The effect of food and liquid pH on the integrity of enteric-coated beads from cysteamine bitartrate delayed-release capsules.

BACKGROUND: Cysteamine bitartrate delayed-release (DR) capsule (Procysbi®) is approved for treatment of nephropathic cystinosis in the USA, Canada, and the EU. The capsules contain cysteamine bitartrate beads that are enteric coated with acid-resistant Eudragit L 30 D-55, preventing drug release in the acidic stomach environment while allowing dissolution of the beads in the more alkaline environment of the small intestine. Patients who have difficulty swallowing capsules can open capsules, sprinkle beads onto 4 ounces of a suitable food or liquid, gently mix, and consume the entire content within 30 minutes. Foods found to be suitable for administration, and described in the Procysbi US labeling, include fruit juices (except grapefruit juice), applesauce, and berry jelly; there are minor variations in the foods and liquids recommended by regulatory authorities in other countries. This study aimed to assess the stability of enteric-coated beads exposed to additional foods at different conditions to expand the list of suitable foods for drug administration. METHODS: For each test condition, beads from eight opened 75 mg cysteamine bitartrate DR capsules were gently mixed with test food and maintained at a prespecified temperature and duration; remaining undissolved beads were then recovered from the food. The recovered beads were split into two portions: one assayed for remaining drug content and the other subjected to dissolution testing to assess the effect on the drug-release profile. RESULTS: The results show that bead integrity was maintained when mixed with foods at pH values <5.5 at all time points when refrigerated (2°C-8°C) and at room (20°C-22°C) and lukewarm (37°C-41°C) temperatures. Bead integrity was not maintained when mixed with foods at pH values of ≥5.5 at room temperature. CONCLUSION: The results from this in vitro dissolution study help in identifying additional foods that may be used for the administration of cysteamine bitartrate DR beads from opened capsules using the sprinkle method.

Functional mimicry of the LDL receptor-associated protein through multimerization of a minimized third domain.

The LDL receptor-associated protein (RAP) is a ligand for the LDL receptor-related protein (LRP1). The first and third domains of RAP can each bind to one of many sequence-related pairs of complement-type repeats (CR) found within the LRP1 ectodomain. Multiple sites of interaction between the multivalent RAP ligand and the multivalent LRP1 receptor yield strong binding avidity for the complex. The third domain of RAP can be significantly truncated, with material retention of monovalent CR pair-binding affinity, provided that the minimized sequence is stabilized with an intramolecular disulfide bond. We demonstrate that the avidity of full-length RAP for LRP1 in vitro can be partially reconstituted by assembly of truncated, disulfide-linked RAP peptides on tetravalent streptavidin or bivalent immunoglobulin scaffolds. The peptide complex with streptavidin shows pronounced hepatotropism in vivo, replicating the biodistribution of full-length RAP.

HIV-Related Cognitive Impairment of Orphans in Myanmar With Vertically Transmitted HIV Taking Antiretroviral Therapy.

OBJECTIVE: We determined the effect of perinatally acquired HIV on neurocognition in Myanmar children treated with antiretroviral therapy by comparison to demographically matched seronegative children. BACKGROUND: Myanmar has one of the highest HIV-1 prevalence rates in Southeast Asia. Studies from other resource-poor countries have shown that HIV-infected children differ in socioeconomic, nutritional and caregiver status compared to normal controls. Some vertically infected orphans in Myanmar reside separately from HIV-uninfected children in separate orphanages, thus the demographic variables of interest are naturally controlled. This study provides a unique evaluation of the neurocognitive effects of HIV in children, with control over key demographic variables. We hypothesized that HIV-infected orphans would perform significantly worse on cognitive indices compared with HIV-negative orphans. DESIGN/METHODS: A battery of cognitive tests sensitive to HIV-associated impairments in children was administered to 28 perinatally acquired HIV-positive children and 31 HIV-negative children from two orphanages in Myanmar; 21 children from each cohort underwent testing at baseline and again after 12 months. RESULTS: Baseline comparison of the two groups indicated that the HIV-infected children performed poorly across all tests, with significant group differences in executive function, visuospatial reasoning, fine motor dexterity, and visual motor integration. On subsequent testing, both cohorts of children showed improvements across multiple domains, with no significant effect of age at treatment initiation. CONCLUSIONS: Our results demonstrate a strong effect of HIV infection on specific neurocognitive deficits in vertically infected children. Understanding viral and host determinants and timing and choice of antiretroviral therapy on cognition will be critical to preventing cognitive impairment of children with HIV.

Prevalence of white matter lesions and stroke in children with migraine.

OBJECTIVES: To determine the prevalence of white matter lesions (WMLs) and infarcts in children with migraine and whether pediatric migraine could be a risk factor for silent ischemic lesions or stroke. METHODS: Prospectively collected data from 1,008 pediatric patients with headache were reviewed. The MRI data were collected and retrospectively reviewed. RESULTS: Of the 926 patients diagnosed with migraine, 375 patients had MRIs and 115 had abnormalities, of which 39 had WMLs. Among them, 24 (6% of migraine) patients had incidental white matter findings without known neurovascular disease, risk factors, or etiologies for WMLs. The prevalence of WMLs is more common in migraine with aura (10%) than without aura (4%) (p = 0.038), but it is not statistically significant compared with controls (4%) (p = 0.119). Deep WMLs are more prevalent than periventricular lesions; these are detected mainly in the frontal and parietal lobes. No lesions appeared to be infarct-like lesions. There was no association between the total lesion load and chronicity or the frequency of migraine. WMLs are nonprogressive. Pediatric migraineurs with aura do not develop stroke, based on the available follow-up data. CONCLUSION: WMLs in pediatric patients with migraine and aura are no more prevalent than in controls. They appear to be benign and are not associated with stroke.

Minimization of the third domain of the LDL receptor-associated protein (RAP).

The third domain of the low-density lipoprotein receptor-associated protein (RAP d3) binds with high-affinity to pairs of complement-type repeats (CR) within the LDLR family of receptors. Structural analyses have defined the contact surface between RAP d3 and a CR pair from the low-density lipoprotein receptor (LDLR). Much of the sequence of RAP d3 has been proposed to stabilize the receptor-binding region without participating directly in formation of the contact surface. We have developed a truncated version of RAP d3 in which these scaffolding regions are excised and replaced with a single, intramolecular disulfide bond. This substitution allows for deletion of as much as a third of the RAP d3 sequence with substantial retention of receptor-binding ability.