

BACKGROUND/AIM: The frequency rate of injection site reactions (ISR) due to fosaprepitant meglumine (Fos APR) has been shown to vary depending on the types of combined anticancer drug. This study aimed to elucidate the impact of Fos APR on ISR in patients receiving paclitaxel and carboplatin, with and without bevacizumab therapy (TC±Bev). PATIENTS AND METHODS: This study focused on patients with gynecologic cancer (n=93) who received TC±Bev administration at Fujita Health University Hospital from March 2016 to February 2020, and monitored up to six cycles. The patients were randomly assigned to the Fos APR group (n=47) and the Aprepitant (APR) group (n=46). Using Visual Infusion Phlebitis (VIP) scores, ISR was evaluated by comparing the VIP scores of all cycles using a linear mixed model. The risk factors that contribute to the occurrence of vascular pain throughout all cycles were also examined. RESULTS: The VIP scores of all cycles showed a near significant intergroup difference (p=0.071). Factors that affected the development of vascular pain included Fos APR and age (p=0.027 and 0.049, respectively). Regarding age, patients aged <65 years had a higher risk. Four patients underwent a switch from the originally assigned neurokinin-1 receptor antagonist; in all of these cases, Fos APR was changed to APR for vascular pain. CONCLUSION: Fos APR may increase the risk for ISR associated with TC±Bev therapy for gynecological cancer.

Enhanced anti-angiogenic effects of aprepitant-loaded nanoparticles in human umbilical vein endothelial cells.

Recent advancements in cancer therapy have led to the development of novel nanoparticle-based drug delivery systems aimed at enhancing the efficacy of chemotherapeutic agents. This study focuses on evaluating aprepitant-loaded PLGA and Eudragit RS 100 nanoparticles for their potential antiangiogenic effects. Characterization studies revealed that aprepitant-loaded nanoparticles exhibited particle sizes ranging from 208.50 to 238.67 nm, with monodisperse distributions (PDI < 0.7) and stable zeta potentials (between - 5.0 and - 15.0 mV). Encapsulation efficiencies exceeding 99% were achieved, highlighting the efficacy of PLGA and Eudragit RS 100 as carriers for aprepitant. Cellular uptake studies demonstrated enhanced internalization of aprepitant-loaded nanoparticles by HUVEC cells compared to free aprepitant, as confirmed by fluorescence microscopy. Furthermore, cytotoxicity assays revealed significant dose-dependent effects of aprepitant-loaded nanoparticles on HUVEC cell viability, with IC50 values at 24 h of 11.9 µg/mL for Eudragit RS 100 and 94.3 µg/mL for PLGA formulations. Importantly, these nanoparticles effectively inhibited HUVEC cell migration and invasion induced by M2c supernatant, as evidenced by real-time cell analysis and gene expression studies. Moreover, aprepitant-loaded nanoparticles downregulated VEGFA and VEGFB gene expressions and reduced VEGFR-2 protein levels in HUVEC cells, highlighting their potential as antiangiogenic agents. Overall, this research underscores the promise of nanoparticle-based aprepitant formulations in targeted cancer therapy, offering enhanced therapeutic outcomes through improved drug delivery and efficacy against angiogenesis.

Efficacy of aprepitant for refractory pruritus in patients with epidermolysis bullosa and atopic dermatitis: A retrospective study.

INTRODUCTION: At a single-center pediatric hospital, the neurokinin-1 receptor antagonist aprepitant was used to treat refractory pruritus in epidermolysis bullosa (EB) and atopic dermatitis (AD). METHODS: Thirty-seven patients were included (24 EB patients, 13 AD patients), ages 10 months to 37 years. RESULTS: 58% (14/24) of patients with EB and 85% (11/13) of patients with AD reported aprepitant was effective in decreasing their pruritus, with age-related differences in efficacy observed in EB patients, and access to the medication by insurance denial or availability of the drug as a barrier to use. CONCLUSIONS: Aprepitant shows promise in controlling refractory pruritus in pediatric EB and AD patients and deserves further study.

Health-Related Quality of Life and Economic Analysis of Olanzapine Versus Aprepitant in Preventing Chemotherapy-Induced Nausea and Vomiting in Patients Receiving Highly Emetogenic Chemotherapy in Malaysia.

