An increasingly competitive pharmaceutical market demands improvement in the efficiency and probability of drug candidate discovery. Usually these new drug candidates are targeted for oral administration, so a detailed understanding of the molecular-level properties that relate to optimal pharmacokinetics is a critical step toward improving the probability of selecting successful clinical candidates. Although the characteristics of druglike molecules have been previously discussed in the literature, the importance of this topic sustains a continued interest for additional perspective and further detailed statistical analyses. In this contribution, we approach the analysis from the perspective of profiling distinguishing features of orally administered drugs. We have compiled both structural and route-administration information for a total of 1729 marketed drugs to provide a solid basis for developing a new perspective on the characteristics of over 1000 orally administered drugs. The molecular properties and most commonly occurring structural elements are statistically analyzed to capture the differences between routes of administration, as well as between marketed drugs and SAR or clinical compounds. We find that, with respect to other routes of administration, oral drugs tend to be lighter and have fewer H-bond donors, acceptors, and rotatable bonds than drugs with other routes of administration. These differences are particularly pronounced when comparing the mean values for oral vs injectable drugs. We also demonstrate that the mean property values for oral drugs do not vary substantially with respect to launch date, suggesting that the range of acceptable oral properties is independent of synthetic complexity or targeted receptor. Finally, we note that, while these properties are descriptive of each class, they are not necessarily predictive of what class any particular drug will reside in, since there is significant overlap in the acceptable ranges found for each drug class.

Our previous studies in human monocytes have demonstrated that interleukin (IL)-10 inhibits lipopolysaccharide (LPS)-stimulated production of inflammatory cytokines, IL-1 beta, IL-6, IL-8, and tumor necrosis factor (TNF)-alpha by blocking gene transcription. Using electrophoretic mobility shift assays (EMSA), we now show that, in monocytes stimulated with LPS or TNF alpha, IL-10 inhibits nuclear stimulation of nuclear factor kappa B (NF kappa B), a transcription factor involved in the expression of inflammatory cytokine genes. Several other transcription factors including NF-IL-6, AP-1, AP-2, GR, CREB, Oct-1, and Sp-1 are not affected by IL-10. This selective inhibition by IL-10 of NF kappa B activation occurs rapidly and in a dose-dependent manner and correlates well with IL-10's cytokine synthesis inhibitory activity in terms of both kinetics and dose responsiveness. Furthermore, compounds such as tosylphenylalanyl chloromethyl ketone and pyrrolidinedithiocarbamate that are known to selectively inhibit NF kappa B activation block cytokine gene transcription in LPS-stimulated monocytes. Taken together, these results suggest that inhibition of NF kappa B activation may be an important mechanism for IL-10 suppression of cytokine gene transcription in human monocytes. IL-4, another cytokine that inhibits cytokine mRNA accumulation in monocytes, shows little inhibitory effect on LPS-induced NF kappa B activation. Further examination reveals that, unlike IL-10, IL-4 enhances mRNA degradation and does not suppress cytokine gene transcription. These data indicate that IL-10 and IL-4 inhibit cytokine production by different mechanisms.

SUMMARYHuman papillomavirus type 16 (HPV16) infection has been linked to the development of cervical and anal dysplasia and cancer. One hallmark of persistent infection is the synthesis of the viral E7 protein in cervical epithelial cells. The expression of E7 in dysplastic and transformed cells and its recognition by the immune system as a foreign antigen make it an ideal target for immunotherapy. Utilizing the E7-expressing murine tumour cell line, TC-1, as a model of cervical carcinoma, an immunotherapy based on the administration of an adjuvant-free fusion protein comprising Mycobacterium bovis BCG heat shock protein (hsp)65 linked to HPV16 E7 (hspE7) has been developed. The data show that prophylactic immunization with hspE7 protects mice against challenge with TC-1 cells and that these tumour-free animals are also protected against re-challenge with TC-1 cells. In addition, therapeutic immunization with hspE7 induces regression of palpable tumours, confers protection against tumour re-challenge and is associated with long-term survival (. 253 days). In vitro analyses indicated that immunization with hspE7 leads to the induction of a Th1-like cell-mediated immune response based on the pattern of secreted cytokines and the presence of cytolytic activity following antigenic recall. In vivo studies using mice with targeted mutations in CD8 or MHC class II or depleted of CD8 or CD4 lymphocyte subsets demonstrate that tumour regression following therapeutic hspE7 immunization is CD8-dependent and CD4-independent. These studies extend previous observations on the induction of cytotoxic T lymphocytes by hsp fusion proteins and are consistent with the clinical application of hspE7 as an immunotherapy for human cervical and anal dysplasia and cancer.

1 GABAB agonists inhibit neuronal processes which are important in the pathogenesis of airway disease, such as bronchospasm. Cough is a prominent symptom of pulmonary disease, but the effects of GABAB agonists on this airway reflex are unknown. Experiments were conducted to determine the antitussive effect of GABAB receptor agonists in comparison to the known antitussive agents, codeine and dextromethorphan. 2 Unanaesthetized guinea-pigs were exposed to aerosols of 0.3 mM capsaicin to elicit coughing, which was detected with a microphone and counted. Cough also was produced in anaesthetized cats by mechanical stimulation of the intrathoracic trachea and was recorded from electromyograms of respiratory muscle activity. 3 In guinea-pigs, the GABAB agonists baclofen and 3-aminopropyl-phosphinic acid (3-APPi) produced dose-dependent inhibition of capsaicin-induced cough when administered by subcutaneous or inhaled routes. The potencies of baclofen and 3-APPi compared favourably with codeine and dextromethorphan.4 The GABAB antagonist, CGP 35348 (0.3-30mg kg-', s.c.) inhibited the antitussive effect of baclofen (3.0mgkg-', s.c.). However, CGP 35348 (10mgkg-', s.c.) had no effect on the antitussive activity of codeine (30mgkg-', s.c.). The antitussive effect of baclofen was not influenced by the GABAA antagonist, bicuculline (3mgkg-', s.c.) or naloxone (0.3mgkg'1, s.c.). 5 In the cat, baclofen (0.3-3.0 mg kg-', i.v.) decreased mechanically-induced cough in a dosedependent manner. In this model, baclofen (ED_0 = 0.63 mg kg-l) was less potent than either codeine or dextromethorphan. The antitussive effect of baclofen in the cat was antagonized by the GABAB antagonists, CGP 35348 (10 mg kg', i.v.) and 3-aminopropylphosphonic acid (3 mg kg', i.v.). 6 We show that baclofen and 3-APPi have antitussive effects in the guinea-pig and cat and these effects are mediated by GABAB receptors.

There is a shift in antimalarial drug discovery from phenotypic screening toward target-based approaches, as more potential drug targets are being validated in Plasmodium species. Given the high attrition rate and high cost of drug discovery, it is important to select the targets most likely to deliver progressible drug candidates. In this paper, we describe the criteria that we consider important for selecting targets for antimalarial drug discovery. We describe the analysis of a number of drug targets in the Malaria Drug Accelerator (MalDA) pipeline, which has allowed us to prioritize targets that are ready to enter the drug discovery process. This selection process has also highlighted where additional data are required to inform target progression or deprioritization of other targets. Finally, we comment on how additional drug targets may be identified.