Basis to Aid Crisis: Favipiravir Oral Solution for Hospital Compounding During COVID-19 Drug Shortage.

The COVID-19 pandemic outbreak has been overwhelming the healthcare system worldwide. A rapidly growing number of younger pediatric patients in Thailand necessitated the formulation of favipiravir, the most locally accessible antiviral agent against COVID-19, into a child-friendly dosage form as a safer alternative to a dispersion of crushed tablets in simple syrup. While striving to quickly develop a liquid formulation that is feasible for any local hospital production units, an oral solution was chosen due to its simplicity. Despite the large dose and poor aqueous solubility of favipiravir, a combination of pH control and use of poloxamer as a solubilizing agent has enabled us to streamline the manufacturing process of a 200 mg/15 mL oral solution for hospital compounding. To ensure its efficacy and safety, a specification for quality control was also established in accordance with the ICH quality guidelines and USP. The finished product stability was subsequently demonstrated under the conditions of 5°C ± 3°C, 25°C ± 2°C/75% RH ± 5% RH, 30°C ± 2°C/75% RH ± 5% RH, and 40°C ± 2°C/75% RH ± 5% RH. The results indicated that our formulation can be stored at 30°C ± 2°C/75% RH for 30 days, which will very well serve the need to allow drug distribution and patient use during the crisis, while the shelf-life can be extended to 60 days when stored at 5°C ± 3°C. Thus, accessibility to an essential medical treatment has been successfully enhanced for pediatric patients in Thailand and neighboring countries during the COVID-19 outbreak.

Double-Filtration Plasmapheresis Plus Low-Dose Anti-thymocyte Globulin and Tacrolimus in Asian Living-Donor Kidney Transplantation With Donor-Specific Anti-HLA Antibody.

BACKGROUND: Pretransplant desensitization protocols, including plasmapheresis, intravenous immunoglobulin, induction antibody therapy, and intensive maintenance immunosuppression, are generally employed in kidney transplant recipients who have positive status for donor-specific anti-HLA antibody (DSA). To avoid serious infectious complications, the authors designed a novel low-dose protocol in Thai patients undergoing DSA+ living-related kidney transplantation (LRKT). METHODS: A retrospective cohort study of the patients who underwent DSA+ LRKT was conducted. The novel protocol consisted of 3 to 5 sessions of pretransplant double-filtration plasmapheresis (DFPP) with or without low-dose intravenous immunoglobulin together with low-dose anti-thymocyte globulin (ATG) induction (1-1.5 mg/kg/d for 3-4 days) and low-dose tacrolimus (Tac) (trough level 5-10 ng/mL), mycophenolate, and prednisolone. RESULTS: The study included 17 patients. The lymphocyte crossmatch via complement-dependent cytotoxicity was negative in 12 patients and positive for B cell immunoglobulin M in 5 patients. The novel desensitization protocol resulted in a decrease of at least 50% of DSA mean fluorescence intensity from baseline (from 4320 ± 549 before DFPP to 1601 ± 350 before transplantation, P < .005) and successful kidney transplantation with good allograft function in all cases. Early DSA rebound was observed in 3 patients after transplantation, and kidney biopsy revealed subclinical antibody-mediated rejection in 1 patient and diffuse C4d staining without cell infiltration in 2 patients. There were good long-term outcomes in patient and graft survival (100% and 94.1%, respectively). Only 1 allograft loss occurred because of nonadherence. The majority of patients have stable allograft function with serum creatinine less than 1.5 mg/dL. However, infections, including CMV and other organisms, were commonly observed. CONCLUSIONS: Desensitization protocol with DFPP, low-dose ATG, and Tac provides excellent outcomes in living donor kidney transplantation in highly sensitized Asian populations.

Impact of POR and CYP3A5 Polymorphisms on Trough Concentration to Dose Ratio of Tacrolimus in the Early Post-operative Period Following Kidney Transplantation.

BACKGROUND: Tacrolimus, a critical dose drug, is widely used in transplantation. Knowing the contribution of genetic factors, which significantly influence tacrolimus variability, is beneficial in the personalization of its starting dose. The significant impact of CYP3A5*3 polymorphisms on tacrolimus exposure has been reported. Conflicting results of the additional influence of POR*28 polymorphisms on tacrolimus pharmacokinetic interindividual variability have been observed among different populations. The objective of this study was to explore the interaction between POR*28 and CYP3A5*3 polymorphisms and their main effects on tacrolimus trough concentration to dose ratios on day 7 after kidney transplantation. METHODS: Two hundred sixteen adult kidney transplant recipients participated in this retrospective study. All participants received a twice daily tacrolimus regimen. Blood samples and data were collected on day 7 after transplantation. A 2-way analysis of covariance was performed. Tested covariates were age, hemoglobin, serum albumin, and prednisolone dose. RESULTS: A 2 × 2 analysis of covariance revealed that the interaction between CYP3A5 polymorphisms (CYP3A5 expresser and CYP3A5 nonexpresser) and POR polymorphisms (POR*28 carrier and POR*28 noncarrier) was not significant (F(1, 209) = 2.473, P = 0.117, (Equation is included in full-text article.)= 0.012). The predicted main effect of CYP3A5 and POR polymorphisms was significant (F(1, 209) = 105.565, P < 0.001, (Equation is included in full-text article.)= 0.336 and F(1, 209) = 4.007, P = 0.047, (Equation is included in full-text article.)= 0.019, respectively). Hemoglobin, age, and steroid dose influenced log C0/dose of tacrolimus (F(1, 209) = 20.612, P < 0.001, (Equation is included in full-text article.)= 0.090; F(1, 209) = 14.360, P < 0.001, (Equation is included in full-text article.)= 0.064; and F(1, 209) = 5.512, P = 0.020, (Equation is included in full-text article.)= 0.026, respectively). CONCLUSIONS: After adjusting for the influences of hemoglobin, age, and prednisolone dose, significant impacts of the CYP3A5 and POR polymorphisms on tacrolimus exposure were found. The effect of POR*28 and CYP3A5*3 polymorphisms during the very early period after kidney transplantation is independent of each other.