OBJECTIVES: Olanzapine has been shown to be effective in preventing chemotherapy-induced nausea and vomiting (CINV) after highly emetogenic chemotherapy (HEC); however, there is limited work on the impact of CINV on health-related quality of life (HRQoL) and the comparative cost-effectiveness of CINV prophylaxis in the Malaysian context. Therefore, this study was conducted to determine the HRQoL using EQ-5D-5L and the cost-effectiveness of olanzapine compared with aprepitant for CINV prophylaxis in Malaysia using data from a local study. METHODS: Fifty-nine chemo-naive patients receiving either olanzapine or aprepitant were randomly recruited and completed the EQ-5D-5L before and day 5 after HEC. HRQoL utility scores were analyzed according to the Malaysian valuation set. The economic evaluation was conducted from a healthcare payer perspective with a 5-day time horizon. Quality-adjusted life days (QALD) and the rate of successfully treated patients were used to measure health effects. The incremental cost-effectiveness ratio is assessed as the mean difference between groups' costs per mean difference in health effects. A one-way sensitivity analysis was performed to assess variations that might affect outcomes. RESULTS: Aprepitant and olanzapine arms' patients had comparable baseline mean HRQoL utility scores of 0.920 (SD = 0.097) and 0.930 (SD = 0.117), respectively; however, on day 5, a significant difference (P value = .006) was observed with mean score of 0.778 (SD = 0.168) for aprepitant and 0.889 (SD = 0.133) for olanzapine. The cost per successfully treated patient in the aprepitant arm was 60 times greater than in the olanzapine arm (Malaysian Ringgit [MYR] 927 vs MYR 14.83). Likewise, the cost per QALD gain in the aprepitant arm was 36 times higher than in the olanzapine arm (MYR 57.05 vs MYR 1.57). Incremental cost-effectiveness ratio of MYR -937.00 (USD -200.98) per successfully treated patient and MYR -391.84 (USD -85.43) per QALD gained for olanzapine compared with the aprepitant-based regimen. CONCLUSIONS: An olanzapine-based regimen is a cost-effective therapeutic substitution in patients receiving HEC in Malaysia.

The Efficacy of Aprepitant in Preventing Post-bariatric Surgery Nausea and Vomiting: Evidence from Clinical Trials.

INTRODUCTION: This study aims to evaluate the effectiveness of aprepitant in preventing postoperative nausea and vomiting (PONV) following metabolic bariatric surgery (MBS). METHODS: Clinical trials meeting the inclusion criteria were identified through searches of PubMed, Embase, and the Cochrane Library databases, as well as clinical trials registered at clinicaltrials. gov. These trials compared aprepitant with the control or placebo groups among patients who underwent MBS. Meta-analysis was performed using StataSE 17.0 software to calculate the pooled risk ratio (RR) and its 95% confidence interval (CI) to assess the effectiveness of aprepitant in preventing PONV following MBS. RESULTS: A total of five articles comprising six studies including 929 patients undergoing MBS were included. Meta-analysis revealed a significant reduction in the incidence of PONV among patients receiving aprepitant (pooled RR = 0.51, 95% CI: 0.38-0.68, P < 0.05). Subgroup analysis indicated that aprepitant effectively reduced PONV incidence at 0, 6, and 12 h postoperatively in patients with MBS, but did not decrease PONV occurrence at 24 and 48 h postoperatively. CONCLUSION: Aprepitant demonstrated significant clinical efficacy in preventing PONV following MBS, effectively reducing patient discomfort, and improving postoperative recovery. Therefore, aprepitant should be considered a preventive measure in patients undergoing MBS to enhance patient satisfaction and recovery rates. Additionally, to maintain an effective drug concentration, aprepitant should be administered within the first 24 h postoperatively. PROSPERO REGISTRATION: CRD 42024528154.

Evaluation of Efficacy of Adding Aprepitant to Palonosetron and Dexamethasone in Carboplatin and Etoposide Therapy.

Although carboplatin (CBDCA) is classified as a moderately emetogenic agent, the majority of guidelines recommend the use of a neurokinin-1 receptor antagonist in addition to a 5-hydroxytryptamine type 3 receptor antagonist with dexamethasone (DEX) for CBDCA-containing chemotherapy because of its higher emetogenic risk. However, the additional efficacy of aprepitant (APR) in CBDCA-containing treatment remains controversial, and data on multiple-day treatments are limited. Etoposide (ETP) was administered on days 1-3 in the CBDCA + ETP regimen, and it is important to evaluate suitable antiemetic therapy for the regimen. Therefore, we evaluated the efficacy of additional APR in CBDCA + ETP. Patients were divided into two groups and retrospectively evaluated. One was the control group, which was prophylactically administered palonosetron (PALO) and DEX, and the other was the APR group, which received APR orally with PALO and DEX. The primary endpoint was complete response (CR) between the groups. The overall CR rates were 75.0 and 76.4% in the control and APR groups, respectively, with no significant difference (p = 1.00). In the acute phase, it was 88.9 and 97.2%, respectively, and 86.1 and 79.2% in the delayed phase, respectively, without significant differences (p = 0.10 and 0.38, respectively). The incidence and severity of nausea, vomiting, and anorexia were not significantly different between the two groups in the acute and delayed phases. Our findings suggest that combining APR with PALO and DEX does not improve the CR rate in CBDCA + ETP therapy.

Olanzapine Plus Triple Antiemetic Therapy for the Prevention of Carboplatin-Induced Nausea and Vomiting: A Randomized, Double-Blind, Placebo-Controlled Phase III Trial.

PURPOSE: We evaluated the efficacy and safety of antiemetic therapy with olanzapine, a neurokinin-1 receptor antagonist (RA), a 5-hydroxytryptamine-3 (5-HT3) RA, and dexamethasone for preventing chemotherapy-induced nausea and vomiting in patients receiving carboplatin-containing chemotherapy. PATIENTS AND METHODS: Chemotherapy-naïve patients scheduled to receive carboplatin (AUC ≥5) were randomly assigned to receive either olanzapine 5 mg once daily (olanzapine group) or placebo (placebo group) in combination with aprepitant, a 5-HT3 RA, and dexamethasone. The primary end point was the complete response (CR; no vomiting and no rescue therapy) rate in the overall phase (0-120 hours). Secondary end points included the proportion of patients free of nausea and safety. RESULTS: In total, 355 patients (78.6% male, median age 72 years, 100% thoracic cancer), including 175 and 180 patients in the olanzapine and placebo groups, respectively, were evaluated. The overall CR rate was 86.9% in the olanzapine group versus 80.6% in the placebo group. The intergroup difference in the overall CR rate was 6.3% (95% CI, -1.3 to 13.9). The proportions of patients free of chemotherapy-induced nausea in the overall (88.6% in the olanzapine group v 75.0% in the placebo group) and delayed (89.7% v 75.6%, respectively) phases were significantly higher in the olanzapine group than in the placebo group (both P < .001). Somnolence was observed in 43 (24.6%) and 41 (22.9%) patients in the olanzapine and placebo groups, respectively, and no events were grade ≥3 in severity. CONCLUSION: The addition of olanzapine was not associated with a significant increase in the overall CR rate. Regarding the prevention of nausea, adding olanzapine provided better control in patients receiving carboplatin-containing chemotherapy, which needs further exploration.

PVP/aprepitant microcapsules produced by supercritical antisolvent process.

The supercritical antisolvent (SAS) process was a green alternative to improve the low bioavailability of insoluble drugs. However, it is difficult for SAS process to industrialize with limited production capacity. A coaxial annular nozzle was used to prepare the microcapsules of aprepitant (APR) and polyvinylpyrrolidone (PVP) by SAS with N, N-Dimethylformamide (DMF) as solvent. Meanwhile, the effects of polymer/drug ratio, operating pressure, operating temperature and overall concentration on particles morphology, mean particle diameter and size distribution were analyzed. Microcapsules with mean diameters ranging from 2.04 µm and 9.84 µm were successfully produced. The morphology, particle size, thermal behavior, crystallinity, drug content, drug dissolution and residual amount of DMF of samples were analyzed. The results revealed that the APR drug dissolution of the microcapsules by SAS process was faster than the unprocessed APR. Furthermore, the drug powder collected every hour is in the kilogram level, verifying the possibility to scale up the production of pharmaceuticals employing the SAS process from an industrial point of view.

Aprepitant Alleviates Poststroke Pneumonia in a Mouse Model of Middle Cerebral Artery Occlusion.

Elevated substance P can be utilized to predict early mortality during the first week of cerebral infarction. Whether aprepitant, a substance P receptor blocker could be utilized to alleviate poststroke pneumonia which is investigated in this study. Intraluminal monofilament model of middle cerebral artery occlusion (MCAO) was constructed in C57BL/6J male mice, and the relative expression of substance P was detected in collected bronchoalveolar lavage fluid (BALF) and lung tissue homogenate at 24 hours, 48 hours, and 72 hours poststroke. On the other hand, different concentrations of aprepitant (0.5, 1, and 2 mg/kg) were atomized and inhaled into MCAO mice. Inflammation cytokines and bacterial load were detected in collected BALF and lung tissue homogenate at 72-hour poststroke, and lung injury was revealed by histological examination. Aprepitant administration decreased total proteins, total cells, neutrophils, and macrophages in BALF. The concentrations of interleukin (IL)-6, IL-1ß, tumor necrosis factor-α, interferon γ, monocyte chemoattractant protein-1, and IL-10 in lung tissue homogenates were also diminished by the administration of aprepitant. In conclusion, aprepitant could attenuate poststroke pneumonia in mice suggesting its potential therapeutic use in the clinic.

Opioid-induced respiratory depression suspected of drug interaction in a prostate cancer patient: a case report.