Impact of CYP3A5 polymorphism on trough concentrations and outcomes of tacrolimus minimization during the early period after kidney transplantation.

PURPOSE: The purpose of this study is to determine the impacts of CYP3A5 polymorphism on tacrolimus concentration and the proportion of patients within a target therapeutic range during the first week after transplantation together with the 3-month acute rejection rate in kidney transplant patients receiving a minimized tacrolimus regimen. METHODS: A total of 164 patients participated in the study. All received oral tacrolimus twice daily starting on the day of surgery with the target pre-dose (trough) concentration of 4-8 ng/ml for prevention of allograft rejection. Cytochrome P450 (CYP) 3A5 genotypes were determined. The patients were divided into CYP3A5 expressers (CYP3A5*1 allele carriers) and CYP3A5 nonexpressers (homozygous CYP3A5*3). Whole blood tacrolimus concentrations on days 3 and 7 posttransplantation and the incidence of biopsy-proven acute rejection (BPAR) at 3-month posttransplantation were compared between groups. RESULTS: On day 3, the median (IQR) dose-and-weight-normalized trough concentration in expressers and nonexpressers were 54.61 (31.98, 78.87) and 91.80 (57.60, 130.20) ng/ml per mg/kg/day, respectively (p < 0.001). Although only 47 and 42% of expressers and nonexpressers were within the target range on day 3, approximately 60% of both groups were within the target range on day 7. Proportions of BPAR among expressers and nonexpressers were 6.0 and 7.4 %, respectively (p = 0.723). The median (IQR) times to the first rejection in CYP3A5 expressers and nonexpressers were 32 (12, 68) and 15 (12, 37) days, respectively (p = 0.410). CONCLUSIONS: Although CYP3A5 polymorphism significantly influenced the tacrolimus dose required to achieve the target concentration, the impact of CYP3A5 polymorphism on BPAR was not observed in this study.

Steady-state serum phenytoin concentrations after nasogastric tube administration of immediate-release phenytoin tablets and extended-release phenytoin capsules: an open-label, crossover, clinical trial.

BACKGROUND: When phenytoin is prescribed for administration via nasogastric tube, immediate-release OR) phenytoin tablets are crushed before use and extended-release (ER) phenytoin capsules are opened and only the granules are used. However, it is unknown whether the same dose of these 2 different formulations will result in the same steady-state serum phenytoin concentration. OBJECTIVE: The aim of this study was to determine whether ER phenytoin capsules can be used interchangeably with IR phenytoin tablets for prophylaxis of posttraumatic seizures. METHODS: Inpatients at the neurosurgical ward at Prasat Neurological Institute, Bangkok, Thailand, between October 2004 and October 2005 were enrolled in the study. All patients were initially prescribed IR phenytoin tablets 300 mg/d as a maintenance dose for prophylaxis of posttraumatic seizures. The serum phenytoin concentration was measured after ≥5 days of treatment with IR phenytoin tablets 300 mg/d (two 50-mg tablets every 8 hours) that had been crushed before being administered concomitantly with a blenderized diet through the nasogastric tube. Without a washout period, the dosage form was changed to ER phenytoin capsules (three 100-mg capsules QD). The capsules were opened and the contents were administered concomitantly with the blenderized diet through the nasogastric tube for ≥5 days. The serum phenytoin concentration was again determined. The patients were closely monitored for seizures and adverse events (AEs). RESULTS: Thirty-three patients enrolled in the study and 17 (10 women, 7 men; mean [SD] age, 62.94 [15.94] years [range, 18-89 years]) completed the study. The mean (SD) serum phenytoin concentrations after administration of phenytoin tablets and capsules were 6.03 (5.92) µg/mL and 3.80 (2.71) µg/mL, respectively (P = 0.019). The mean serum phenytoin concentrations, adjusted for low serum albumin concentrations after administration of tablets and capsules, were calculated and reported to be 10.33 (11.60) µg/mL and 6.28 (4.76) µg/mL, respectively (P = 0.035). The maximum phenytoin metabolic rate (Vmax) (assuming the substrate concentration at which the rate of metabolism is one half Vmax = 4 mg/L) after the administration of phenytoin tablets and capsules was 8.37 (2.42) mg/kg · d(-1) and 10.38 (6.48) mg/kg · d(-1), respectively. These values were not significantly different. All patients were seizure-free and no AEs were observed. CONCLUSION: The steady-state serum phenytoin concentration was significantly lower with ER phenytoin capsules 300 mg/d than IR phenytoin tablets 300 mg/d administered via nasogastric feeding tube concomitantly administered with a blenderized diet in these neurosurgical patients. Key words: phenytoin nasogastric tube feeding extended-release capsule immediate-release tablet.