BACKGROUND: Many of the drugs used for the treatment and alleviation of symptoms in cancer patients are known to inhibit or induce cytochrome P450 (CYP). Therefore, it is important to pay attention to the drug interactions of opioid analgesics that are metabolized by CYPs, because for example when using oxycodone metabolized by CYP3A4, it is possible that the effect will be attenuated or enhanced by the concomitant use of drugs that induce or inhibit CYP3A4. Aprepitant, an antiemetic drug used in many patients receiving anticancer drugs, is known as a moderate competitive inhibitor of CYP3A4. We experienced a case of respiratory depression caused by opioids, which was suspected to be caused by a drug interaction with antiemetics especially aprepitant. CASE DESCRIPTION: The patient was a 72-year-old man. He had been treated with continuous oxycodone infusion for perianal pain associated with the rectal invasion of prostate cancer. No comorbidities other than renal dysfunction were observed. Oxycodone treatment was started at 48 mg/day, and was increased to 108 mg/day, and then the pain decreased. Once the pain was controlled, chemotherapy was planned. Antiemetics (dexamethasone, palonosetron, and aprepitant) were administered before anticancer drug administration. Approximately 3 hours after antiemetics administration and before the administration of the anticancer drugs, a ward nurse noticed that oversedation and respiratory depression had occurred. When the patient was called, he immediately woke up and was able to talk normally, so the anticancer drugs were administered as scheduled. About 2 hours after the nurse noticed oversedation, the attending physician reduced the dose of oxycodone infusion to 48 mg/day. After that, his drowsiness persisted, but his respiratory condition improved. Despite reducing the dose of oxycodone to less than half, the pain remained stable at numeric rating scale (NRS) 0-1, without the use of a rescue dose. The patient was discharged from the hospital 36 days after the administration of anticancer drugs, without any problems. CONCLUSIONS: The cause of respiratory depression in this case was thought to be a combination of factors, including drug interactions between oxycodone and antiemetics, and oxycodone accumulation due to renal dysfunction.

Neurokinin-1 receptor antagonist aprepitant regulates autophagy and apoptosis via ROS/JNK in intrahepatic cholangiocarcinoma.

BACKGROUND: Intrahepatic cholangiocarcinoma (iCCA) has a poor prognosis and limited treatment options. Aprepitant, a selective NK-1R antagonist, can inhibit the growth of various tumours in vitro and in vivo. However, it remains unclear whether aprepitant has cytotoxic effects on iCCA. METHODS: We measured the expression of SP/NK-1R in clinical samples of iCCA by immunohistochemistry. Then, we detected the cytotoxic effects of aprepitant on iCCA cells via MTT, EdU and colony formation assay. We constructed a subcutaneous xenograft model of BALB/c nude mice by using HCCC-9810 and RBE cell lines to explore the effects of aprepitant in vivo. To elucidate the potential mechanisms, we explored the pro-apoptotic effect of aprepitant by flow cytometric, western blotting, ROS detection and JC-1 staining. Furthermore, we detected the autophagic level of HCCC-9810 and RBE by western blotting, mRFP-eGFP-LC3 adenovirus transfection and electron microscope. RESULTS: SP/NK-1R is significantly expressed in iCCA. Aprepitant inhibited human iCCA xenograft growth and dose-dependently decreased the viability of RBE and HCCC-9810 cells. Aprepitant-induced mitochondria-dependent apoptosis through ROS/JNK pathway. Additionally, pretreatment with z-VAD-fmk partly reversed the effect of aprepitant on cell viability, while NAC completely attenuated the cytotoxic effects of aprepitant in vitro. Furthermore, we observed the dynamic changes of autophagosome in RBE and HCCC-9810 cells treated with aprepitant. CONCLUSION: SP/NK-1R signalling is significantly activated in iCCA and promotes the proliferation of iCCA cells. By contrast, aprepitant can induce autophagy and apoptosis in iCCA cells via ROS accumulation and subsequent activation of JNK.

Impact of grinding balls on the size reduction of Aprepitant in wet ball milling procedure.

One of the widely used approaches for improving the dissolution of poorly water-soluble drugs is particle size reduction. Ball milling is a mechanical, top-down technique used to reduce particle size. The effect of ball number, ball size, and milling speed on the properties of milled Aprepitant is evaluated. A full factorial design was employed to investigate the influence of affecting factors on particle size reduction. The initial suspension was made by suspending the drug in distilled water using excipients followed by milling in a planetary ball mill. Ball size, ball number, and milling speed modulated particle size distribution of Aprepitant. Increasing the number of balls from minimum to maximum for each ball size led to approximately a 28% reduction in mean particle size, a 37% decrease in D90%, and a 25% decrease in the ratio of volume mean particle diameter to numeric mean particle diameter. On average, using 10 mm balls instead of 30 mm balls reduced mean particle size by 1.689 µm. As a result, ball size, ball number, and milling speed are three effective factors in the process of ball milling. By increasing the ball number and decreasing the ball size, efficient micronization of drug particles takes place and the particle size is more uniform.